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USER`S MANUAL

1. Using Internal Excitation a RI TB1 Connections Using External Excitation IPS lead Rlead diber gt 0 SEN SEN ME IN f IN IN 3 IN sEN Q SEN i EXC EXC NOTE You Must Jumper NO EXC Terminals To SEN Terminals As Shown CAUTION The Internal Excitation Supply Must Be Turned OFF Prior To Connecting To An External Excitation Supply 30 4501 887A IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input TRIG input is optically isolated and ANALOG OUTPUT SHIELDED CABLE DIGITAL INPUT includes a 6 65K series connected D resistor TRIG is asserted for TRIG VOLTAGE voltages from 15 30V OUT LOAD DC ee dedo ES die 2 OUTPUT OR L 5 POWER S rnc TRIG CUR
2. ANALOG OUTPUT SPECIFICATIONS RELAY OUTPUT SPECIFICATIONS ENCLOSURE PHYSICAL SPECIFICATIONS APPROVALS ENVIRONMENTAL SPECIFICATIONS FIELD CONFIGURATION AND CONTROLS HOST COMPUTER COMMUNICATION INO NO INO ND ID ND 2A A A CA CA DA DA LA DA DA Di LA A 5 5 5 gt gt gt gt SOFTWARE 24 List of Drawings Page Simplified Schematic 4501 884 29 Functional Block Diagram 4501 885 29 Computer to IntelliPack Connections 4501 643 30 Bridge Completion Connections 4501 887 30 Electrical Connections Pg 1 of 2 4501 886 31 Electrical Connections Pg 2 of 2 4501 886 31 Interposing Relay Conn amp Contact Pro 4501 646 32 Enclosure Dimensions 4501 888 32 Windows 95 98 2000 NT are registered trademarks of Microsoft Corporation IMPORTANT SAFETY CONSIDERATIONS It is very important for the user to consider the possible adverse effects of power wiring component sensor or software failures in designing any type
3. 1 Power Refer to Electrical Connections Drawing 4501 886 Variations in power supply voltage within rated limits has negligible effect on module accuracy For supply connections use No 14 AWG wires rated for at least 75 C The power terminal is series diode coupled for reverse polarity protection 2 Input Connect input per Electrical Connections Drawing 4501 886 Observe proper polarity when making connections see label for input type IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input IMPORTANT If the module is powered up prior to completing the input connections the self calibration routine will cause an offset error to be present once the input connections are completed You may correct this error by resetting the module or cycling power after completing the input connections It is recommended that you always complete the input connections prior to applying power External Excitation If you wish to use your own power supply to excite the bridge you must first turn the internal excitation supply OFF This module uses a method of ratiometric conversion in which the A D reference is derived from the excitation supply voltage As such you must also complete the remote sense circuit by connecting your excitation supply to the input sense leads SEN and SEN Refer to Drawing 4501 887 for more information Bridge Completion If your load cell requires half or quarter bridge completion and you
4. Before attempting field calibration consider that in the field the use of an application s actual sensor load cell or bridge arrangement can make field calibration impractical in some cases as it would require that precise calibration loads or stresses be applied including load equivalents for alarm levels as well as zero and full scale Further the accurate simulation of strain gauge bridges is often impractical due to wide variances in their application and offsets Complete calibration is most easily accomplished via the IntelliPack Configuration Software Transmitter Alarm General Field Programming Procedure Field configuration of zero and full scale via the front panel push buttons is essentially equivalent to the scaling operation performed via the Transmitter Configuration page of the IntelliPack software That is you define the input for 0 output and the input for 100 output However in field calibration you may map a minimum input signal to an output signal up to 2096 of nominal full scale and a maximum input signal to an output signal from 60 to 110 of nominal full scale In other words your zero calibration may include offset up to 2096 and you do not have to use an equivalent full scale load to accurately calibrate your output response you can use 60 110 of full scale You may choose to include tare in your field zero calibration but are limited to 2096 of full scale For greater tare weights you can always t
5. it also accounts for the effect of the transverse strain and Poisson s Ratio is included This configuration is primarily used for uniaxial induced strain at higher levels of stress That is with higher stress levels come higher transverse strains Thus a second active gauge is mounted in the transverse direction to measure the increased level of Poisson s Strain that occurs as a result of the strain induced in the primary axial direction the other active gauge measures the primary strain The presence of the second gauge also corrects for the change in gauge resistance due to temperature just as for the Quarter Bridge Type II circuit RI E r e O O E Fs RI Half Bridge Type II Bending Strain Solving for the resultant strain of the Half bridge Type II configuration yields note the absence of Poisson s Ratio E 2Vr 1 RI Rg GF IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input The Half Bridge Type 1 configuration uses two active gauges with equal and opposite strains typical of a bending beam application In these applications a second active strain gauge is mounted in a position that causes it to compress while the other strain gauge undergoes tension review the balanced beam example presented earlier Unlike the compressive transverse strain of the Half Bridge Type configuration the second gauge of the Type II configuration does not measure transverse strain However
6. Applicable IEC Safety Standards may require that this device be mounted within an approved metal enclosure or sub system particularly for applications with voltages greater than or equal to 75VDC or 50VAC Refer to Table 2 Your application may differ from the default configuration shown and will require that the transmitter be reconfigured to suit your needs This is accomplished with Acromag s user friendly Windows 95 98 2000 or NT Configuration Program and Serial Port Adapter Configuration is normally done prior to field installation since field configurability via the module s push buttons is generally limited to zero full scale setpoint and dropout adjustments Note that Tare offset generation can also be triggered remotely in the field via a wired digital input signal at the TRIG amp COM inputs asserted high 11 Table 2 851T Default Factory Configuration Transmitter Scaling Input for 0 Output OmV MEE M Input for 100 Output 30mV Jumper Installation For Voltage Output Only For voltage output a short jumper must be installed between the output I and JMP terminals A jumper wire has been included with the unit and is already installed between the JMP and 1 terminals Verify jumper installation if your application requires output voltage Remove this jumper for current output applications Refer to the Electrical Connections Drawing 4501 886 Bridge Completion Jumper Installation Ref
7. IMPORTANT Noise and or jitter on the input signal has the effect of reducing narrowing the instrument s deadband and may produce contact chatter The long term effect of this will reduce the life of mechanical relays To reduce this undesired effect you should increase the effective deadband Note that the input averaging function of this transmitter may also be used to reduce contact chatter but at the expense of increasing the effective response time 5 Grounding See Electrical Connections Drawing 4501 886 The module housing is plastic and does not require an earth ground connection Input EXC may be earth grounded WARNING For compliance to applicable safety and performance standards the use of shielded cable is recommended as shown in Drawing 4501 886 Further the application of earth ground must be in place as shown in Drawing 4501 886 Failure to adhere to sound wiring and grounding practices may compromise safety amp performance 3 0 CALIBRATION AND ADJUSTMENT This transmitter alarm module needs to be configured for your application Complete configuration is normally accomplished using Acromag s Windows 95 98 2000 or NT IntelliPack Configuration Program and Serial Port Adapter This software provides controls for calibrating various aspects of the input module and the strain gauge sensor Additionally field controls for adjustment of transmitter zero full scale span alarm setpoint amp alarm dropout deadba
8. Input Reference Test Conditions 1200 Bridge 10V Excitation 2mV V Rated Output 20mV 410096 input range 25 C ambient 24VDC Power 200ms Alarm Delay Input Span Range All input ranges are bipolar and determined from the product of the gauge s rated output and the excitation voltage selection Input Over Range The actual internal input range is 150 typical of the range obtained via the product of the gauge s rated output and the excitation selected Input Accuracy Better than 0 1 of span typical for bipolar ranges larger than or equal to 10mV This includes the effects of repeatability and terminal point conformity but does not include sensor error Accuracy noted refers to input measurement amp alarm but does not include output accuracy Input Sensitivity Accepts gauge rated outputs from 1mV V to 10mV V The input signal range is the bipolar product of your excitation voltage and your gauge s rated output Input Impedance Minimum IN at 1MO SEN at 29KQ Input Bias Current 1nA typical at IN Input Lead Resistance Module has sufficient overdrive to guaranty 10V of bridge excitation with 5Q lead and 100mA of excitation current Larger lead resistances or higher currents will limit the maximum bridge excitation that can be achieved Input Lead Break Detection Output will be driven upscale within 1 55 for wire harness failure all 6 or 4 leads open Output moves upscale for a single IN lead break and downscale
9. an opto coupler Be sure to limit power dissipation in this resistor to 0 125W less Note if TRIG is held high the tare function will be repeated continuously COM Common for TRIG digital input signal LED Indicators Operating Mode Run Green Constant ON indicates normal operation and power is applied Flashing ON OFF indicates unit is IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input performing diagnostics first second following power up or has failed diagnostics after a few seconds Status Yellow Flashing ON OFF indicates an open sensor or that the input is outside of the selected input range A constant ON indicates the input is outside of the transmitter s calibrated input range Zero Full Scale Yellow OFF in Run mode Relay Yellow Constant ON indicates alarm condition for relay During field configuration this LED has a different function see below LED Indicators Field Configuration Mode Run Green Turned OFF in this mode Status Yellow Flashes each time the SET push button is pressed to capture I O signal in this mode Zero Full Scale Yellow ON or FLASHING in this mode if zero or full scale is being adjusted See Table 4 Relay Yellow ON or FLASHING if alarm setpoint or dropout is being adjusted See Table 3 in this mode HOST COMPUTER COMMUNICATION Host Communication Port SPI IntelliPack SPI port standard RJ11 6 wire ph
10. our active gauge and Rg for R3 our dummy gauge and by mounting the dummy gauge in the transverse direction with respect to the active gauge perpendicular to the applied strain the applied strain has little effect on the dummy gauge but the ambient temperature will affect both gauges in the same way That is because their temperature effects are equal the ratio of their resistance does not change and the corresponding output voltage Vo does not change effect of temperature is minimized If you choose to make the second gauge active but in a different direction e g one active gauge in tension one active gauge in compression you form a half bridge configuration that effectively doubles the sensitivity of the bridge to strain That is the resultant output voltage is linear and approximately double the output of the quarter bridge circuit for the same excitation Consider the balance beam application shown below Solving for the sensitivity in this half bridge application yields VolVex GF 2 In the figure note that the direction of the arrows opposing depicts that the two active gauges are mounted such that one is in compression and the other in tension for the same applied strain Tension gauge in tension Rgt AR Rg AR V Rg AR Rg AR Compression gauge in compression You can further increase the sensitivity of this bridge circuit by making all four arms of the bridge active str
11. 563 Transmitter Configuration Manual 8500 570 Serial Port Adapter 5030 913 and Cable 5030 902 into a complete kit for interfacing with IntelliPack Alarms and Transmitters INTRODUCTION TO STRAIN Because the concept of strain and its measurement amp application are complex subjects the following information has been included to help you gain a better understanding of this module and its operation If you are already familiar with strain concepts and their application then you may skip this section and proceed to Section 2 0 PREPARATION FOR USE Strain sensors are used to measure stress forces that result from loading torque pressure acceleration and vibration These devices are commonly arranged in Wheatstone bridge fashion The output voltage of the strain gauge bridge is directly proportional to the applied excitation and any resistance imbalance in the arms of the bridge The output of the bridge is normally specified in terms of millivolts of output voltage per volt of applied excitation mV V and this is usually referred to as its rated output or sensitivity The actual maximum or full scale output of a strain gauge bridge at its full rated load is the product of a bridge s sensitivity mV V and the applied excitation voltage This is referred to as the output span under full rated load IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Strain is a measure of the deformation of a bod
12. 851T 1500 units include an alarm relay that may be configured as a limit alarm with deadband applied and with latching or non latching contacts in failsafe or non failsafe modes A programmed relay time delay may be implemented to help filter transients and minimize nuisance alarms Units are DIN rail mounted and removable terminal blocks facilitate ease of installation and replacement without having to remove wiring Transmitter power output and relay wiring are inserted at one side of the unit while input wiring is inserted at the other side Plug in connectors are an industry standard screw clamp type that accept a wide range of wire sizes All IntelliPack modules are designed to withstand harsh industrial environments They feature RFI EMI ESD EFT and surge protection plus low temperature drift wide ambient temperature operation and isolation between input power output and relay contacts They also have low radiated emissions per CE requirements As a wide range DC powered device the unit may be powered from DC power networks incorporating battery backup Since the input power is diode coupled this offers reverse polarity protection and permits the unit to be connected to redundant power supplies It also allows several units to safely share a single DC supply Flexible transmitter functionality convenient reconfiguration plus an optional alarm all combine in a single package to make this instrument extremely powerful
13. CONVERSION ee i FILTER amp C aW LAMPS SEN 12K INT FLASH 3 5V to 11 4V F NU POWER ISOLATED UP Dr A Y PM ALARM FLYBACK TOABV OE STATUS LED _ C reer OUTPUT PWR 15V FLTR INSTALL JUMPER FOR VOLTAGE OUT N RELAY r Q NO1 R BRIDGE RJ11 lv ISOL Y E COMPLETION L cm y CONFIG PORT 2 a FRONT PANEL MODE SET PUSH BUTTONS UP DOWN j RELAY ISOLATION S ISOLATEDINPUT 5V TRIGGER iik GE MODEL 851T 1500 x acc STRAIN GUAGE TRANSMITTER ALARM serine MO D ELS 85 1 T 0500 85 1 T 1 500 Setpoints and Deadbands Configuration Variables Full Sensor Input Range TRAN S M ITT E R ALARM Configuration Software or ROS DEW Alarm Push Buttons elay Alarm Delay FUNCTIONAL BLOCK DIAGRAM E Automate Rese ar Latching Failsafe Non Failsafe Digital Process Variable PV Reading on PC Monitor RELAY CONTACTS Microstrain lt PV SPDT Form C Millivolts percent Relay 851T 1500 SPDT SP amp DB ALARM OUTPUT Bridge Type BLOCK BLOCK Gauge Resistance 2 Lead Resistance Wide Range Configuration Gauge Factor o Zero Full Scale Input for Zero Full Scale Output Poisson s Ratio 8 Configuration Software Sensitivity E Module Push Buttons Analog
14. Note that problems may also arise if you elect to make your own Intellipack cable and exceed about 6 feet in length Acromag s Application Engineers can provide further technical assistance if required When needed complete repair services are available from Acromag 6 0 SPECIFICATIONS General The IntelliPack Model 851T 0500 is a DC powered transmitter which conditions either a single strain gauge transducer or Wheatstone bridge input and provides an isolated voltage or current output Isolation is supplied between the inputs the output and power Model 8511 1500 units also include a SPDT Form C electromechanical relay which provides a local limit alarm function with isolated relay contacts This transmitter alarm is DIN rail mounted 20 The unit is configured and calibrated with our user friendly Window 95 98 2000 or NT IntelliPack Configuration Program Push buttons on the module allow adjustment to the zero and full scale points for the transmitter plus setpoint and deadband and may act as a latched alarm reset for modules with the alarm option An isolated digital input is included to remotely trigger tare conversions or to reset a latched alarm relay Non volatile reprogrammable memory in the module stores calibration and configuration information MODEL NUMBER DEFINITION Transmitters are color coded with a white label The prefix 8 denotes the IntelliPack Series 800 while the T suffix specifies that
15. Requires Half Bridge Completion Resistors Full Bridge N 4 Vr GF 4Vr N GF Bending Beam Strain or Shafts Under Torsion with Gauge Pairs Measuring Equal and Opposite Strains One Opposite Leg Pair Measures Compression While Other Opposite Leg Pair Measures Full Bridge Type II N 2 1 y 2Vr GF y 1 4Vr N GF Uniaxial Column Strain with One Gauge Pair Measuring the Principal Tensile and Compressive Strains and the Opposite Gauge Pair Measuring the Corresponding Transverse Poisson s Strains One Half of Bridge Measures the Principal Tensile and Compressive Strain Other Half Measures the Coincident Compressive and Tensile Poisson s Strains Full Bridge Type 1 N 2 1 2Vr GF Y 1 Vr Y 1 Uniaxial Column Strain with One Gauge Pair Measuring the Principal Tensile Strain and the Opposite Gauge Pair Measuring the Compressive Transverse Poisson s Strain 10 One Opposite Gauge Pair Diagonal Measures Principal Tensile Strain and Other Opposite Gauge Pair Measures the Compressive Transverse Poisson s Strain IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input 2 0 PREPARATION FOR USE UNPACKING AND INSPECTION Upon receipt of this product inspect the shipping carton for evidence of mishandling during transit If the shipping carton is badly damaged or water stained request that the carrier s agent be present
16. SEN Remote sensing will allow the module to boost the output level so that the programmed excitation level is maintained at the remote bridge effectively correcting for any lead resistance drop These lines also drive the divider used to generate the reference to the A D A fixed reference voltage input to a second channel of the A D the actual A D reference varies with excitation level allows the excitation level to be read back in closed loop fashion This permits the unit to make adjustments to the excitation level in order to compensate for load lead wire and temperature effects You simply enter the excitation level you desire and the unit adjusts to that level The excitation supply also has sufficient overdrive capability to allow up to 1V of total EXC lead resistance drop Note that in some cases resolution limitations will only allow the module to approximate your nominal excitation level typically to within 93mV Higher than expected lead wire resistance may also limit the excitation level obtained at the bridge In any case the software displays the actual excitation level obtained at the bridge via the remote sense leads and this may differ from your desired excitation IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input If you wish to drive your bridge via your own excitation Source the IntelliPack Configuration Software allows you to turn OFF the internal excitation supply In this mode you m
17. active gauge impedance and temperature performance making pre selection impractical Remote Tare Adjustment Auto tare is built into this module and allows the cancellation or taring of non zero dead weight or other sensor offsets For example it is commonly used to remove the weight of a container from a load cell measurement It may also be used to correct for imbalances in the input bridge or load cell circuitry This model provides separate controls for zero balance and tare adjustment Tare adjustment is accomplished two ways via the Tare push button of the Configuration Software Test Page or via an asserted digital input signal at the isolated input The Tare trigger is asserted high with a voltage from 15 30V with respect to COM at the TRIG terminal If your application requires frequent tare adjustment in the field then you will have to make provisions for wiring to the TRIG and COM terminals as part of your installation Separately you may also have to use the IntelliPack Software to configure this digital input for tare as it can alternately be used to reset a latched alarm relay it is set to trigger tare by default Note that a tare offset will take effect immediately but is only stored to non volatile EEPROM memory after 10 seconds of TRIG inactivity If power is lost during this interim period your tare offset will be lost also This may seem inconvenient but is done to help preserve the life of the EEPROM while
18. best results However if Shielded 3 TTT TTI sensors are inherently connected to ground use caution and avoid making additional Aid inpe rrai ac duster i See Bridge Completion and Shunt ground connections which could generate ground loops and measurement error BRIDGE COMPLETION Input Connections Below Calibration Connections at left NOTE 2 Be sure to complete input connections prior to bridge completion or if using a millivolt signal source i H INTERNAL EXC applying power or resetting the module Tu HALE GRICE NUS iat ses tcl 4 ote that quarter bridge WARNING S emwetwrewetas ELECTRICAL CONNECTIONS For compliance to applicable safety and performance standards the use of 2K dummy gauge be located shielded cable is recommended as shown Additionally the application of JUMPER LS HALF pe the active Gale rok MODELS 851T 0500 AND 851T 1500 earth ground must be in place as shown in this drawing Failure to adhere to S
19. for a single IN lead break The output will move upscale for all other individual and combination wire failures except for SEN alone and SEN with IN Note Lead Break Detection w External Excitation If you are using an external excitation supply you must jumper the module s EXC excitation terminals to their adjacent SEN sense terminals to properly detect sense lead breakage Note that the sense lead wiring is still required with external excitation as the A D reference for this model is derived from the excitation supply voltage delivered via the SEN leads Input Bridge Excitation Internal Adjustable from 4V to 11V 100 points up to 120mA For maximum rated ambient temperature the bridge resistance should be greater than or equal to 3500 For bridge resistance from 3500 down to 1200 limit maximum ambient to 60 C For applications with an effective bridge resistance between 87 50 four parallel 3500 bridges 1200 the maximum ambient temperature should be limited to 50 C Lower bridge resistances may cause the internal excitation to thermal limit Use of optional external bridge excitation does not limit the maximum ambient below 70 C Internal excitation must be turned OFF for external excitation supply connections The internal excitation voltage will be automatically boosted if it drops by approximately 60mV 21 Input Bridge Excitation External 4V to 11V Internal excitation must be turned OFF prior to conne
20. fuse rated for a maximum current of 1A or less for example see Bel Fuse MJS1 Power Supply Effect DC Volts Less than 0 00196 of output span change per volt DC for rated power supply variations 60 120 Hz Ripple Less than 0 0196 of output span per volt peak to peak of power supply ripple 23 Isolation Input output and power circuits are isolated from each other for common mode voltages up to 250VAC or 354V DC off DC power ground on a continuous basis will withstand 1500VAC dielectric strength test for one minute without breakdown Optional relay outputs are isolated from other circuits up to 150VAC or 150VDC This complies with test requirements of ANSI ISA 82 01 1988 for the voltage rating specified Installation Category Designed to operate in an Installation Category for use in a Pollution Degree 2 environment Overvoltage Category Il rating Radiated Field Immunity RFI Complies with IEC1000 4 3 Level 3 10V M 80 to 1000MHz AM amp 900MHz keyed and European Norm EN50082 1 Electromagnetic Interference Immunity EMI No relay trips will occur beyond 0 25 of input span from setpoint and no output shifts will occur beyond 0 25 of span under the influence of EMI from switching solenoids commutator motors and drill motors Electrical Fast Transient Immunity EFT Complies with IEC1000 4 4 Level 2KV power 1KV signal lines and European Norm EN50082 1 Electrostatic Discharge ESD Immunity Complie
21. how many active load cells are present An active cell is mounted such that it will measure strain in the same direction as an applied force either tensile or compressive One active load cell will form a Quarter Bridge two active load cells will form a Half Bridge and four active load cells will form a Full Bridge If your bridge has one active gauge and no additional dummy gauges or resistive elements present then you select a Quarter Bridge Type formulation However If your sensor has one active gauge plus a second passive or dummy gauge mounted transverse to the applied stress to provide temperature compensation then you select Quarter Bridge Type Il In any case the same formula for calculating strain applies to both Quarter Bridge types and the type distinction simply serves to specify whether the gauge is temperature compensated or not and the steps that are necessary to complete the wiring for the full bridge input of the 851T module For example both types will require half bridge completion resistors either external or internal and Type will require that a third resistor be connected in an adjacent arm to the active gauge and selected to match the resistance of the active gauge If your bridge has two active gauges with the second active gauge mounted perpendicular to the applied force to measure the coincident transverse Poisson s strain and to temperature compensate the primary active gauge the gauge mo
22. in fact a Quarter Bridge Type II circuit and the quarter bridge formulation applies Note further that the quarter bridge technique cannot be used in applications where the direction of the stress field is unknown or changes If there is any force applied in the direction of the dummy gauge then the measurement of strain along the direction of the active gauge will be in error In either case solving for the resultant strain of the Quarter Bridge Type or Type II configuration will yield the following expression note the absence of Poisson s Ratio amp 4Vr 1 RI Rg GF 1 2Vr Half Bridge Equations A Half Bridge uses two active gauges to make strain measurements and has the following general configurations Half Bridge Type Uniaxial Strain Solving for the resultant strain of the Half Bridge Type configuration yields the following note that Poisson s ratio is present where the transverse strain is considered E AVr 1 RI Rg GF 1 y 2Vr y 1 The Half Bridge Type circuit uses two active gauges in a uniaxial stress field with one gauge aligned in the direction of the applied strain and the other gauge aligned in the transverse direction and subject to Poisson s strain The Half Bridge Type circuit is similar to the Quarter Bridge Type II circuit except that in addition to temperature compensating the primary active gauge the gauge mounted in the direction of the applied force
23. ine included Refer to drawing sound wiring and grounding practices may compromise safety and performance S 4501 887 Safety guidelines may require that this device be housed in an approved metal S EXC HALF may jumper to IN 450 1 886A enclosure or sub system particularly for applications with voltages greater than S or IN according to desired or equal to 75V DC or 50V AC polarity of input signal PG 1 2 NOTE The Internal EXCITATION 6 WIRE LOAD CELL 4 WIRE LOAD CELL MILLIVOLT INPUT Terminals Must Be Jumpered To Their Adjacent SENSE Terminals JUMPER re JUMPER 181 amp exc amp Exc S Q sen sen S LOAD CELL LOAD CELL mV S 6 WIRE SN 4 WIRE SN SOURCE S S sen S sen S EXC EXC S JUMPER LS EARTH GROUND Jumper LO See Note 1 uh GROUND l TB2 EARTH GROUND TB2 NOTE rhe Haiti Jumper TB2 Note 1 See Note 1 The Half Bridge Nc 2 m See Nod Nc QN Jumper Is Required To 7 nar Hatr Properly Bias The mV o vc iv NOTE For 4 Wire Load Cells ne Tine Signal Source 2 without sense leads the internal m eo EXCITATION terminals MUST CAUTION Failure eo Milivolt Ranges Set 7 be Jumpered to their adjacent 7 Install The Half Bridge 7 By The Product Of 2 SENSE terminals 2 Jumper Will Result In Ol cana Measurement Error QUARTER BRIDGE HALF BRIDGE FULL BRIDGE USING INTERNAL EXCITATION AND BRIDGE COMPLETION USING INTERNAL EXCI
24. is 20mV at full rated load of 50000psi with 10V of excitation 2 0mV V 10V The output be over driven to 30mV at a load of 75000psi with 10V of excitation safe overload limit Table 3 Summary Of Bridge Types Their Strain Formulation Applications and Wiring ACTIVE GAUGES BRIDGE TYPE N Quarter Bridge Type N 1 Temperature Environments STRAIN FORMULATION PRIMARY APPLICATION AVr 1 RI Rg GF 1 2Vr Uniaxial Compressive Strain In Constant BRIDGE WIRING A Single Gauge Paired With A Matching Resistor and Half Bridge Completion Resistors Quarter AVr 1 RI Rg GF 1 2Vr A Single Gauge Paired With A Transverse Bridge Type II N 1 Uniaxial Compressive Strain With Changing Ambient Environmental Temperatures most common in weigh scale load cells Mounted Dummy Gauge for Temperature Compensation and Half Bridge Completion Resistors Half Bridge Type N 1 y 4Vr 1 RI Rg GF 1 Y 2Vr Y 1 Uniaxial Strain at Higher Stress Levels A Primary Gauge Paired with a Transverse Gauge To Measure Poisson s Strain and Provide Temperature Compensation Requires Half Bridge Completion Resistors Half Bridge Type II N 2 2Vr 1 RI Rg GF 4Vr 1 RI Rg N GF Bending Strain with Two Gauges Subject to Equal and Opposite Strains One Gauge Measures Compression and Other Gauge Measures Tension For Same Applied Force
25. is the excitation voltage measured via an accurate DVM connected across the SEN terminals The software compares this value to its measured value and calculates the corresponding ratio of the resistor divider 9 09K 29 09k Divider Ratio Calibrate Click here store the ratio derived from the Calibration Value in non volatile memory at the module Zero Balance These controls are repeated here for convenience and also appear on the SG Bridge amp Load Cell Calibration Pages Zero Balance controls are provided to correct for any imbalance in the bridge or load cell circuits for the unstrained or unloaded condition Zero Balance Null With no load applied to any element of the bridge or to the loads cell click this button to cause the unstrained or unloaded offset to be determined and to effectively zero the indicated strain IMPORTANT Do not combine tare weight with initial offset Zero Balance Reset Null This value restores the existing bridge offset value to zero IMPORTANT Be sure to invoke Reset Null prior to changing input types between SG Bridge and Load Cells as this offset is stored in microstrain units for bridge inputs and percent for load cell inputs 27 Failure to reset the null value to zero will generate unexpected measurement error if the input type is later changed Zero Balance uStrains or Field This field indicates the current null value or bridge load cell offset
26. like the Type I the Type II does offer temperature compensation Another permutation of this arrangement would have two active gauges in opposite legs of a bridge with equal strains but of the same sign For example these gauges may be mounted on opposite sides of a column with a low thermal gradient Full Bridge Equations The output signal of a half bridge can be effectively doubled by substituting a full bridge A full bridge configuration uses four active gauges to make strain measurements two gauges measure compression and two gauges measure tension If opposing gauges are similarly strained and adjacent gauges oppositely strained the output of the full bridge is twice that of the half bridge and four times that of the quarter bridge Thus the full bridge configuration offers twice the sensitivity of the half bridge but is more expensive due to the two additional gauges Like the half bridge the full bridge is balanced when all gauges undergo the same resistance change It also compensates for changes in temperature The Full Bridge Type circuit has the following configuration Full Bridge Type Bending Torsion Solving for the resultant strain of the Full Bridge Type configuration yields the following expression note the absence of Poisson s strain 6 Vr GF The Full Bridge Type configuration utilizes four active gauges with adjacent gauge pairs subject to equal and opposite strains This confi
27. lt NC Y 1500 D od Y RELAY RELAY OUTPUT DC PI ol he NO POWER o er DIODE DC RELAY POWER D oo D E 46 45 44 Eus um A lt Je JOOOOOOCX Ios FOR VOLTAGE OUT LOCATE RELAY NEAR LOAD OR E 1 222222 GROUND AC POWERED INTERPOSING RELAY mU TYPICAL DIN RAIL MOUNTED RELAY PRONTA Di 46 5 44143 42 41 36 35 34 33 32 31 IY o 5 b a p vom e ales FIGURE B E282 w RELAY OUTPUT PWR D T Cr l 9579 E LA MOV WA AC RELAY POWER lt r LOCATE RELAY NEAR LOAD NOTE ALL RELAY CONTACTS SHOWN IN DE ENERGIZED CONDITION 8 RELAY CONTACT PROTECTION 11 12 13 14 15 16 21 22 23 24 25 26 OA RHRRRRRH RRARRRR FIGURE A DC INDUCTIVE LOADS FIGURE B AC INDUCTIVE LOADS i 1 re2 9S S S SISIS nm TB4 nm TB4 3 3 Hee Ad lt lt seed vov 8 f 1f 1 9 Suc 9 ACV QI nc INPUT CONNECTIONS gt r com A I No e No v SPDT CONTACTS 74 SPDT CONTACTS USE DIODE 1N4006 OR EQUIVALENT USE MOV METAL OXIDE VARISTOR 4501 646B A n I 1 L 1 N RUN 46 45 44 43 42 41 36 35 34 33 32 31 us O Ost re re te lS gt gt T RAIL DIN MOUNTIN aq c mi S EIO DIN EN 50022 35mm O Ory gt E98988E A seas ZIFS RELAY TRIGGER OUTPUT PWR t g Nw O A o9 Veg ee STU O v BRIDGE INPUT COMP SH
28. microstrain units for bridge inputs Failure to reset the null value to zero will generate unexpected measurement error if the input type is later changed Percent The percent field indicates the current null value or load cell offset in percent This value is automatically removed from the measured load and tracked separate from tare Note that large offsets may be indicative of a problem with the load cell Load Calibration Calibration Load This is the known load applied to the load cell in percent of span units Your calibration load should be greater than or equal to 60 of full Scale 28 Load Calibration Measurement Gain This software gain is applied to the measured load to rescale the indicated measurement to match the calibration load during load calibration The Software Gain Factor is set to 1 0 by default but may vary following load calibration You may click Calc Ideal Gain to have the software insert the gain required into this field to equate Input and Calibration Load Load Calibration Input This is the current measured load with Measurement Gain applied It is updated each time the Update button is clicked The idea is to rescale the nput measurement until it converges with the Calibration Load value Load Calibration Calc Ideal Gain Click this button to have the software calculate the ideal Measurement Gain required to equate the current Input measurement with the Calibration Load
29. of control or monitoring system This is especially important where economic property loss or human life is involved It is important that the user employ satisfactory overall system design It is agreed between the Buyer and Acromag that this is the Buyer s responsibility 1 0 INTRODUCTION Series 851T Strain Gauge Transmitters and combination Transmitter Alarms are the newest members of the popular Acromag IntelliPack Transmitter and Alarm Family These instructions cover the hardware functionality of the IntelliPack models listed in Table 1 Supplementary sheets are attached for units with special options or features Table 1 Models Covered in This Manual Input Type Enclosure Approvals Configuration Notes Table 1 1 Agency approvals for CE UL Listed amp cUL Listed Include the C suffix to specify factory configuration option Otherwise no suffix is required for standard configuration 3 Model 851T 0500 units have transmitter functionality only while 851T 1500 transmitters include an alarm relay Module programming transmitter operation and the IntelliPack Configuration Software is also covered in the IntelliPack Transmitter Configuration Manual 8500 570 DESCRIPTION Strain gauges are widely employed in sensors that detect force and force related parameters such as torque acceleration pressure and vibration Strain sensors undergo a small mechanical deformation with an applied force that results i
30. of transmitter zero and full scale plus alarm level and deadband 851T 1500 models is also possible with front panel push buttons and status LED s Front panel push buttons can also be used to reset a latched alarm The alarm relay has a yellow LED on the front of the module that provides a visual indication of the high or low alarm condition Additionally green yellow Status and Zero Full Scale LED s provide local feedback of operating mode system diagnostics and field configuration status All IntelliPack modules contain an advanced technology microcontroller with integrated downloadable flash memory for non volatile program configuration calibration and parameter data storage Once configured these modules may operate independent of the host computer for true embedded monitoring and control The module uses a high resolution low noise Sigma Delta Analog to Digital Converter Z A ADC to accurately convert the input signal into a digitized value An optically isolated Digital to Analog Converter DAC provides the corresponding process current or voltage output A separate alarm circuit controls the relay contacts The input to output transfer function of this transmitter may optionally be configured via a built in linearizer function up to 24 segments The module also includes an input averaging function The output of this transmitter may produce a normal ascending or reverse descending response Model
31. right of this field Bridge Load Cell Signal Range This field displays the product of the excitation and the gauge s rated output all ranges are bipolar It does not include the 5096 over range capability already built in Note that the transmitter output may be separately scaled to utilize only a portion of the available range if so desired Note Large bridge offsets and the inability to precisely tune your selected excitation level can limit the effective input signal range to a value below the nominal range indicated Bridge Load Cell Excitation Source Select Int for Internal default or Ext for External Selecting External will disable the internal adjustable regulator IMPORTANT You must set this parameter to Ext before connecting an external excitation source to the module or damage to the unit s internal excitation supply may occur Note that the new setting is assumed following download Bridge Load Cell Nominal Excitation If the excitation source is set to Internal then this field allows you to specify a nominal excitation level from 4V to 11V typical The actual measured excitation is read back via the remote sense lines and displayed separately on the Test Page Note that the nominal excitation may differ from the measured value due to limitations with adjustment resolution and any larger than expected lead resistance Likewise the firmware may periodically boost the excitation if it drops below le
32. still allowing you to change tare on the fly Shunt Calibration Control Wiring This module includes provisions to accomplish shunt calibration for a shunt calibration resistor located at the module and connected across the bridge resistor via dedicated leads Refer to Drawing 4501 886 12 For convenience you can mount a shunt resistor between the CR and CR B terminals Then connect a switch between the SW terminal and your gauge SW and CR are tied together internally The long leads of the gauge are connected from the opposite end of the switch and the module s CR B terminal This allows you to switch a shunt resistor in and out of the circuit as an aide in rescaling this instrument during shunt calibration Mounting Refer to Enclosure Dimensions Drawing 4501 888 for mounting and clearance dimensions DIN Rail Mounting This module can be mounted on T type DIN rails Use suitable fastening hardware to secure the DIN rail to the mounting surface Units may be mounted side by side on 1 inch centers for limited space applications T Rail 35mm Type EN50022 To attach a module to this style of DIN rail angle the top of the unit towards the rail and locate the top groove of the adapter over the upper lip of the rail Firmly push the unit towards the rail until it snaps solidly into place To remove a module first separate the input terminal block s from the bottom side of the module to create a clearance to the DIN mounti
33. strain simulated via a strain indicator calibrator Typically you would divide the calibrator s dial indication by N to get the actual strain seen by the module with its configuration set to the corresponding bridge type To calculated the simulated strain Es in micro strain units solve the equation above for Es as follows Es micro strain Rg 10 GF N Rs Rg If the lead wire resistance RI is sufficiently large in comparison to the shunt resistance such that 100 RI Rs gt 0 1 required calibration precision in percent then the following calculation for Rs is more precise note the additional term IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Rs Rg 109 GF Es Rg 2 RI To apply these equations it is assumed that the resistance of each leg of the bridge is equal and the bridge is balanced prior to performing shunt calibration Note that the strain simulated by shunting Rg with Rs is always negative compressive and the negative sign is commonly omitted In performing shunt calibration the simulated strain Es is calculated as shown and compared to the actual measured value of the module If the two values differ significantly then the measured response of the module can be rescaled by varying the module s Instrument Gauge Factor or Software Gain until the indicated output properly registers the calculated simulated strain That is the effect of sh
34. successive depression of the UP or DN switch will increment or decrement the output signal by a small amount Holding the switch depressed will increase the amount of increment or decrement 6 Press the SET push button to accept the zero value Note that every time SET is pressed the yellow Status LED will flash once and the zero output will be captured 7 Press the MODE push button one time The yellow Zero Full Scale LED will flash on off indicating that the unit is ready to accept the full scale value equivalent to the scaling input for 10096 output If you do not wish to change this parameter skip to step 11 8 Adjust the input source to the full scale load equivalent the input value must be less than 150 of full rated load and greater than the zero value For our example assume this corresponds to a calibrated load of 100lbs 20mV Note If the zero and full scale points are chosen too close together performance will be degraded 18 Transmitter Alarm Programming Procedure continued 9 Press the UP or DOWN push button once Refer to Functional Block Diagram 4501 885 and note that internally the output of the Range Adjust Box is now set for 100 0 for the input full scale value of 100 100lbs or 20mV The transmitter will adjust it s output to the maximum output value 20 000mA If the output is not exactly at the full scale level 20 000mA press the UP or DN switches continuously un
35. three versions of full bridge are supported also millivolts see below Connections for half and quarter bridge completion are also provided Not suitable for high elongation strain measurements Millivolt Provides input differential leads for connection to a millivolt signal source in range of t5mV to 100mV 100 The millivolt input is set as a Bridge Type selection after selecting SG Bridge as the main Input Type The millivolt range itself is set via the bipolar product of your Gauge Rated Output and Excitation Voltage settings Note that you must also jumper the module s excitation leads to the adjacent sense leads for millivoltage input In addition you must also include a HALF bridge completion jumper to properly bias the input signal source or measurement error will result see Drawing 4501 886 IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input IMPORTANT Complete input connections prior to applying power If the module is powered up prior to completing the input connections the initial self calibration routine will cause an offset error to be generated once the input connections are completed You may correct this error by then resetting the module or cycling the power with complete input connections Input Units SG Bridge input signals are expressed in microstrain units except millivolts Load Cell signals are expressed in percent of span units Millivolt inputs use millivolt units
36. when the carton is opened If the carrier s agent is absent when the carton is opened and the contents of the carton are damaged keep the carton and packing material for the agent s inspection For repairs to a product damaged in shipment refer to the Acromag Service Policy to obtain return instructions It is suggested that salvageable shipping cartons and packing material be saved for future use in the event the product must be shipped This module is physically protected with packing material and electrically protected with an anti static bag during shipment However it is recommended that the module be visually inspected for evidence of mishandling prior to applying power Y CAUTION SENSITIVE ELECTRONIG DEVICES DO NOT SHIP OR STORE NEAR STRONG ELECTROSTATIC ELECTROMAGNETIC MAGNETIC OR RADIOACTIVE FIELDS This circuit utilizes static sensitive components and should only be handled at a static safe workstation INSTALLATION The transmitter module is packaged in a general purpose plastic enclosure Use an auxiliary enclosure to protect the unit in unfavorable environments or vulnerable locations or to maintain conformance to applicable safety standards Stay within the specified operating temperature range As shipped from the factory the unit is factory calibrated for all valid input ranges and has the default configuration shown in Table 2 at right shaded entries apply to alarm equipped Model 851T 1500 WARNING
37. wish to employ the internal half bridge circuit then you must also install a jumper between the TB2 1 IN amp TB2 2 HALF terminals or TB 3 IN amp TB2 2 HALF terminals For quarter bridge completion you will also need to connect an external resistor or dummy gauge near the active gauge as shown in Drawing 4501 887 Refer to Bridge Completion section for more information Millivolt Source If you are using a precision millivoltage Source to simulate a strain gauge input signal or you have selected the millivoltage input range you must also install a jumper between the TB2 1 IN amp TB2 2 HALF terminals to properly bias the input signal Additionally the SEN and EXC terminals are jumpered together and the SEN and IN terminals are jumpered together The millivolt range is the product of the Gauge Rated Output mV V and the excitation voltage settings If simulating a load cell or bridge signal you should also program an excitation voltage equivalent to that desired in your final application as the A D reference voltage is derived from the excitation voltage Optional TRIG Wiring TRIG is an optically isolated digital input that may be used to trigger an auto tare conversion or to alternately reset a latched alarm relay as configured via the IntelliPack software A voltage from 15 30V with respect to COM at the TRIG terminal is sufficient to assert TRIG The tare offset measurement will be subtracted from all s
38. with respect to COM is sufficient to assert the trigger and reset the latched alarm but only if the digital input function has been set to reset latched alarms via the Configuration Software 19 4 0 THEORY OF OPERATION OPERATION OF THE 851T Refer to Simplified Schematic 4501 884 and Functional Block Diagram 4501 885 to gain a better understanding of the circuit This module conditions a single strain gauge bridge input or load cell provides alarm functionality and generates a proportional voltage or current output signal The module uses a differential input channel of an A D to monitor the output signal of a Wheatstone bridge The A D reference voltage is derived from the bridge excitation voltage via a voltage divider across the remote sense signal terminals An adjustable regulator is used to generate the bridge excitation voltage and varies with the setting of a 100 point digital potentiometer The A D input reading is a count value that is a function of the bridge output voltage divided by the A D reference voltage and the A D gain The A D converter performs an analog to digital conversion of the input signal and digitally filters the signal The digitized signal is then serially transmitted to a microcontroller The microcontroller multiplies this count by the A D reference divider 9 09K 29 09K to get the equivalent count of the bridge output voltage divided by the bridge excitation voltage This count is then substituted fo
39. 0 24mA 0 10V DC Output Temperature Drift Better than 20ppm C Typical 50ppm C Maximum Output Conversion Rate Every 120ms or 8 conversions per second maximum Output Response Time Less than 280ms typical to within 0 1 of transition 0 10V into 10KQ Response time will vary with output type and load RELAY OUTPUT SPECIFICATIONS Output Relay 851T 1500 Units Only One independent Single Pole Double Throw SPDT Form C electromagnetic dry contact sealed relay Note to control a higher amperage device such as a pump an interposing relay may be used see Drawing 4501 646 Electrical Life CSA Ratings 25VDC 5A 10 operations resistive 48VDC 0 8A 10 operations resistive 150VDC 0 4A 10 operations resistive 150VAC 5A 3x10 operations resistive Contact Material Silver cadmium oxide AgCdO Initial Dielectric Strength Between open contacts 1000VAC rms Expected Mechanical Life 20 million operations External relay contact protection is required for use with inductive loads see Contact Protection Drawing 4501 646 Relay Response No Relay Time Delay Relay contacts will switch within 280ms for an input step change from 10 of span on one side of an alarm point to 5 of span on the other side of the alarm point ENCLOSURE PHYSICAL SPECIFICATIONS See Enclosure Dimensions Drawing 4501 888 Units are packaged in a general purpose plastic enclosure that is DIN rail mountable for flexib
40. 02 10 0 030V The A D reference voltage is 9 09 29 09 10V 3 125V The ideal gain is Vref Range 3 125 0 030 104 but is limited to the nearest available gain of the A D or 64 from 1 2 4 8 16 32 or 64 The A D will return a count value according to the formula for bipolar mode Count 32768 Vin Gain Vref 32768 Thus a full scale input of 20mV will generate an internal count of 46190 from 32768 64 0 02 3 125 32768 The effective resolution is derived as follows Load Cell Input Type The 0 100 span is 46190 32768 or 13422 Thus the internal resolution for this case is 1 part in 13422 0 007496 However the actual display resolution for this example is limited to two digits after the decimal point if expressed in percent or 0 01 SG Bridge Input Type From the bipolar mode equation Vin Vref Count 32768 32768 Gain and Vref 9 09 29 09 Vexc Thus Vin Vexc 9 09 29 09 Count 32768 32768 Gain and this is the Vr term of the strain equations for a balanced bridge Thus for a quarter bridge with Rlead 0Q strain 4 Vr GF 1 2Vr or 3982 microstrain at 20mV 100 Thus the effective internal resolution is 1 part in 3982 or 0 025 Note that the actual display resolution is 1 microstrain If the SG Bridge was a Full Bridge Type I the strain 999 microstrain and the effective resolution for our example is reduced to 1 part in 999 Response Time Measurement 120ms typic
41. 4 R1 R1 R2 R4 R3 R4 Vex Note that when R1 R2 R4 R3 the voltage output will be zero and the bridge is said to be balanced Thatis it is not required that R1 R4 and R2 R3 to achieve balance just that the ratio of R1 to R2 and R4 to R3 be equal this allows you to use bridge completion resistors that may have a different value than your nominal strain gauge resistance For simplicity of illustration if all four of the resistances in each leg of the bridge are equal then the output voltage measured across the bridge will be zero and the bridge is said to be balanced Likewise any change in resistance in any leg of the bridge will unbalance the bridge and produce a non zero output voltage Note also that the same output can be obtained from two different sets of adjacent resistances as long as their ratios are equivalent R1 R2 R4 R3 Recall if R1 R2 R4 R3 then the output will be zero and the bridge is balanced A negative change in bridge output voltage will result from a decrease in R1 or R3 decreasing R1 R2 increasing R4 R3 Likewise a positive change in bridge output voltage will result by a decrease in R4 or R2 decreasing R4 R3 increasing R1 R2 With the bridge output polarity shown a decrease in resistance R4 will produce a positive change in bridge output voltage The equivalent strain of a decrease in R4 resistance will be negative The general convention is that positive strain is tensile and negative stra
42. Acromag 9 IntelliPack Series 851T Transmitter and Combination Transmitter Alarm Strain Gauge Input USER S MANUAL ACROMAG INCORPORATED 30765 South Wixom Road P O BOX 437 Wixom MI 48393 7037 U S A Tel 248 624 1541 Fax 248 624 9234 Copyright 2001 Acromag Inc Printed in the USA Data and specifications are subject to change without notice 8500 676 D04M013 IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Safety Summary Symbols on equipment Means Caution refer to this manual for additional information The information contained in this manual is subject to change without notice Acromag Inc makes no warranty of any kind with regard to this material including but not limited to the implied warranties of merchantability and fitness for a particular purpose Further Acromag Inc assumes no responsibility for any errors that may appear in this manual and makes no commitment to update or keep current the information contained in this manual No part of this manual may be copied or reproduced in any form without the prior written consent of Acromag Inc Table of Contents Page 1 0 INTRODUCTION DESCRIPTION He Key IntelliPack 851T Features ACCESSORY ITEMS IntelliPack Configuration Software IntelliPack Seria
43. FI EMI ESD EFT and surges plus low radiated emissions per CE requirements e Convenient Mounting Removal amp Replacement The DIN rail mount and plug in type terminal blocks make module removal and replacement easy High Resolution Precise A D Conversion Transmitters include a high resolution low noise Sigma Delta Analog to Digital Converter Z A ADC for high accuracy and reliability High Resolution Precise D A Conversion Output is driven via a high resolution low noise Sigma Delta Digital to Analog Converter 5 DAC for high accuracy amp reliability LED Indicators A green LED indicates power A yellow status LED will turn on if input signal is out of the calibrated range A yellow alarm LED indicates when a relay is in alarm These LED s also have other functions in field program mode A zero full scale LED is used to calibrate transmitter zero and full scale values e Automatic Self Calibration Self calibration is built in to correct for errors due to temperature drift Additional Features Of Model 851T 1500 w Alarm Option e Alarm Functionality 1500 Units Only May be programmed for limit alarms with deadband latching non latching contacts and failsafe non failsafe operation Digital Input Provides Wired Reset for Latched Alarms This module contains a digital input channel that can be used to remotely reset a latched alarm relay High Power SPDT Relay Contacts Includes a Singl
44. FOOT CABLE amp lt MODEL 5030 902 SERIAL PORT ADAPTER MATES TO THE DB9P CONNECTOR AT THE SERIAL PORT OF THE HOST COMPUTER SERIES 8XXT COMPUTER CONNECTIONS HALF BRIDGE COMPLETION TB1 Connections MODEL 5030 913 TO INTELLIPACK CABLE MODULE CONFIGURATION SEEUSER S MANUAL CABLE SCHEMATIC AB REFERRED TO AS REVERSE TYPE INTELLIPACK 5V 1 1 MODULE DOUT 2 2 DINP 3 3 4 4 RST 5 5 COM 6 6 The Internal Half Bridge Uses Two Precision 2 0K Ohm 0 1 Resistors With Low 10ppm C TC amp Ratio Matched to 0 02 4501 643A QUARTER BRIDGE COMPLETION External Wired Half Bridge TB1 Connections The Internal Half Bridge Uses Two Precision 2 0K Ohm 0 1 Resistors With Low 10ppm C EXC TC amp Ratio Matched to 0 02 D SEN 2 Pte 7 lt 2K SEN IN Active lt o 2K gt eo Internal IN T 2 IN Half Bridge Gage 7 gt o IN Internal _ SEN 2 SEN 2 Half Bridge 0 Ea EXC e Dummy i aN 2 OKI eg Gage RM 7 External TB2 Connections Wired Half Bridge XT EF e A Dummy Strain Gauge Should TB2 Connections 2o IN Note That The Internal Half Be Used To Complete The Bridge IN JUMPE
45. Next click Update to download the Measurement Gain to the module and take a new Input measurement Load Calibration Update Click this button to download Measurement Gain to the module and take an input measurement with the Measurement Gain applied You would then compare the resultant Input value to the Calibration Load value and vary the Gain Factor as required until the Input is equivalent to the Calibration Load Measurement Gain effectively rescales the module s indicator by applying gain to the internal result Analog Output Configuration Output Calibration The configuration software can be used to calibrate the output conditioning circuit of this module DAC A slide control is provided on the Output Calibration page to Set the output to its respective low or high endpoint A DVM is then used to measure the corresponding output current or voltage and this measurement is entered into the low or high calibration value field Click on Calibrate to set the low or high endpoint For best results calibrate the Low value before the High value You may also click on Restore Factory Calibration to return the output calibration to its initial factory calibration Notes IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input COMMON MODE EXCITATION ISOLATION VEXC lt ISOLATED POWER EXC SUPPLY 10 36V DC COMMON MODE 5V EXC SEN SIMULTANEOUS RATIOMETRIC
46. OUTPUT type Excitation Level Output Trim Z amp FS i T fer Functions Configuration Software or Input Averaging Linear Proportional Module Push Buttons z Linearizer Normal Reverse Acting gt BRIDGE INPUT 2 Wa Percent EXCITATION 0 to 100 SENSE INPUT Counts ANALOG OUTPUT SENSOR Input Sensor Types INPUT BLOCK Full Bridge Half Bridge Quarter Bridge Bridge Offset Tare Offset Measurement Gain Instrument Gauge Factor Percent Output Ranges Configuration Software RANGE ADJUST OUTPUT BLOCK 0 10V DC or 0 5V DC or BLOCK 0 20mA DC 4 20 mA DC or 0 1mA DC 4501 885A 29 IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input PERSONAL COMPUTER RUNNING WINDOWS 95 OR NT ATTACH ADAPTER TO COM1 OR COM2 ON THE PC PC RUNNING COM PORTS ARE SOFTWARE CONFIGURED ACROMAG CONFIGURATION SOFTWARE 10 TO 36VDC POWER Acromag RUI Os O RELAY LED YELLOW RUN PWR LED GREEN STATUS LED YELLOW s ZEROJ FS LED YELLOW wove MODE SWITCH UP RESET SWITCH Ov DOWN RESET SWITCH O ser SET SWITCH CONFIGURATION PORT FOR RJ11 JACK INTELLIPACK 6 CONDUCTOR SERIAL ADAPTER RJ11 PLUG TT RJ11 PLUG 6 CONDUCTOR 6 CONDUCTOR 6
47. R C 2 HALF Bridge May Be Jumpered To And Should Be Mounted Near 2 HALF IN Either IN Or IN Accordin The Active Gauge To Minimize g Add Jumper Wire Between 2 To Desired Bridge Output Polarity Unwanted Temperature Effects UNE TB2 1 IN amp TB2 2 HALF 2 NOTE The HALF Jumper Is Also JUMPER o Note That The Internal Half Bridge To Use Internal Half Bridge Required To Properly Bias The Add Jumper Wire Between May Be Jumpered To Either IN To Complete External Input When Using A Millivoltage TB2 1 IN amp TB2 2 HALF o Or IN According To Desired Half Bridge See Note LL ___ Source To Simulate A Bridge Signal To Use Internal Half Bridge Bridge Output Polarity ig 851T 0500 851T 1500 BRIDGE COMPLETION CONNECTIONS Sense Leads Sample The Excitation Level At The Bridge And Form The Ratiometric A D Converter Reference Voltage Small Sense Lead Currents Less Than 0 5mA Make Sense Lead Resistance Insignificant High Impedance Differential Input Makes Input Lead Resistance Insignificant Excitation Lead Currents Up To 120mA Must Consider Lead Resistance And Corresponding Drop In Excitation Voltage At The Bridge A Second Input Of The A D Monitors The The Excitation Voltage Level And The Corresponding A D Reference FULL BRIDGE CONFIGURATION WITH EXTERNAL EXCITATION External Wired Full Bridge TB1 Connections FULL BRIDGE CONFIGURATION USING INTERNAL EXCITATION External Wired Full Bridge
48. RENT RL a 12 TO 36VDC TRIG Voltage Yd OUT LOAD E A jumper is required V 04 N C LOAD S Nc between output I and Relay lt JMP for voltage output em me S SPDT CONTACTS Renate this Juniper EARTH Connections Digital Input 9 it S no GROUND 8517 1500 gt Note f L for current output LL 6 See Drawing 4501 646 for SEE RELAY amp DIGITAL RELAY CONNECTIONS interposing relay connections TB4 INPUT CONNECTIONS EARTH lt 7 SHUNT CALIBRATION CONNECTIONS RUNPWRLED GREEN RUM STATUS LED YELLOW 46 45 44 43 42 41 36 35 34 33 32 31 T OQ Qs gheet p EXCITATION KS exce O Rv Hel RELAY LED YELLOW BoesesB8BEg Elgg EDI EE SENSE 29 ZERO FULL SCALE SENSE O repens RELAY TRIGGER OUTPUT j move MODE SWITCH BRIDGE S n IT _ SENSE S sen Oa UP RESET SWITCH A EXCITATION F Exc Ov DOWN RESET SWITCH EARTH GROUND 7 Note 1 nc In SET SWITCH NC HALF ENNE BRIDGE INPUT COMP SHUNT TO BRIDGE SW Nc N CONFIGURATION PORT FOR ERES 2g af oS m oe MO MODULE CONFIGURATION xiz 5 Baeziib5t CR L SEE USER S MANUAL _ m J 11 12 13 14 15 16 21 22 23 24 25 26 SHUNT p RE RES Rs _ __ REMOVABLE TB2 PLUG IN TYPE 12121212212 212121021212 TERMINAL BLOCKS NOTE 1 This ground connection is recommended for
49. TATION AND BRIDGE COMPLETION USING INTERNAL EXCITATION TBi 1 TBi QUARTER BRIDGE EXCH S EXE HALF BRIDGE EXCH SS EXE a EXCITATION Sexe SEN SEN S S SEN f MEN ME BRIDGE Sv BRIDGE N DUMMY i 1 SEN SEN SENSE GAUGE exc 5 RE exc S 7 EXCITATION sen ea gt ALS t ALS S EARTH EARTH EARTH GROUND 182 LA eed JUMPER Te GROUND 2 Note 1 S S Note 1 NC m Add Jumper for Half Bridge S Add Jumper for Half Bridge S Nc HALF completion and if using a S completion and if using a S Remove the HALF jumper for N millivoltage signal source S millivoltage signal source S sensors that already complete 2 drive the input The internal Half to drive the input The internal Half their bridge external to the module S Bridge is ratio G Bridge is ratio 2 S matched to 0 02 S matched to 0 02 o NOTE 1 This ground connection is recommended for best results However if sensors are inherently connected to ground use caution and avoid making additional ground connections which could generate ground loops and measurement error NOTE 2 Be sure to complete input connections prior to applying power or resetting the module IMPORTANT EXTERNAL EXCITATION Module Excitation Terminals MUST be jumpered to their adjacent sense terminals for sensors utilizing external excitation WARNING You MUST turn OFF the internal e
50. This value is automatically removed from the indicated measurement and tracked separate from tare Note that large offsets may be indicative of strain gauge or load cell problems Strain Gauge Bridge Calibration Parameters The information of this page is not applicable to Load Cell Input Types Bridge Calibration Zero Balance These controls are provided to correct for any imbalance in the bridge circuit for the unstrained or unloaded condition Be sure to perform Zero balance prior to shunt calibration The initial bridge offset is the output voltage of the bridge with no applied stress Due to slight differences in the bridge elements and variations in application real bridge circuits are rarely balanced in the unstrained condition and this offset must be accounted for via zero balance Reset Null This value restores the existing bridge offset null value to zero IMPORTANT Be sure to invoke Reset Null prior to changing input types between SG Bridge and Load Cells as this offset is stored in microstrain units for bridge inputs and percent for load cell inputs Failure to reset the null value to zero will generate unexpected measurement error if the input type is later changed Null With no load applied to any element of the bridge click this button to cause the unstrained bridge offset to be determined and to effectively zero the indicated strain IMPORTANT Do not combine tare weight with initial offset uStrains Th
51. UNT iA T goz 209 m zs en amp bizshgu Basis NO 11 12 13 14 15 16 21 22 23 24 25 26 Y Z T T T T Y Y 3 90 ey ean S i J 4 35 gt 110 5 NOTE ALL DIMENSION ARE IN INCHES MILLIMETERS SCREWDRIVER SLOT FOR REMOVAL FROM T RAIL INTELLIPACK TRANSMITTER ENCLOSURE DIMENSIONS 4501 888A 32
52. additional details of the internal bridge type the gauge factor or a materials Poisson s ratio as may be required for strain gauge bridge inputs Only the rated output and nominal excitation are considered for load cells On the other hand bridge inputs will use microstrain units and the formulation for strain is more complex and will require knowledge of these parameters and their application Bridge Inputs The IntelliPack Configuration Software supports strain formulation for all quarter half and full bridge types described above The following information is included to alleviate some of the confusion encountered in selecting the proper strain formulation for bridge input applications Note that all inputs to the 851T module are wired as complete full bridge circuits with remote sense lines included The number of active gauges their purpose and whether bridge completion is already provided or done internally will determine the applicable strain formula In any bridge configuration it is the number of active load cells in the bridge that determine whether it is a half quarter or full bridge Additionally the specific bridge type is determined by considering the mounting of any additional load cells in the bridge i e their purpose the presence of a dummy gauge and whether or not half bridge completion resistors are provided Thus the first step to determine which bridge type applies to your application is to know
53. ain gauges with opposite legs combined such that two legs are in compression and two legs in tension This forms a full bridge circuit that has double the sensitivity of the half bridge circuit and four times the sensitivity of the quarter bridge circuit Solving for the sensitivity of the full bridge application shown above yields Vo Vex GF Effectively twice that of the half bridge circuit The equations presented so far have been simplified in that they assume an initially balanced bridge that generates zero output when no strain is applied This is rarely achieved in practice where resistance tolerances and strain errors induced by the application will almost always result in an initial offset voltage unstrained Further these equations also fail to account for the lead wire resistances in the connections to the excitation supply and the measurement leads The following section reviews permutations of the three basic bridge configurations just presented that take into account the effects of unbalanced bridges lead wire resistance and the coincident Poisson s Strain where applicable STRAIN GAUGE EQUATIONS The following terms and nomenclature are used in the subsequent strain equations for the various bridge configurations is a new term that is used to account for the non balance condition of most unstrained bridges Bridge Output Voltage The convention used in this document assumes that a positive bridge volta
54. al Analog Output 280ms typical to within 0 1 of the final value for a step change in the input This assumes input averaging is set to 1 response time will increase as the input averaging number is increased See Relay Response Time for alarm output response Input Filter Bandwidth 3dB at 30Hz typical IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Noise Rejection Normal Mode 6dB 60Hz typical Noise Rejection Common Mode Better than 120dB 60Hz typical with 1000 input unbalance Analog to Digital Converter A D 16 bits X A converter Input Conversion Rate Every 120ms or 8 conversions per second maximum Input Filter Normal mode filtering plus digital filtering optimized and fixed per input range within the X A ADC Digital Input TRIG COM The trigger input provides connections for a voltage signal to drive the input of an optocoupler in series with an internal series 6 65KQ 0 125W resistor A 200ms minimum voltage pulse from 15 30V DC with respect to COM at TRIG is sufficient to assert the input and remotely trigger a tare offset conversion or optionally reset a latched alarm relay The operative function of TRIG is set to control tare by default but can be configured as a latch reset via the IntelliPack Configuration Software ANALOG OUTPUT SPECIFICATIONS These units contain an optically isolated DAC Digital to Analog Converter that provides a process cur
55. also be installed between the output I and JMP terminals for voltage output remove this jumper for current output Voltage 0 to 10V DC 0 to 5V DC Current 0 to 20mA DC 4 to 20mA DC or 0 to 1mA DC Output Mode Select a normal acting ascending or reverse acting descending output response Strain Gauge Bridge Load Cell Setup Bridge Type Conversion Not Applicable for Load Cell Select from two versions of Quarter Bridge input conversion two versions of Half Bridge input conversion and three versions of Full Bridge inputs or millivolts A graphic of the bridge type will be displayed including reference designators and the applicable strain formula Note The selection of quarter or half bridge types will also require installation of the HALF jumper at TB2 if internal half bridge completion resistors are used Millivolt inputs will also require that this jumper be installed In addition quarter bridge conversion also requires the installation of an external IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input resistor or dummy gauge not supplied See Bridge Completion section for additional details Bridge Load Cell Rated Output Enter the rated output of the bridge or load cell as specified by the manufacturer in millivolts per volt of excitation The product of the rated output and the excitation will determine your signal range The resultant Range is indicated to the
56. and useful over a broad range of applications The safe compact rugged reconfigurable and reliable design of this transmitter makes it an ideal choice for control room and field applications Custom IntelliPack configurations are also possible please consult the factory Key IntelliPack 851T Features e Agency Approvals CE UL Listed amp cUL pending Easy Windows Configuration Fully reconfigurable via our user friendly Windows 95 98 2000 or NT IntelliPack Configuration Program Key IntelliPack 851T Features continued Fully Isolated The analog input digital input power output and relay contacts are all isolated from each other for safety and increased noise immunity e Self Diagnostics Built in routines operate upon power up for reliable service easy maintenance and troubleshooting Nonvolatile Reprogrammable Memory advanced technology microcontroller with integrated non volatile downloadable flash memory allows the functionality of this device to be reliably reprogrammed thousands of times Convenient Field Reprogrammability This unit allows transmitter zero and span calibration plus alarm setpoint and deadband adjustments to be made via module push buttons and LED s thus facilitating in field changes without having to connect a host computer Field adjustment of tare offset is also possible via the digital input TRIG e Wide Range Strain Gauge amp Bridge Inputs Can be confi
57. application SENSOR CALIBRATION The IntelliPack Configuration Software also includes controls to null bridge offsets and perform shunt calibration Additionally controls are provided for adjusting the excitation level setting tare and calibrating the output Only the controls unique to this model are reviewed in the following paragraphs Refer to the Transmitter Configuration Manual for information on controls and adjustments common to all IntelliPacks Bride Balancing Offset Nulling Vost bridge circuits fail to output exactly O volts with no strain applied Slight variations in resistance among each arm of a bridge and between the leads will contribute to some initial unstrained offset voltage This offset may also be due to thermoelectric voltages generated in the circuit wiring or via external noise sources The IntelliPack Configuration software includes software controls to null bridge offsets to zero For example you can null compensate your bridge or load cell by taking an initial measurement before strain is applied to your system then clicking the Input Null button of the software to store the unstrained non zero output signal This offset will be subtracted from subsequent signal measurements until a new Null Offset voltage is stored or the software Reset Null function is invoked Note that input Null automatically subtracts any current non zero offset before writing a new value to the module However this is only ap
58. ation Rescaling the instrument by varying its Gain or Instrument Gauge Factor allows us to account for these errors and more accurately reflect the strain IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input During shunt calibration the strain measurement is modified by varying the Instrument Gauge Factor until the reading matches a pre calculated simulated strain The calculation of the simulated strain is driven by the Gauge Factor of the strain gauge itself and a fixed gain of 1 The instrument s indicated strain is driven by the Instrument Gauge Factor and the Measurement Gain Initially the Instrument Gauge Factor is set equivalent to the Strain Gauge Factor but may differ following shunt calibration Thus the Instrument Gauge Factor is an arbitrary transfer coefficient that can be changed on the fly to convert the input signal to an accurate indicated strain at the module Any changes to the Gauge Factor must also be followed by changes to the Instrument Gauge Factor IMPORTANT The Instrument Gauge Factor of this module is initially set equivalent to the strain Gauge Factor which is initially set to 2 000 by default Thus the indicated strain measurement will be considered equivalent to the measured strain for a strain gauge factor of 2 However if the strain gauge factor GF 2 and its value changes the Instrument Gauge Factor must also change or the indicated strain will be in error The Instrum
59. balance usually remains constant for the measuring system For these reasons it is usually more convenient to keep tare offsets separate from bridge offsets and this module provides separate controls for both If your bridge imbalance is especially large you may wish to determine if the offset is indeed due to a bridge imbalance or to some other external effect like thermoelectric voltage or noise If you simply remove the excitation from the bridge the bridge output should be zero If the bridge output indicated is non zero with no applied excitation and if this value is significant then this output is unrelated to the strain measurement and some effort should be made to identify and remove the source of this error Note however that the 851T performs a ratiometric conversion of the bridge output and the A D reference is generated from the excitation supply Thus the excitation voltage must be present between the remote sense leads SEN SEN to make a measurement That is you can disconnect the EXC and SEN terminals from the bridge but you must keep the EXC wires connected to their adjacent SEN terminals to complete the circuit assuming internal excitation Additionally the bridge completion jumper must be present to properly bias the resultant floating bridge signal Any resultant non zero signal measurement under these conditions can be then attributed to other external effects Shunt Calibration Shunt calibration is a proces
60. citation terminals of the module as the indicated Actual Value has been reduced by the effective line drop since it is taken remotely from the bridge via the SEN lines Likewise a larger than expected lead resistance due to long leads or thin gauge wire may prevent the module from achieving higher excitation levels and the actual value measured here may differ from the nominal value programmed Test Tare Tare is the common element of your input measurement that is to be subtracted from subsequent input measurements It is commonly used to omit the weight of a container The auto tare value is determined by clicking the Tare button which equates the current input measurement to tare If Manual Man tare is selected a tare value may be typed directly into the tare field in microstrain or percent units according to input type Then click Tare to store the value entered 26 Tare can also be updated by remotely triggering a tare conversion via the TRIG digital input of this module Note Tare offsets are handled similar to the initial bridge offsets and may include the initial offset if the separate null offset value is reset or set to zero Tare and initial offset adjustments are kept separate for your convenience to allow you to consider the initial offset and tare weight separately Test Reset Module Clicking on this button will cause a System reset of the module which has the equivalent effect of a power on reset T
61. controls to perform shunt or load calibration and controls to restore the original factory input or output calibration in case of error Provides controls to adjust the bridge excitation voltage Provides controls to null initial bridge or load cell offsets Provides controls to perform shunt or load calibration to re scale the instrument s indicator by modifying its gain and or instrument gauge factor Provides controls to trigger a tare conversion of the input signal can also be done remotely via wired digital input 24 Provides controls to reset a module and reset a latched alarm a latched alarm may also be reset remotely via wired digital input or locally via front panel push buttons Provides a control to adjust a transmitter s output signal independent of the input signal e Allows optional user documentation to be written to the module Documentation fields are provided for tag number comment configured by location and identification information This information can also be uploaded from the module and printed via this software e Allows a module s complete configuration to be printed in an easy to read two page format including user documentation The following transmitter and alarm attributes are configurable via the IntelliPack Configuration Software The descriptions provided are organized with respect to their appearance in the corresponding configuration pages of the IntelliPack Software Yo
62. ction to an external excitation supply IMPORTANT Do not connect the input terminals to any external excitation voltages unless you have first used the Configuration Software to turn the internal excitation supply OFF Failure to follow this procedure may damage the internal excitation supply Input Tare Auto tare is built in and can be triggered remotely via the TRIG digital input 200ms minimum active low pulse or via controls of the IntelliPack Configuration Software Auto Tare is commonly used to remove the weight of a container from a load cell measurement The equivalent tare is automatically removed from subsequent input measurements until TRIG is asserted again later to trigger a new tare conversion The Tare offset takes effect immediately but is only written to non volatile EEPROM memory after 10 seconds of TRIG input inactivity This is done to preserve the life of the EEPROM while still allowing tare to change on the fly Note that tare measurement is not inclusive of itself and does not include any prior tare offset General Input Specifications Accuracy Ambient Temperature Effect Better than 0 01 of input span per 100 or 1 0uV C whichever is greater Resolution The effective resolution will vary according to your rated output mV V excitation voltage and input type selection For example with an excitation voltage of 10V and a rated output of 2mV V the internal range is 150 or 1 5 0 0
63. e Pole Double Throw SPDT electromechanical alarm relay for switching voltages to 230VAC at currents up to 5A Failsafe or Non Failsafe Relay Operation May be configured for failsafe or non failsafe relay operation Configurable Setpoint With Deadband Includes programmable deadband to help eliminate relay chatter and prolong contact life Configurable Latching or Momentary Alarms May be configured with an automatic alarm reset or a latching alarm with manual push button or software reset Configurable Relay Time Delay Filters Transients Useful for increased noise immunity and to filter transients ACCESSORY ITEMS The following IntelliPack accessories are available from Acromag Acromag also offers other standard and custom transmitter and alarm types to serve a wide range of applications please consult the factory IntelliPack Configuration Software Model 5030 881 IntelliPack alarms and transmitters are configured with this user friendly Windows 95 98 200 or NT Configuration Program This software package includes the IntelliPack Alarm Configuration Manual 8500 563 and IntelliPack Transmitter Configuration Manual 8500 570 These manuals describe software operation and various alarm and transmitter functions in detail The Configuration Software also includes an on line help function All transmitter and alarm functions are programmable and downloadable to the modules via this software Non volatile memor
64. e measurement Note that the relative accuracy of your module is strongly dependent upon the accuracy of this measurement Divider Calibration Must Follow Reference Calibration An internal divider is comprised of precision 0 196 resistors and connected across the excitation supply voltage at the SEN terminals in order to generate the A D reference The reference error due to the initial tolerance of these resistors can be accounted for by precisely measuring the excitation voltage across the SEN and SEN terminals then loading this value into the module via the Configuration Software The module will compare its own internal calculation of the excitation voltage with your measured value and then make adjustments to the divider ratio as required Simply measure the excitation voltage across the SEN terminals then input your measured value into the Divider Ratio Calibration Value field of the Input Calibration screen Then click on the Calibrate button to store this value The new ratio will be indicated Again note that the relative accuracy of your module is strongly dependent on the accuracy of this measurement Excitation Voltage Calibration The internal excitation supply is varied via the resistance of a digital potentiometer tied to an adjustable regulator This pot has an initial tolerance of 20 which will cause the upper endpoint of the excitation to vary between 11 and 15V 14 As such the excitation endpoints mu
65. e Poisson s strain an arrangement common to column stress applications Note that one half of the The Full Bridge Type III configuration is used for axial strains where four active gauges are used with one opposite leg gauge pair mounted to measure the tensile strain and the other pair of opposite leg gauges are mounted in a position to measure compressive Poisson s strain for the same applied stress Instrument Gauge Factor The Gauge Factor of a strain gauge is a characteristic transfer coefficient that relates the resistance change in a strain gauge to the actual strain that produced it Specifically the Gauge Factor is the ratio of the fractional change in resistance to the strain GF R R AL L R R 8 The Gauge Factor for metallic strain gauges is typically around 2 0 but may vary with temperature strain level and gauge mounting and this variation will contribute to error in making strain measurements The concept of Instrument Gauge Factor is provided as an additional means of rescaling an instrument s strain measurement system via the process of shunt calibration The other means of rescaling the instrument is by varying its measurement Gain set to 1 by default The need to rescale an instrument is largely driven by the inherent lack of precision in the strain gauge parameters as well as variations in its application For example the rated output mV V of a strain gauge may vary by as much as 10 from the specific
66. e ambient temperature is relatively constant However it is not recommended for real world applications as it does not compensate for changes in temperature For the Type configuration the adjacent resistor in the lower arm is selected to have the same resistance as the strain gauge R3 Rg The two resistors in the opposite legs must be equal to each other R1 R2 but do not have to be equal to the gauge resistor Quarter Bridge Type II Compressive Strain The second configuration Type II is commonly used to measure compression and you may find this type of bridge configuration in weigh scale applications This configuration uses a single active plus a passive or dummy gauge mounted transverse to the applied strain The dummy gauge doesn t measure any strain it is provided for temperature compensation only That is the applied strain has little effect on the dummy gauge as it is mounted in the transverse perpendicular direction the Poisson s Strain is very small but the ambient temperature will affect both gauges equally Since both gauges are subject to the same temperature the ratio of their resistances are the same and Vo does not change with respect to temperature Note that the temperature compensated Quarter Bridge Type II is sometimes incorrectly referred to as a half bridge configuration due to the presence of the second gauge But since the second gauge does not measure strain it is not active it is
67. e below 1200 down to 83O Lower bridge impedance may cause the excitation supply to thermal limit Storage Temperature 40 C to 85 C 40 F to 185 F Relative Humidity 5 to 9596 non condensing Power Requirements 12 36V DC SELV Safety Extra Low Voltage 11 5VDC minimum Current draw is a function of supply voltage excitation current output load and circuit load relay energized SPA connected Currents indicated in Table 8 assume the bridge excitation is driving 10V into 1200 83mA the voltage output circuit is at 10V into 1KO 10mA the relay is energized 851T 1500 only and the Serial Port Adapter is connected An internal diode provides reverse polarity protection CAUTION Do not exceed 36VDC peak to avoid damage to the module Table 8 851T Supply Current Supply 8511 0500 851T 1500 Relay Energized 315mA 350mA Note Supply current will be significantly reduced by reducing the excitation current and or disconnecting the Serial Port Adapter IMPORTANT Do not power up or reset the module without first completing the input connections or the internal self calibration routine will generate an input offset error If this occurs reset the module or cycle power once the input wiring is complete to re invoke self calibration IMPORTANT External Fuse If unit is powered from a supply capable of delivering more than 1A to the unit it is recommended that this current be limited via a high surge tolerant
68. e effect of the shear or Poisson s Strain These devices are commonly referred to as bonded metallic or bonded resistance strain gauges The foil grid is bonded to a thin backing material or carrier which is directly attached to the test body As a result the strain experienced by the test body is transferred directly to the foil grid of the strain gauge which responds with a linear change or nearly linear change in electrical resistance As you can surmise properly mounting a strain gauge is critical to its performance in ensuring that the applied strain of a material is accurately transferred through the adhesive and backing material to the foil itself Most strain gauges have nominal resistance values that vary from 30 to 30000 with 1200 3500 and 10000 being the most common The relationship between the resultant fractional change of gauge resistance to the applied strain fractional change of length is called the Gauge Factor GF or sensitivity to strain Specifically the Gauge Factor is the ratio of the fractional change in resistance to the strain GF R R AL L The Gauge Factor for metallic strain gauges is typically around 2 0 However it is important to note that this ratio will vary slightly in most applications and a method of accounting for the effective Gauge Factor of a strain measurement system must be provided see Instrument Gauge Factor In the ideal sense the resistance of a strain gauge s
69. e factor setting of 2 0000 Table 3 Shunt Resistor amp Simulated Strain Quarter Bridge 1200 Gauges 3500 Gauges Microstrain Microstrain 59 8 ue 174 ue 100 ue 500 ue 299 ue 872 ue 500 ue 1000 ue 598 ue 1744 ue 1000 2000 pe 1197 pe 3476 2000 3000 2978 ye 4000 pe 3000 ue 5000 pe 4000 ue 8510 pe 5000 10000 ue 10000 ue Shunt 1MO 3496500 200KQ 1746500 100KQ 871500 50KQ 579830 434000 346500 20KQ 171500 1MQ 5998800 200KQ 1198800 100KQ 59880Q 50KQ 298800 20KQ 198800 148800 118800 58800 Excitation Level Adjustment This module employs a ratiometric input conversion method that derives the A D reference voltage from the variable excitation voltage level As a result an indicated strain will remain relatively constant as the value of the excitation voltage is changed The output of a bridge is directly proportional to the bridge excitation voltage Normally the highest adjustment of bridge excitation voltage should be used while taking into account the gauge manufacturer s recommendations and the negative effect of self heating in the bridge resistors The internal bridge excitation supply of this model can be adjusted from roughly 4V to 10V at the bridge and is driven via an adjustable regulator whose output is controlled via a 100 value digital pot The excitation level at the bridge is sensed via the remote sense lines to the bridge SEN and
70. e microstrains field indicates the current null value or bridge offset This value is automatically removed from the measured strain and tracked separate from tare Note that large offsets may be indicative of strain gauge problems Bridge Calibration Calibration Element This specifies the bridge element R1 R2 R3 or R4 that is to be shunted to accomplish shunt calibration or instrument scaling Selection of R1 R2 R3 or R4 will require a shunt resistance to be applied across that element of the bridge Bridge Calibration Software Gain Factor This software gain is applied to the measured strain to rescale the indicated measurement to match the internally calculated simulated strain during shunt calibration The Software Gain Factor is Set to 1 0 by default but may vary following shunt calibration A similar effect to varying the Software Gain Factor can be achieved by varying the reciprocal term Instrument Gauge Factor instead as required to re scale measured strain Utilizing the Software Gain Factor to re scale your measurements will allow you to keep the Instrument Gauge Factor equivalent to the strain Gauge Factor if so desired Bridge Calibration Instrument Gauge Factor The instrument gauge factor is normally set equivalent to the strain Gauge Factor per the manufacturer s specification The Instrument Gauge Factor is used to generate the indicated measured value This value may be varied slightly to rescale and modi
71. e offset operations via the configuration software by combining the offset s with field zero calibration up to 2096 of full scale Tare offset generation may also be accomplished in the field via the digital input trigger see Electrical Connections Note If no buttons are pressed for a period greater than 3 minutes the module will automatically revert to run mode green Run LED will light and no changes will be made to the zero full scale and optional setpoint amp dropout settings REMOTE FIELD TARE OFFSET ADJUSTMENT An optically isolated digital input is provided on this module that may be wired to remotely trigger a tare offset conversion or to alternately reset a latched alarm relay 851T 1500 units only The operative function of this active high input is defined via the Configuration Software By default this input is set to function as a trigger for tare offset conversions as described here Auto tare allows the cancellation or taring of any non zero dead weight or other sensor offsets from input measurements It is commonly used to remove the weight of a container from a load cell measurement but could also be used to correct for imbalances in the input bridge if the bridge offset is set to 0 Note that this module handles bridge and load cell offsets separate from tare but the effect of both operations is similar Normally tare is easily accomplished by clicking on TARE of the Configuration Software Tes
72. ent Gauge Factor is normally set equivalent to the Gauge Factor then fine tuned via shunt calibration You need to be aware that changes in Gage Factor only drive the calculation of simulated strain but changes in the Instrument Gauge Factor drive the module s indicated strain Alternately the IntelliPack Configuration Software includes a Software Gain Factor that may be used to directly scale the indicated strain to the simulated strain during shunt calibration The Software Gain Factor is initially set to 1 0 by default but may be varied as required to rescale strain measurements following shunt calibration Note that with respect to the display of strain for bridge inputs via this module the formulas presented are used internally by this module except Instrument Gauge Factor is substituted for Gauge Factor and the result is multiplied by a software Gain Factor for rescaling purposes default gain is 1 000 Determining Your Sensor Type This module supports two input types strain gauge bridge inputs for advanced strain measurement or load cells for basic force measurements Examples of load cell inputs include pressure transducers torque converters accelerometers and vibration sensors These devices may operate under compression and or tension and yield bipolar or unipolar millivolt signals proportional to the applied force Load cell signals are expressed in percent of span units for this module and do not require you to know any
73. er To Drawing 4501 887 This model includes two precision 2KQ 0 1 low TC 10ppm half bridge resistors that are ratio matched to 0 02 plus jumper terminals to facilitate bridge completion for half amp quarter bridge applications Quarter bridge completion will also require that an external wired resistor or dummy gauge not supplied be installed close to the active gauge Refer to Drawing 4501 887 for examples of these types of connections There are two industry conventions with respect to the polarity of the bridge output voltage and the bridge completion resistors of this module may accommodate both Recall that a positive strain is tensile and a negative strain is compressive With the bridge polarities illustrated and the bridge completion jumper taken to the IN lead a positive strain will correspond to a negative bridge output voltage and this is the convention assumed in this manual However with the bridge output polarity flipped and the bridge completion jumper taken to the IN lead instead a positive strain will correspond to a positive bridge output voltage and this is an alternate industry convention Connect the HALF terminal to the adjacent IN or IN terminal as required for your application IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input For half and quarter bridge completion connect a jump wire from TB2 2 HALF to TB2 1 IN or TB2 3 IN as required for your appl
74. est Input 1 This area of the Test screen displays the nominal input range the input value in percent or microstrain and the averaged input value with over sampling Test Xmtr This area of the Test screen displays the scaled output value in percent and the computed value in engineering units volts mA Test Output 1 This is a slide control that can be used to temporarily control the output signal irrespective of the input The current output range and value are also indicated here Module Calibration Note that Calibration of the Divider Ratio should follow calibration of the Reference Voltage Calibration of Excitation is independent of the Reference Voltage amp Divider Ratio Excitation Voltage This calibration is done by measuring the voltage across the sense terminals of the module at the minimum and maximum excitation adjustment limits then downloading the measured value to the module The module uses the endpoint information to calculate the incremental voltage step for the adjustable excitation supply span 99 Simply click on 1 Min Exc Voltage or 1 Max Exc Voltage to set the excitation supply to its minimum or maximum detent Then measure the voltage across the SEN terminals with an accurate DVM and enter this value voltage into the Calibration Value field Next click 2 Calibrate to store the respective endpoint IMPORTANT For best results the excitation supply should be loaded as required by t
75. fy the indicated strain measurement to match the simulated strain while performing shunt calibration IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Bridge Calibration Shunt Resistance This is the value of the shunt resistor in ohms applied across the bridge calibration element specified Enter your shunt resistance and click on Update to cause the software to calculate a Simulated Strain and to simultaneously measure the strain Bridge Calibration Update Click this button to force the software to calculate a simulated strain using the Gauge Factor and the value of Shunt Resistance you have entered and to also take a measurement using the Instrument Gauge Factor and Software Gain Factor you have specified You would then vary your Instrument Gauge Factor and or Software Gain Factor slightly until the Measured Strain converges with the Simulated Strain This effectively re scales the module s strain indicator via shunt calibration Bridge Calibration Shunt Resistor Calc Click this button to have the software calculate the shunt resistor value required to produce the value of Simulated Strain that you have entered in the Simulated Strain Field Bridge Calibration Simulated Strain This value is calculated based on the value of shunt resistance you have specified and the Gauge Factor from the Strain Gauge Setup screen It is updated each time you click Update Alternately you can e
76. ge corresponds to a negative strain indication Vo strained is the bridge output voltage under load Vo unstrained is the bridge output voltage unloaded or initial bridge offset Bridge Excitation Voltage Poisson s Ratio Gauge Factor of Strain Gauge Strain Multiply By 10 for micro strain Vo strained Vo unstrained Vex Nominal Strain Gauge Resistance Lead Wire Resistance Denotes fensile Strain Denotes compressive Strain Poisson s Strain Transverse Strain Common Factor used To Account For Multiple Gauges In A Bridge see Shunt Calibration IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input In the examples presented in this manual for the polarities given it is assumed that a positive strain is tensile and accompanied by a negative bridge output voltage A negative strain is compressive and accompanied by a positive bridge output voltage You can reverse this convention by removing the negative sign from the formulas provided and flipping the polarity of the bridge output voltage Likewise the internal bridge completion resistors may be taken to either IN or IN Quarter Bridge Equations A quarter bridge that uses one active gauge to make uniaxial tensile or compressive strain measurements has the following general configuration Quarter Bridge Type The first configuration Type 1 is most commonly used in experimental stress analysis wher
77. guration is commonly applied to bending beam applications or to shafts under torsion These applications are arranged such that one opposite leg gauge pair is mounted to measure tensile strain and the other opposite leg gauge pair is mounted in a position that causes it to compress for the same applied stress review the balanced beam example for an example of this type of mounting In this configuration the gauges that measure compression are not mounted to measure transverse strain Uniaxial Bending Beam Strain Solving for the resultant strain of the Full Bridge Type II configuration yields c 2Vr GF y 1 The Full Bridge Type II arrangement utilizes four active gauges subject to a uniaxial stress with two gauges aligned to measure the maximum principal strain and the other two aligned to measure the transverse Poisson s strain an arrangement common to bending beam applications Note that one half of the bridge measures the tensile and compressive strains and the opposite half of the bridge measures the compressive and tensile Poisson s strain Full Bridge Type III Uniaxial Column Strain Solving for the resultant strain of a Full Bridge Type 111 configuration yields 2Vr GF Y 1 Vr y 1 The Full Bridge Type III arrangement utilizes four active gauges subject to a uniaxial stress with two gauges aligned to measure the principal strain and the other two aligned to measure the transvers
78. gured for bridge or strain gauge applications from 1mVN to 10mV V e True Ratiometric Input Conversion The A D reference is generated from the excitation voltage and is simultaneous with the input sample optimizing resolution and increasing accuracy This also makes the input measurement relatively immune to errors that result from changes in excitation level Digitally Adjustable Bridge Excitation Constant voltage can be set from 4V to 11V is non volatile and has up to 120mA of drive capability The internal excitation can also be turned OFF for use with external bridge excitation Remote Sense Boosts the excitation voltage at the bridge to prevent lead wire resistance from negatively affecting transducer span or sensitivity Programmed level is continuously closed loop monitored e Automatic Null Compensation Initial unstrained bridge offset voltages can be removed via software control e Automatic Tare Removal Tare weight may be removed via software control or digital input trigger Tare offsets may also be manually written without having to apply a load Digital Input Provides Remote Tare or Alarm Reset An optically isolated digital input is provided to remotely trigger a tare conversion or optionally reset a latched alarm relay These functions can also be accomplished via software push buttons and resetting a latched alarm relay can be accomplished via the module s front panel push buttons Bridge Co
79. he final application before calibrating this supply In addition allow the module to warm up a few minutes prior to calibration Ideally if normal operation takes place at a temperature much higher or lower than 25 C the excitation voltage should be calibrated with the module at ambient temperatures close to the final application Excitation Voltage Low This refers to the minimum excitation output voltage as measured across the SEN terminals under load Excitation Voltage High This refers to the maximum excitation voltage as measured across the SEN terminals under load Excitation Voltage Restore Factory Calibration Click here to cause the module to restore its original factory calibration for the Min Max excitation limits taken with a 3500 load at 25 C IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Reference Voltage Perform Prior To Divider Ratio This calibration is done by measuring the fixed reference voltage connected to channel 2 of the A D and downloading this measurement to the module This reference voltage is nominally 1 225V The module samples this voltage and uses the resultant count to calculate the A D reference level and corresponding excitation voltage level in closed loop fashion Recalibration of this value is normally not required but provided here as a check to correct for component aging or for critical applications that operate at ambient extremes Simply con
80. hould change only in response to the applied strain Unfortunately the strain gauge material as well as the test material it is applied to will expand or contract in response to changes in temperature Strain gauge manufacturers attempt to minimize gauge sensitivity to temperature by design selecting specific strain gauge materials for specific application materials Though minimized the equivalent strain error due to the temperature coefficient of a material is still considerable and additional temperature compensation is usually required THE WHEATSTONE BRIDGE Because strain measurement requires the detection of very small mechanical deformations and small resistance changes the resultant magnitude of most strain measurements in stress analysis applications is commonly between 2000 100006 and rarely larger than about 3000 As such an accurate method of measuring very small changes in resistance is required Likewise this method should also compensate for the strain gauge s inherent sensitivity to temperature This is where the Wheatstone Bridge comes into play The Wheatstone Bridge is comprised of four resistive arms arranged in the configuration of a diamond An excitation voltage is applied across the diamond or bridge input and a resultant output voltage can be measured across the other two vertices of the diamond as shown below R4 R3 From Kirchhoff s Voltage Law and Ohm s Law we can show that Vo VR1 VR
81. ication with respect to the polarity of the bridge output voltage Remove this jumper for full bridge connections Note that the TB2 2 HALF terminal may connect the intersection of the internal half bridge resistor network to the bridge s IN or IN terminal This is done to support the convention of some equipment manufacturer s which may use an alternate relationship with respect to the bridge output signal This is normally apparent by noting the polarity of the lead that the half bridge completion resistors are connected to Where applicable this manual assumes that the half bridge completion resistors are taken to the IN lead and that a negative bridge output voltage will accompany a positive strain If you adopt the opposite convention flip the sign of the strain formulas provided such that a positive bridge output signal will accompany a positive strain IMPORTANT If you are simulating a strain gauge input signal via a precision millivoltage source then you must install this jumper to properly bias the input signal or your measurement will be in error Additionally for quarter bridge completion an external wired resistor or dummy gauge must be installed close to the active gauge to minimize unwanted temperature effects This resistor is usually selected to closely match the active gauge resistance and is typically 1200 3500 or 10000 This resistor is not provided with your module as it must be selected to closely match your
82. in Gauge Factor and a fixed gain of 1 0 and simultaneously sample the input voltage and indicate its measurement using the same parameters except the indicated value is computed with the Instrument Gauge Factor substituted for the strain Gauge Factor and the result is multiplied by the software Gain Factor Typically you would adjust the Instrument Gauge Factor and or Gain Factor as required and again click Update until your indicated measurement closely approximates the simulated value internally calculated Varying the software Gain Factor or Instrument Gauge Factor effectively adjusts the instrument s sensitivity for its indication of relative strain The IntelliPack Configuration Software includes a built in Shunt Resistor Calculator that will calculate a required shunt resistance for a specific simulated microstrain Keep in mind that the accuracy of the resistance and simulated strain calculations diminishes above simulated strains greater than about 2000 microstrain IMPORTANT Shunt Calibration should only be performed on unstrained gauges Bridge offsets should be nulled prior to shunt calibration Always allow the module to warm up several minutes prior to performing shunt calibration 16 The following table lists the simulated microstrain compressive for various resistance values when shunted across the active strain gauge of a quarter bridge circuit N21 for 1200 and 3500 strain gauges These values assume a gaug
83. in is compressive Thus a positive bridge output voltage will result from a compressive stress that decreases resistance R4 which will produce a negative strain This is the convention used throughout this manual If you were to replace R4 in the bridge with an active strain gauge Rg any change in the strain gauge resistance AR will unbalance the bridge and produce a non zero output voltage proportional to the change in resistance Note that the change in resistance due to the applied strain is AR Rg GF IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input If R1 R2 and R3 Rg then substituting Rg R for R4 in our earlier equation for Vo yields the expression Vo Vex GF 4 1 1 2 which is the sensitivity of this quarter bridge circuit The presence of the 1 1 GF 2 term in the this expression is representative of the small non linearity of the quarter bridge output with respect to strain However the effect of this non linearity is generally small and can be ignored for quarter bridge strain levels below about 5000 microstrain Note that the active strain gauge Rg may occupy one leg of a Wheatstone Bridge Quarter Bridge Configuration two legs of a bridge Half Bridge Configuration or four legs of a bridge Full Bridge Configuration with any remaining legs of the bridge occupied by fixed resistors or dummy gauges In any case the number of active gauge
84. ing Rg R3 Likewise a positive change in bridge output results from shunting Rg or R2 decreasing Rg R3 increasing R1 R2 For the polarities shown a positive change in bridge output voltage will result when Rshunt is applied across Rg The resultant strain obtained by shunting Rg with Rs will be negative resistance decreases The general convention is that positive strain is tensile and negative strain is compressive Thus a positive bridge output voltage will result from a decrease in the Rg leg resistance which will produce a negative strain compressive This is the convention used throughout this manual Note that the shunt resistance Rs and simulated microstrain Es are related via the following equation applicable at simulated strains less than 2000 microstrain Rs Rg 10 GF N Es Rg In this equation Rg is the resistance of the shunted gage arm typically the nominal bridge resistance i e 1200 3500 or 10000 N is a factor used to account for the presence of multiple active gauges in a bridge circuit see table below Es refers to the simulated strain in microstrain units and its sign is omitted Note that GF refers to the Gauge Factor of the strain gauge and not the Instrument Gauge Factor used by the module Quarter Bridge Type amp 11 Half Bridge Type I Half Bridge Type II Full Bridge Type II amp 1 Full Bridge Type Note that the factor N can also be used to correct the
85. l Port Adapter IntelliPack IntelliPack Software Interface Package INTRODUCTION TO STRAIN THE WHEATSTONE BRIDGE STRAIN GAUGE 2 0 PREPARATION FOR USE UNPACKING AND INSPECTION INSTALLATION Jumper Installation For Voltage Output Only Bridge Completion Jumper Installation Remote Tare Shunt Calibration Control Wiring Mounting aieo actae dete esed AREE Electrical Connections 3 0 CALIBRATION AND ADJUSTMENT MODULE SENSOR FIELD CONFIGURATION AND ADJUSTMENT REMOTE FIELD TARE OFFSET ADJUSTMENT REMOTE FIELD RESET OF LATCHED ALARMS 4 0 THEORY OF OPERATION 5 0 SERVICE AND REPAIR SERVICE AND REPAIR ASSISTANCE PRELIMINARY SERVICE PROCEDURE 6 0 SPECIFICATIONS MODEL NUMBER INPUT SPECIFICATIONS
86. l correspond to a negative bridge output voltage Load Cell Inputs A simpler form of the Wheatstone bridge is the load cell The load cell is a device principally used in weighing systems that utilizes strain gauge technology internally Unlike the strain gauge the output of a load cell will be expressed in equivalent units of force not microstrain As a result processing a load cell signal does not require intimate knowledge of its bridge type gauge factor or Poisson s ratio Rather the important considerations of a load cell are its rated output mV V its excitation and its rated capacity Note that even though the load cell itself will contain permutations of quarter half or full bridges this detail is irrelevant and rarely provided by the manufacturer Further most load cells have bridge completion and temperature compensation already built in Example 1 A compression load cell has six connection wires sense excitation and signal and is specified as follows Rated Capacity 50 000 Ibs inches Full Scale Output 2 0mV V Rated Excitation 10V DC 15V Maximum Safe Overload 150 Full Scale Operating Temperature Range 65 F to 200 F From these specifications we can conclude the following This load cell is temperature compensated wide ambient The cell already includes half bridge compensation resistors internally note the wiring most common for this cell type The output of this load cell
87. latched alarms If the alarm is latching it is recommended that the deadband be set to a minimum IMPORTANT Noise and or jitter on the input signal has the effect of reducing narrowing the instrument s deadband and may produce contact chatter Another long term effect of contact chatter is a reduction in the life of the mechanical relay contacts To reduce this undesired effect increase the deadband setting IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Visual Alarm Indicator A yellow LED labeled RLY for the relay provides visual status indication of when the relay is in alarm LED is ON in alarm This LED is also used in field configuration mode to indicate whether setpoint or deadband is being adjusted Relay Time Delay Programmable from 0 milliseconds to 4 seconds in 200ms increments for this model typically used to help filter input transients and avoid nuisance alarming A minimum delay of 200ms default is recommended for increased noise immunity and enhanced conformance to applicable safety standards This delay does not apply to control of the transmitter s analog output only the relay Relay Operating Mode User configurable for failsafe operation relay deenergized in alarm state or non failsafe operation relay energized in alarm state Failsafe mode provides the same contact closure for alarm states as for power loss while non failsafe mode uses alarm contact c
88. le high density approximately 1 wide per unit mounting Dimensions Width 1 05 inches Height 4 68 inches Depth 7 4 35 inches see Drawing 4501 888 DIN Rail Mounting xx0x DIN rail mount Type EN50022 rail 35mm Connectors Removable plug in type terminal blocks Current Voltage Ratings 15A 300V Wire Range AWG 12 24 stranded or solid copper separate terminal blocks are provided for input power output amp relay contacts For supply connections use No 14 AWG copper wires rated for at least 75 C Case Material Self extinguishing NYLON type 6 6 polyamide thermoplastic UL94 V 2 color beige general purpose NEMA Type 1 enclosure Printed Circuit Boards Military grade FR 4 epoxy glass Shipping Weight 1 pound 0 45 Kg packed IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input APPROVALS CE marked EMC Directive 89 336 EEC UL listed UL3121 First Edition CUL listed Canada Standard C22 2 No 1010 1 92 Product approval is limited to general safety requirements of the above standards Warning This product is not approved for hazardous location applications ENVIRONMENTAL SPECIFICATIONS Operating Temperature 25 C to 70 C 13 F to 158 F with external excitation or with internal excitation and bridge impedance greater than or equal to 350Q Limit maximum ambient to 60 C with bridge impedance below 3500 down to 1200 and 50 C with bridge impedanc
89. losure opposite to power loss conditions Relay Reset The relay may be configured to automatically reset when the input retreats past its setpoint and deadband or the relay may latch into its alarm state Use the up or down push buttons on the front of the module to reset a latched relay and exit the latched state this may also be accomplished under software control A latched relay may also be reset remotely via the digital input of this module when this input has been separately configured as a latched alarm reset Test Page Tools This page of the IntelliPack Configuration Program provides tools for communicating with and controlling your module This page also displays a graphic of the front panel of the module with LED status included The following functions and controls are supported Test Polling Click On to enable continuous polling of the module The green status LED should blink while polling is enabled Test Excitation Because of the limited resolution of the adjustable excitation supply 100 points the programmed nominal excitation level Set Value can only be approximated to within the span of adjustment divided by 99 divisions 93mV typical The Actual Value indicates the value obtained through a closed loop read of the excitation voltage at the bridge via remote sensing This is also the value used for internal calculations Note that the Actual Value may not be equivalent to the value measured at the ex
90. mpletion Module has built in precision ratio matched half bridge resistors and jumper terminals to accomplish half to full and quarter to full bridge completion The polarity of the bridge output may be varied by taking the bridge completion resistors to IN or IN e 24 Segment Linearizer Optionally the I O transfer function may be configured via a 24 segment linearizer Averaging may also be applied to the linearizer function Universal Analog Output Supports process current output ranges of 0 20mA 4 20mA and 0 1mA and 0 5V or 0 10V outputs Current outputs drive up to 5500 typical Voltage outputs include short circuit protection Normal Or Reverse Acting Output Direction The analog output of this transmitter may be software configured for a normal ascending or reverse descending response e Wide Range DC Powered Unit is powered via 12 36V DC supply and the power terminal is series diode coupled providing reverse polarity protection This also makes this transmitter compatible with systems that use redundant supplies and or battery back up IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Key IntelliPack 851T Features continued e Wide Ambient Operation The unit is designed for reliable operation over a wide ambient temperature range Hardened For Harsh Environments The unit will operate reliably in harsh industrial environments and includes protection from R
91. n a small change in resistance proportional to the applied force They are commonly wired using the Wheatstone bridge whose resultant output voltage is directly related to the resistance in each leg of the bridge and the bridge excitation voltage These models provide a single ratiometric input for interface to strain gauge sensors wired in Wheatstone bridge format or to 6 wire load cells The output of this transmitter is an isolated process current or voltage proportional to the measured strain Optionally the output includes an isolated Single Pole Double Throw SPDT electro mechanical alarm relay Model 851T 1500 The module also includes an adjustable regulated bridge excitation supply Remote sensing provides lead wire compensation and will boost this voltage level as necessary so that the programmed excitation is applied at the remote sensor The differential input conversion is ratiometric making input measurements immune to changes in the excitation voltage Sensor lead break detection is also provided Provisions for half and quarter bridge completion are built in An isolated digital input is included for remotely triggering a tare conversion or to optionally reset a latched alarm relay Units are reconfigured calibrated and interrogated via our easy to use Windows 95 98 2000 or NT IntelliPack Configuration Program IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input In field reconfigurability
92. n of the excitation voltage range by 99 divisions The embedded configuration and calibration parameters are stored in non volatile memory integrated within the micro controller However only the functions required by an application are actually stored in memory new functionality can be downloaded via the IntelliPack Configuration Software and the Serial Port Adapter A wide input switching regulator isolated flyback mode provides an isolated excitation supply isolated 14V output circuit supply and isolated 5V circuit power Refer to Functional Block Diagram 4501 885 for an overview of how the software push button configuration variables are arranged IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input 5 0 SERVICE AND REPAIR CAUTION Risk of Electric Shock More than one disconnect switch may be required to de energize the equipment before servicing SERVICE AND REPAIR ASSISTANCE This module contains solid state components and requires no maintenance except for periodic cleaning and verification of configuration parameters zero full scale setpoint deadband etc Since Surface Mount Technology SMT boards are difficult to repair it is highly recommended that a non functioning module be returned to Acromag for repair The board can be damaged unless special SMT repair and service tools are used Further Acromag has automated test equipment that thoroughly checks and calibrates the pe
93. nd does not require bridge completion If your bridge has four active gauges with one half of the bridge adjacent gauge pair mounted to measure the tensile and compressive strain and the opposite half mounted to measure the coincident transverse Poisson s Strains then you would select a Full Bridge Type Il formulation This type is commonly used to measure the uniaxial stress in bending beam applications This arrangement is inherently temperature compensated and does not require bridge completion If your bridge has four active gauges with one diagonal gauge pair mounted to measure the principal tensile strain and the opposite diagonal gauge pair mounted to measure the transverse compressive Poisson s Strain then you would select a Full Bridge Type Ill formulation This type is commonly used to measure the uniaxial stress in a column This arrangement is inherently temperature compensated and does not require bridge completion Table 3 below summarizes each of the bridge configurations discussed along with their respective strain formulation applications and wiring These equations apply for the bridge output voltage in the polarity shown Where applicable if the bridge completion resistors connect to IN instead of IN you effectively flip the polarity of the bridge output voltage and you may remove the negative sign preceding each equation The convention illustrated in this document assumes a positive strain is tensile and wil
94. nd are provided Controls for field tare offset generation and the remote reset of latched alarm relays are also provided The operation of these controls are described in the following paragraphs MODULE CALIBRATION The IntelliPack Configuration Software includes calibration controls for reference voltage and divider calibration plus excitation endpoint calibration These adjustments have already been performed at the factory and readjustment may not be required except as necessary to verify operation or to satisfy your company s maintenance requirements This module uses a ratiometric conversion method in which the A D reference voltage is derived from a voltage divider connected across the variable excitation supply Thus the input signal is sampled simultaneously ratiometric to the reference when the input is wired as a Wheatstone Bridge That is the input signal and the A D reference are both directly proportional to the bridge excitation voltage A second A D channel samples a fixed internal reference voltage and uses the resultant measurement to precisely determine the programmed excitation level IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input This software includes controls for calibrating this reference calibrating the bridge excitation voltage span and for calibrating the resistor divider applied to the bridge excitation voltage that is used to generate the A D reference Provisions for acc
95. nect a DVM across the two post vertical header installed on the circuit board and enter the DVM measurement into this field This requires that the cover be removed temporarily use strict ESD handling procedures to make this measurement and avoid damage to the module Click Calibrate to store this value Reference Voltage Instructions Click here for instructions on how to perform this calibration Reference Voltage Calibration Value Enter the value measured with an accurate DVM connected across the two post header of the circuit board cover removal required 1 224V to 1 226V typical Reference Voltage Calibrate Click here to store the Calibration Value in non volatile memory at the module Divider Ratio Calibrate Reference Voltage First This calibration is done by measuring the excitation voltage across the SEN terminals with a DVM then downloading this measurement to the module The module uses this information to precisely determine the ratio of the divider that is connected across the excitation supply and used to derive the reference to the A D Note that the divider is formed with precision 0 1 25ppm C resistors between the SEN terminals Divider Ratio Instructions Click here for instructions on how to perform this calibration Divider Ratio Ratio This field indicates the current divider ratio stored in the module obtained from the last upload Divider Ratio Calibration Value This
96. ng area Next insert a screwdriver into the lower arm of the DIN rail connector and use it as a lever to force the connector down until the unit disengauges from the rail Electrical Connections Input output power amp relay terminals can accommodate wire from 12 24 AWG stranded or solid copper Strip back wire insulation 1 4 inch on each lead before installing into the terminal block Input wiring should ideally be shielded twisted pair Since common mode voltages can exist on signal wiring adequate wire insulation should be used and proper wiring practices followed It is recommended that transmitter output and power wiring be separated from the input signal wiring for safety as well as for low noise pickup Note that input power output and relay terminal blocks are a plug in type and can be easily removed to facilitate module removal or replacement without removing individual wires If your application requires voltage output you must install a jumper between the output I and JMP terminals this jumper is installed at the factory and should be removed for current output applications Always remove power and or disable the load before unplugging terminals to uninstall the module installing or removing jumpers or before attempting service All connections must be made with power removed CAUTION Risk of Electric Shock More than one disconnect switch may be required to de energize the equipment before servicing
97. nter a value of simulated strain and click on Shunt Resistor Calc to estimate the resistor required to produce the value of simulated strain you entered Bridge Calibration Measured Strain This value is measured each time you click Update and is calculated from the input signal using the Instrument Gauge Factor amp Software Gain Factor you have specified You vary the Instrument Gauge Factor and or Software Gain Factor to make this value converge with the Simulated Strain value during Shunt Calibration Load Cell Calibration Parameters The information of this page is not applicable to strain gauge bridge Input Types Load Calibration Zero Balance These controls are provided to correct for any initial load cell offset in the unloaded state Null With no load applied to the load cell click this button to cause the unloaded bridge offset to be determined and to effectively zero the indicated load IMPORTANT It is recommended that you not combine tare weight with initial offset as this module provides controls to adjust each separately Reset Null This value restores the existing load cell offset value to zero This should be done prior to changing input types as the offset is stored in percent for load cell inputs and microstrain units for bridge inputs IMPORTANT Be sure to invoke Reset Null prior to changing input types between Load Cell and SG Bridges as this offset is stored in percent for load cells and
98. omplishing shunt calibration are also provided IMPORTANT Allow the module to warmup several minutes prior to perfoming calibration If the internal excitation is used this supply should be loaded with the equivalent resistance of the gauge or load cell prior to calibrating its endpoints Reference Calibration This Calibration Must Be Performed Prior To Divider Cal The A D includes a fixed reference voltage internally connected to channel 2 It periodically samples the channel 2 voltage to derive the excitation level and the corresponding A D reference voltage The initial reference voltage at channel 2 may vary slightly from 1 225V and as a result its voltage must be accurately measured and input to the firmware of the module A small 2 pin header is internally connected across this reference for measurement via a DVM The cover must be removed to gain access to this header Note that this voltage has already been calibrated at the factory and readjustment is not normally necessary CAUTION If you choose to make this readjustment and take this measurement you must use strict ESD handling procedures Otherwise the sensitive internal circuitry could be easily damaged via ESD or an inadvertent short To calibrate this reference precisely measure the voltage across P1 cover removed Type the measured value into the Reference Voltage Calibration Value field of the Module Calibration screen then click the Calibrate button to store th
99. one jack See Drawing 4501 643 for location Configuration information is downloaded from the host computer through one of its EIA232 serial ports This port must be connected to the module through an Acromag IntelliPack Serial Port Adapter This Serial Port Adapter serves as an isolated interface converter between EIA232 and the IntelliPack s SPI port Baud Rate 232 19 2K baud SOFTWARE CONFIGURATION Units are fully reprogrammable via our user friendly Windows 95 98 2000 or NT IntelliPack Configuration Program Model 5030 881 A cable 5030 902 and converter 5030 913 are required to complete the interface Software Interface Package 800C SIP See Drawing 4501 643 In addition to configuring all features of the module the IntelliPack Configuration Software includes additional capabilities for testing and control of this module as follows Monitors the input signal microstrain or percent excitation voltage A D reference voltage and output signal values Also monitors the input type excitation source input sensitivity input range null offset and tare offset Allows polling to be turned on or off e Allows a configuration to be uploaded or downloaded to from the module and provides the means to rewrite a module s firmware if the microcontroller is replaced or the module s functionality is updated Provides controls to separately calibrate the input circuit the output and the excitation supply Also provides
100. plied correctly if the same input type is used bridge or load cell That is if you wish to change input types and you already have a non zero null offset stored then you should click the Reset Null button prior to changing input types or your subsequent measurements will be in error IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input This is because the null offset is stored in the engineering units of the input type bridge types use microstrain while load cells use percent of span Note that an offset null conversion is similar to a tare conversion and null offsets could be conveniently combined with tare but only if you first use Reset Null to set any initial bridge offset to zero However if you choose to combine the unstrained bridge offset with the tare offset then you will not be able to extract the actual tare weight from a measurement Note that tare measurements are typically much larger than bridge imbalances as tare may take any value within the range of the input By combining null with tare a non zero strain will be indicated with no applied stress module indication will not return to zero with the load and tare removed The ability to separate bridge offsets from tare is also useful in judging the operation of a bridge or load cell as large bridge offsets are sometimes indicative of sensor problems Additionally tare may change values frequently for a given load cell while the bridge im
101. r the Vr term of the strain equation and a value of strain as a function of count is calculated This is then converted to strain units bridge inputs or percent load cells and corrected for initial offset and tare to produce a measured strain As the input signal is ratiometric to the A D reference the effect of simultaneously deriving the A D reference from the excitation voltage and measuring the bridge output produces a ratiometric input conversion that is virtually immune to changes in the excitation voltage The microcontroller completes the transfer function according to the input type and its embedded program then sends a corresponding output signal to an optically isolated Digital to Analog Converter DAC The DAC updates its current or voltage output in response The microcontroller also compares the signal value to the limit value according to its alarm type and completes all necessary alarm functions per its embedded program 851T 1500 units only A second A D input monitors a fixed reference voltage in order to obtain the current excitation voltage via closed loop feedback Since the A D reference is related to the excitation voltage by a voltage divider the actual excitation voltage level can then be calculated and verified against the value obtained by multiplying the incremental value by the number of digital pot cycles required to achieve the user specified value the incremental value is obtained by dividing the adjustment spa
102. r the value of Poisson s Ratio for the material that the strain gauge s are applied to if other than 0 285 default value For example the Poisson s Ratio for steel varies from 0 25 to 0 30 Note that this value is ignored for Quarter Bridge Half Bridge Type 11 and Full Bridge Type I applications 25 Transmitter Configuration Transmitter Scaling Scaling is performed after averaging and converts the engineering units of the input range or a portion of the input range to 0 100 at the output That is scaling allows virtually any part of the selected input range to be scaled to 0 and 100 at the transmitter analog output The scaling may also be adjusted in the field via front panel push buttons and status LED s Transmitter Computation The following gives a brief description of the current available transmitter I O transfer functions that can be applied to this model via the Configuration Software None Proportional Default Each input sample is converted into a directly proportional output update Linearizer Permits the entry of 25 user defined input to output break points to facilitate up to 24 segment linearization of a non linear sensor signal End Points Configuration Transmitter Zero Full Scale Input maps to Zero Full Scale Output Alarm Configuration 851T 1500 Model 851T 1500 units may be configured for simple limit alarms You may also refer to the IntelliPack 800A Alarm Family for dedicated ala
103. rce 17 If using a precision millivoltage source to drive the input it is suggested that you also adjust the internal excitation source to a level that will approximate your final application the A D reference is derived from the excitation Prior to field calibration the module s input type bridge configuration excitation level and sensitivity must already be set via the IntelliPack Configuration Software Input levels outside of 150 of full rated load excitation level multiplied by sensitivity will not be acceptable for zero full scale setpoint or dropout calibration Since input levels cannot be validated during field programming entering incorrect signals can produce an undesired output response Install a jumper between the output I and JMP terminals for voltage output remove this jumper for current output Equipment Required A bridge calibrator strain indicator calibrator simulator or weights dummy loads may be used as an input source Optionally a precision millivolt source may also be used to drive the input In any case the resultant signal source must be accurate over the range required for zero and full scale and alarm setpoint and dropout levels Note For best results the input source must be accurate beyond the required specifications An accurate current or voltage meter is also required to monitor the output level Ideally this meter must be accurate beyond the module specifications
104. relay labeled RLY LED s to indicate which parameter is being programmed A constant ON zero full scale LED refers to zero configuration scaling input for 0 output a flashing ON OFF zero full scale LED refers to full scale span configuration scaling input for 10096 output A constant ON relay LED indicates setpoint adjustment a flashing ON OFF relay LED indicates dropout deadband adjustment Refer to Table 4 Table 4 Field Configuration LED Program Indication LED INDICATOR CONSTANT ON FLASHING Yellow Zero Full Scale Zero Full Scale labeled Z FS 851T 1500 Only Yellow Relay High or Low High or Low labeled RLY Setpoint Dropout CAUTION Do not insert sharp or oversized objects into the Switch openings as this may damage the unit When depressing the push buttons use a blunt tipped object and apply pressure gradually until you feel or hear the tactile response IMPORTANT This module performs a ratiometric conversion of the input signal and the A D reference is derived from the bridge excitation voltage via the sense leads Thus the module requires that the excitation and sense lead connections be intact in order to complete a conversion That is simply connecting a millivolt Source to the input in order to simulate a bridge signal will not work without also completing the excitation and sense wiring and installing the half bridge completion jumper at TB2 1 amp TB2 2 to properly bias the input sou
105. rent or voltage output Note that calibration can only occur with respect to one of the outputs voltage or current and only one of the outputs may operate at a time Note For sensitive applications high frequency noise may be reduced by placing a 0 1uF capacitor directly across the load Voltage Output Specifications Output Range 0 10V DC 0 5V DC Output Accuracy See Table 6 Output Current 0 10mA DC maximum Output Impedance 10 Output Resolution See Table 6 Output Short Circuit Protection Included Current Output Specifications Output Ranges 0 20mA DC 4 20mA DC or 0 1mA DC Output Maximum Current 21 6mA typical Output Accuracy See Table 6 Output Compliance 10V minimum 11V typical Output Resolution See Table 6 Output Load Resistance Range 0 to 5500 typical Table 6 Analog Output Range Resolution amp Accuracy Accuracy Output Range Resolution Percent of Span Output Overall 0 to 20mA DC 0 002596 0 025 Notes Table 6 1 Voltage outputs unloaded Loading will add I R error 2 Software calibration produces high accuracy 3 All current and voltage ranges are subsets of the 0 24mA range which provides under and over range capability General Output Specifications Digital to Analog Converter Analog Devices AD420AR 32 16 bit Z A 22 Integral Non Linearity 0 002 1 4LSB of span typical 0 012 7 9LSB of span maximum for ranges utilizing full output span
106. rformance of each module Please refer to Acromag s Service Policy Bulletin or contact Acromag for complete details on how to obtain service parts and repair PRELIMINARY SERVICE PROCEDURE Before beginning repair be sure that all installation and configuration procedures have been followed The unit routinely performs internal diagnostics following power up or reset During this period all LED s will turn ON momentarily and the green Run LED will flash If the diagnostics are successfull the Run LED will stop flashing after two seconds and remain ON indicating the unit is operating normally If the Run LED continues to flash then this is indicative of a problem In this case use the Acromag IntelliPack Configuration Software to reconfigure the module and this will usually cure the problem If the diagnostics continue to indicate a problem via a continuously flashing green LED or if other evidence points to a problem with the unit an effective and convenient fault diagnosis method is to exchange the questionable module with a known good unit The IntelliPack Serial Port Adapter also contains a red LED visible at the small opening in the enclosure to the right of the RJ11 receptacle If this LED is OFF or Flashing and power is ON then a communication interface problem exists Note that the adapter receives its power from the IntelliPack module A constant ON LED indicates a properly working and powered serial interface adapter
107. rigger tare offset generation in the field without limitation via the digital input trigger see Electrical Connections Note The bridge excitation level the gauge rated output and the input type wiring can only be set via the IntelliPack Configuration Program Calibration is optimally performed via the Intellipack Software but field program mode provides an alternate form of input to output calibration by allowing you to scale virtually any portion of the input range to the selected output range via the front panel push buttons and tare generation via the digital input IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input In the following example assume that we are using a 2mV V compression cell rated for full output at 100lbs with nominal excitation of 10V and 50 over capacity Thus this load cell will output 20mV when excited by 10V with 100lbs applied IMPORTANT Field calibration operates on Xmtr Configuration parameters and will change your Input for 0 Output and Input for 10096 Output software parameters As such you should perform tare prior to calibrating the unit via the front panel pushbuttons Transmitter Alarm Programming Procedure 1 Connect your load cell or simulator to the input as required refer to Electrical Connections Drawing 4501 886 Be sure to include the excitation and sense lead connections which are required for ratiometric conversion Also connect a precise c
108. rm modules that support other operating functions Alarm Input The input signal range to the alarm is the full range for the configured input type regardless of the calib rated range If input averaging is used an averaged input value will be used by the alarm Alarm Mode Select a High or Low limit for the alarm function of this model The relay will trip on an increasing input signal for a high limit and on a decreasing input for a low limit Alarm Setpoint A high or low setpoint plus deadband may be assigned to the relay and is programmable over the entire input range The relay will enter the alarm state when either the user defined high or low setpoint is exceeded for the specified amount of time this allows input transients to be filtered Relay remains in the alarm state until the input signal has retreated past the defined setpoint plus any deadband for the specified amount of time Please refer to the IntelliPack alarm family for dedicated alarm modules that support other operating functions Alarm Deadband Deadband is associated with the setpoint and is programmable over the entire input range Deadband determines the amount the input signal has to return into the normal operating range before the relay contacts will transfer out of the alarm state Deadband is normally used to eliminate false trips or alarm chatter caused by fluctuations in the input near the alarm point Note that deadband may also apply to
109. s by which the module s sensitivity is rescaled by adjusting the module s Instrument Gauge Factor and or its Gain such that its indicated measurement matches a calculated simulated ideal strain The term is a misnomer here as it does not actually calibrate the module or the strain gauge but rather the effective sensitivity of the strain measurement system To accomplish shunt calibration a large known resistance value not provided is placed parallel with one of the arms of the bridge to reduce the effective resistance of the arm and simulate astrain Note that the shunt resistor does not necessarily have to shunt the active gauge and in some cases it may be more convenient to shunt another bridge element The magnitude of the response will be the same but the sign of the indicated strain will vary according to the bridge element shunted 15 The shunt will affect the bridge output either positively or negatively depending on the leg of the bridge that is shunted If the measured response is not equivalent to the calculated strain with the shunt applied then the module s sensitivity is typically rescaled by varying the Instrument Gauge Factor and or Software Gain until the two values converge Rshunt R1 R2 R3 Rg From the above figure recall that when R1 R2 Rg R3 the output will be zero and the bridge is said to be balanced A negative change in bridge output will result by shunting R1 or R3 decreasing R1 R2 increas
110. s in a bridge is key to determining whether a bridge is a quarter half or full bridge type Recall that for the bridge circuit above and the polarities set as shown tensile positive strains will produce a positive output voltage if located in cells 1 and 3 and a negative output voltage if located in cells 4 and 2 Compressive negative strains will produce a negative output if located in cells 1 and 3 anda positive output if located in cells 4 and 2 Changes of resistance in adjacent arms of the bridge are subtractive if of the same sign and they tend to cancel each other out If the adjacent cell resistance changes are of opposite sign they are additive Likewise resistance changes in opposite cells are additive if of the same sign and tend to cancel each other out if of the opposite sign Because changes in resistance at adjacent bridge resistors have the same numerically additive effect on the bridge output when those changes are of the opposite sign and have the opposite effect numerically subtractive when changes in adjacent arms are of the same sign then by placing similar gauges and lead wires in adjacent arms and exposing them to the same temperature they act together to nullify their individual thermal effects on the bridge output effectively canceling the temperature induced strain error To illustrate if you use two strain gauges in the bridge the effect of temperature can be avoided Substituting Rg R for R4
111. s with IEC1000 4 2 Level 8KV AKV air direct discharge to the enclosure port and European Norm EN50082 1 Surge Immunity Complies with IEC1000 4 5 Level 3 2 0KV and European Norm EN50082 1 Radiated Emissions Meets or exceeds European Norm EN50081 1 for class B equipment FIELD CONFIGURATION AND CONTROLS Field programming of transmitter zero and full scale all models plus alarm setpoint and dropout levels 851T 1500 only and tare is accomplished with module push buttons and LED indicators Note The unit must be initially configured via the Configuration Software before its configuration can be varied in the field Tare conversion should be done prior to field calibration Module Push Buttons See Dwg 4501 643 For Location Mode Used to change mode of field configuration Set Used to accept input data during field calibration Up Reset Used to increment output level during field calibration Used to reset a latched alarm relay in operating mode Down Reset Used to decrement output level during field calibration Used to reset a latched alarm relay in operating mode TRIG Digital Input Terminals Auto Tare or Latch Reset TRIG Active high isolated digital input trigger used to remotely trigger a tare offset conversion or alternately reset a latched alarm relay A 15 30V voltage from TRIG to COM is sufficient to assert this trigger 6V typical The TRIG terminal has a resistor of 6 65KQ in series with
112. st be precisely calibrated in order for the module to be able to make accurate excitation adjustments to user programmable levels This calibration directly determines the incremental excitation voltage or adjustment resolution 93mV typical which is the span of this adjustment divided by 99 a 100 value digital pot is used For best results the excitation supply should be loaded with the equivalent resistance of your bridge or load cell before taking voltage measurements Likewise allow the module to warm up prior to calibration Note that the excitation supply has already been calibrated at the factory with a 3500 load If your load differs significantly from this you may increase measurement accuracy via recalibration Simply click the Min Exc Voltage button of the Input Calibration screen to send the excitation supply to its minimum point Measure the excitation voltage via a DVM connected across the EXC terminals Type the measured value into the Excitation Voltage Low Calibration Value field then click on the Calibrate button to store the endpoint Repeat this process for the Max Exc Voltage value IMPORTANT If you choose to recalibrate the excitation supply endpoints then you should do this with the excitation supply loaded with the equivalent impedance of your bridge or load cell Allow the module to warmup several minutes prior to calibration Ideally the module should be at an ambient temperature close to that of its final
113. t Page but may be alternately invoked in the field by wiring a voltage signal to the TRIG digital input terminal provided on the module A TRIG voltage from 15 30V with respect to COM is sufficient to trigger a tare conversion of the input but only if the digital input function has been set to control tare The new tare offset will take effect immediately after deasserting TRIG and will be stored in non volatile EEPROM memory only after 10 seconds of TRIG inactivity The tare offset will remain in effect for all input measurements until TRIG is asserted again later or the Tare Reset Tare software buttons are invoked Note however that TARE is not inclusive of itself that is a tare measurement does not include any prior tare offset REMOTE FIELD RESET OF LATCHED ALARMS A digital input channel is provided on the module that may be wired to remotely reset a latched alarm relay or alternately trigger a tare offset conversion described above This input is active high and its operative function is defined via the Configuration Software By default this input is set to function as a trigger for auto tare but may be alternately defined as a reset for a latched alarm relay via the Configuration Software for 851T 1500 models Note that a latched alarm relay can be reset four ways by turning the power off momentarily via software control via the front panel push buttons or remotely via this digital input A TRIG voltage from 15 30V
114. this device is primarily a process transmitter 851T Transmits and isolates a single strain gauge bridge or load cell input signal DC millivoltage X500 The four digits of this model suffix represent the following options respectively X 1 with Alarm Relay X 0 without Alarm Relay 5 Output Transmitter Voltage or Current 0 Enclosure DIN rail mount 0 Approvals CE UL Listed and cUL Listed INPUT SPECIFICATIONS Unit must be properly wired and configured for the intended input type and range see Installation Section for details All inputs to this module must be wired as full bridges with remote sense lines included The unit can be configured to accept any of Seven strain gauge bridge types plus millivoltage or load cell inputs via the IntelliPack Configuration Program The following paragraphs summarize this model s input types ranges and applicable specifications Load Cell Provides input differential leads sense leads remote sense and excitation leads internal variable supply for connection to 6 or 7 wire load cells up to 100mV For connection to 4 wire load cells you must jumper the module s excitation leads to the adjacent sense leads see Drawing 4501 886 SG Bridge Provides input differential leads sense leads remote sense and excitation leads internal variable supply for connection to strain gauge bridges Two versions of quarter bridge two versions of half bridge and
115. til the desired output is achieved You may adjust the output to a level from 60 110 of full scale Note After first pressing the UP amp DN push buttons they will function as trim adjustments for the output stage The maximum output trim adjustment should be limited from 60 to 11096 of the nominal full scale endpoint Each successive depression of the UP or DN switch will increment or decrement the output signal by a small amount Holding the switch depressed will increase the amount of increment or decrement 10 Press the SET push button to accept the full scale value Note every time SET is pressed the yellow Status LED will flash once and the full scale output will be captured 11 If you are configuring an 851T 0500 model which has no alarm function then you should skip steps 12 17 and jump ahead to step 18 12 Press the MODE push button one time until the yellow zero full scale LED goes out and the yellow relay LED turns ON see Table 4 In this mode the unit is ready to accept an input setpoint level for the alarm If you do not wish to change the setpoint skip to step 15 Note The setpoint can be set to any value within the input range regardless of the zero full scale settings 13 Adjust the input source to the High or Low alarm load equivalent For our example assume 110 110lbs or 22mV This is your alarm setpoint level 14 Press the SET push button to accept the setpoint Note that ever
116. u may also refer to the IntelliPack Transmitter Configuration Manual 8500 570 for additional details regarding configuration attributes General Configuration Input Type Select SG Bridge or Load Cell see Determining Your Sensor Type Note that the Strain Gauge Bridge type assumes the input is wired in the Wheatstone bridge format and will express its output in microstrain units The Load Cell type assumes a 6 wire connection to the load cell and will express the output in percent of span units Four wire load cells may be accommodated see Drawing 4501 886 Select SG Bridge if you wish to configure a millivolt input Input Samples Select the number of input samples A D conversions for calculation of an average select 1 default 2 4 8 or 16 before processing the signal Increasing samples is useful for help in filtering transients Note that the effective response time will be increased by the factor selected Both the alarm relay and transmitter output will use the averaged value and their response times will be affected accordingly Input Digital Function 851T 1500 Only Select the functionality of the digital input to trigger tare default or to reset a latched alarm relay The digital input is asserted high by a voltage from 15 30V On 851T 0500 units this input is used only to remotely trigger a tare conversion Output Range Unit can be configured for either a voltage or current output range A jumper must
117. ubsequent bridge or load cell measurements until a new tare conversion is done or the software s Reset Tare button is clicked Optional Shunt Wiring This module includes anchor connections for an external shunt resistor and switch that may be used to enable and disable a shunt element during shunt calibration Refer to Electrical Connections Drawing 4501 886 for examples of these connections 3 Analog Output Connections Wire the output as shown in Electrical Connections Drawing 4501 886 For the voltage output you must also install a jumper between the output I and JMP terminals installed at the factory Remove this jumper for current output Note For sensitive applications high frequency noise may be reduced via a 0 1uF capacitor placed across the load 4 Output Relay Contacts Wire relay contacts as shown in Electrical Connections Drawing 4501 886 See the Alarm Relay Specifications for power capacity 13 If necessary an interposing relay can be used to switch higher currents as shown in the Interposing Relay Connection Drawing 4501 646 Electromechanical Relay Contact Protection To maximize relay life with inductive loads external protection is required For DC inductive loads place a diode across the load 1N4006 or equivalent with cathode to and anode to For AC inductive loads place a Metal Oxide Varistor MOV across the load See Relay Contact Protection Drawing 4501 646 for details
118. unt calibration is to rescale the module s sensitivity and this process is also referred to as Instrument Scaling To accurately perform shunt calibration you should apply the shunt at the bridge and not at the instrument However in some cases it may not be convenient to apply the shunt at the gauge If the shunt resistor is local to the instrument then you must provide separate leads to the bridge resistor that is to be shunted these leads must be of equal length and gauge For your convenience this module provides screw terminals for installation of a shunt calibration resistor plus connections to a switch in order to enable or disable the shunt Refer to Electrical Connections Drawing 4501 886 The IntelliPack Configuration Software provides an entry field for your shunt resistance Rs as well as a field that is used to identify the leg or bridge resistor that is shunted for a specific bridge configuration the calibration element A graphic figure is shown with reference designators for the standard quarter half and full bridge configurations Fields for Instrument Gauge Factor and Software Gain Factor are also provided A calculator is also built in to calculate the required shunt resistance for a specific simulated strain With the shunt resistance applied to the bridge element you simply click the Update button which will use the parameters you provided to calculate a simulated strain this calculation uses the actual stra
119. unted to measure strain in the same direction as the applied force then you would select a Half Bridge Type I formulation This is commonly used to measure uniaxial strains at higher stress levels where the effect of the transverse strain is greater and must be accounted for Note that the Half Bridge Type circuit is similar to the Quarter Bridge Type ll except that the transverse mounted gauge also measures the transverse Poisson s strain as well as temperature compensates the primary active gauge If your bridge has two active gauges with both gauges mounted such that they are subject to equal and opposite strains for the same applied force then you would select a Half Bridge Type Il formulation This is commonly used in bending beam applications where one gauge is mounted in a position that causes it to compress while the other gauge undergoes tension The presence of the second active gauge does provide temperature compensation but does not measure transverse strain Additionally this type will require half bridge completion resistors and these may be wired externally or provided internally via the 851T module IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input If your bridge has four active gauges with adjacent gauge pairs subject to equal and opposite strains for the same applied stress then you would select a Full Bridge Type formulation This arrangement is inherently temperature compensated a
120. urrent milliampmeter or voltmeter to read the output signal from the transmitter 2 Apply power and the module s green Run LED will light 3 Press and hold the MODE push button until the green Run LED turns OFF and the yellow Zero Full Scale LED turns ON In this mode the unit is ready to accept a zero input for the transmitter equivalent to the scaling input for 096 output If you do not wish to change the zero parameter skip to step 7 4 Adjust the input signal to the zero load equivalent this value must be within the range capability of the load cell You may choose an input equivalent up to 20 of full scale For our example assume this corresponds to a calibrated load of 1096 10165 or 2mV 5 Press the UP or DOWN push button once Refer to the Functional Block Diagram 4501 885 and note that internally the output of the Range Adjust Box is now set for 0 0 for the input zero value of 10lbs 2mV The transmitter will adjust it s output to the minimum output value 4 000mA If the measured output is not exactly at the zero level 4 000mA press the UP or DN switches continuously until the desired output is achieved You may adjust the output up to 20 of full scale Note After first pressing the UP amp DN push buttons they will function as trim adjustments for the output stage The minimum output trim adjustment should be limited from about 10 of full scale around the nominal range endpoint Each
121. ust limit your excitation voltage between 4V and 11V DC Do not exceed these limits or damage to the unit may result Keep in mind that the A D reference is generated via the excitation supply and you must complete this circuit by including the EXC and SEN lead connections just as if you were using internal excitation Likewise since the unit no longer has closed loop control of the excitation voltage under these conditions make sure that your supply provides a clean steady voltage to the bridge or measurement accuracy may be compromised AC bridge excitation is not permissible for use with this module WARNING You must use the IntelliPack Configuration Software to turn OFF the internal excitation supply BEFORE you connect the unit to an external excitation source or damage to the unit may result Do not exceed rated excitation voltage limits FIELD CONFIGURATION AND ADJUSTMENT This program mode allows adjustment to key transmitter calibration and alarm parameters in the field without having to connect a host computer Field reprogrammability of zero amp full scale input to output scaling plus alarm setpoint amp deadband Model 851T 1500 is alternately accomplished via this transmitter alarm module s SET MODE DOWN push buttons and the zero full scale and relay LED s see Drawing 4501 888 as described here The following procedure uses the corresponding zero full scale labeled Z FS and
122. vel Bridge Gauge Resistance Not Applicable to Load Cells Enter the nominal gauge resistance as specified by the gauge manufacturer For the purposes of strain calculation it is assumed that all gauges and or resistors of quarter and full bridge applications have the same resistance Bridge Lead Resistance Not Applicable to Load Cells This is the lead resistance of the excitation and sense leads to the gauge in ohms All leads are assumed to be of the same gauge and length Note The excitation supply provides sufficient overdrive voltage to support 10V at the bridge with up to 5O of lead resistance and currents up to 100mA Bridge Gauge Factor Not Applicable to Load Cells Enter the Gauge Factor of the strain gauge as specified by the manufacturer The default gauge factor is set to 2 000 Do not confuse this Gauge Factor with the Instrument Gauge Factor of the module Note that the Instrument Gauge Factor is initially set equal to the Gauge Factor but may vary following shunt calibration The Instrument Gauge Factor is used by this module for calculation of its measured strain The Gauge Factor here is primarily used to calculate the simulated strain during shunt calibration and to set the initial value of the Instrument Gauge Factor The Instrument Gauge Factor may be varied to rescale the indicated strain measurement while holding Gauge Factor constant Bridge Poisson s Ratio Not Applicable to Load Cells Ente
123. xcitation supply prior to connecting an external excitation supply or damage to the unit may occur 91 4501 886A PG20F2 IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input DC POWERED INTERPOSING RELAY INTERPOSING RELAY CONNECTIONS CONTAC J TYPICAL DIN RAIL MOUNTED RELAY PROTECTION
124. y provides program configuration and data storage within the IntelliPack IntelliPack Serial Port Adapter Model 5030 913 This adapter serves as an isolated interface converter between the EIA232 serial port of the host computer and the Serial Peripheral Interface SPI port of the IntelliPack module It is used in conjunction with the Acromag IntelliPack Configuration Software to program and configure the modules This adapter requires no user adjustment no external power and operates transparent to the user It receives its power from the IntelliPack module The adapter has a DB9S connector that mates to the common DBS9P serial port connector of a host computer The adapter also has a 6 wire RJ11 phone jack to connect to the IntelliPack alarm module via a separate interconnecting cable described below Refer to Drawing 4501 635 for computer to IntelliPack connection details IntelliPack Cable Model 5030 902 This 6 wire cable is used to connect the SPI port of the IntelliPack Serial Port Adapter to the IntelliPack This cable carries the SPI data and clock signals reset signal and 5V power and ground signals The cable is 6 feet long and has a 6 wire RJ11 plug at both ends which snap into jacks on the Serial Port Adapter and the IntelliPack module IntelliPack Software Interface Package Model 800C SIP The IntelliPack Software Interface Package combines the Configuration Software 5030 881 Alarm Configuration Manual 8500
125. y time SET button is pressed the yellow status LED will flash once and the value at the input will be captured 15 Press the MODE push button one time and the yellow relay LED should start flashing see Table 4 This means that the unit is ready to accept the dropout level for the alarm relay If you do not wish to change the dropout skip to step 18 16 Adjust the input source to the desired dropout level load equivalent For our example assume 100 100lbs or 20mV 17 Press the SET push button to accept the input dropout level Note that every time the SET button is pressed the yellow status LED will flash once and the value at the input will be captured The module will use the difference between the setpoint and dropout values to calculate relative deadband For our example this is 10 10lbs or 2mV 18 Press the MODE push button one time to complete the program sequence and return to run mode The green RUN LED will turn ON the yellow Zero Full Scale LED will be OFF and the yellow alarm LED will be on or off according to the alarm status The module will now assume a transfer function based on the zero and full scale values just set The setpoint and dropout of 851T 1500 units determines the alarm deadband IntelliPack Series 851T Transmitter Alarm User s Manual Strain Gauge Input Note that field adjustment of zero and full scale can eliminate the need to perform separate null or tar
126. y when subject to an applied force Specifically strain is the fractional change in dimension length width or height of a body when subject to a force along that dimension That is AL L Note that strain can be either positive tensile or negative compressive Further the magnitude of a strain measurement is typically very small and is often expressed as a whole number multiple of 105 or microstrain uE In most cases strain measurements are rarely encountered larger than a few millistrain 10 or about 300048 When a body of material is subject to a force in one direction a phenomenon referred to as Poisson s Strain causes the material to contract slightly in the transverse or perpendicular dimension The magnitude of this contraction is a property of the material indicated by its Poisson s Ratio The Poisson s Ratio Y is the negative ratio of the coincident compressive strain that occurs in the transverse direction perpendicular to the applied force to the strain in the axial direction parallel to the applied force That is Poisson s Ratio Y Likewise the Poisson s Strain y Strain gauges are devices that change resistance slightly in response to an applied strain These devices typically consist of a very fine foil grid or wire grid that is bonded to a surface in the direction of the applied force The cross sectional area of this device is minimized to reduce the negativ

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