Thermocouple monitor and transmitter
Contents
1. have no internal connection elsewhere they are potential free The relays can be used to control a 230 VAC line voltage If one relay is connected to the line voltage then the other must not be used for low voltage circuits for electrical safety reasons Controlling a heavily inductive load will shorten the life of the relays An external snubber circuit is then recommended When this unit has no power supply the relay 2 contacts will be closed ORfunction Connections i There are two 4 3 2 1 4 3 2 alarm relays inside A B the transmitter 682 4 The first relay contacts are F connected in terminals 1 and 2 11213 in connector G G H and the second relay in terminals R 1 2 3 3 and 4 These N gt gt o 09 0 x x Operation RA1 Alarm comparator x4 RA2 gt Alm1 5 Alm2 gt Alm3 Logical alarms gt Alm4 Delay z There is four independent logical alarm comparators that are used to examine a single register e g the input 2 reading whether it is above or below a limit The result is either false 0 or true 1 placed in a register Alm1 Alm4 These do not control any relay yet Moreover the states of the sensor resistance alarms are in registers RA1 and RA2 18 Relay output x2 NO NC x2. NE indicator Relays After the logical alarms have been configured the relays can be programmed to follow those logical alarms or sensor resistance alarms Up to four logical alarms can be defined for a relay If any of them is true the relay will activate The relays have a NO NC normally open closed selection It affects the relay coil only The front panel indicators A1 and A2 tell whether the relay is active that is if any of the logical alarms selected is true and the delay has expired Settings Conf Alarms Alm1 General Alm1 Type Display Alm2 Src Inputs Alm3 Level Math Alm4 Hyst Outputs Rel1 Alarms Relays Src1 Relays Rel1 Src2 Serial Rel2 Src3 Src4 Delay NC There is four identical logical alarms one in each Alm1 Alm4 submenu The first alarm controls the register Alm1 and so on The relays following these alarms are set up in the Rel1 and Rel2 submenus Type Alarms Alm1 Alm4 Alarm type e Off This alarm is not used e Lo Low level alarm Activates if the reading specified at Src setting goes below the Level setting e Hi High level alarm Src Alarms Alm1 Alm4 This defines the register that this alarm investigates E g to have an high level alarm when input 1 exceeds 50 select Src In1 and Lev
3. When a register value is changed this way it is stored in the non volatile EEPROM memory and restored when this transmitter is powered up next time Menu tree The complete configuration menu is shown here to aid navigating The menus are explained in the relevant chapters e General and Display page 9 Inputs page 13 Math page 20 Outputs page 16 Alarms and Relays page 19 Serial page 22 Display Src1 ped Inputs ai Common Common Src2 inf m Speed Dec In2 Sensor Unit Ev MaxRes Differential General ae Lopass Setuptime CfCode pecs Pts Reslnterval EUS Mea1 Recovery ae can AlmDelay Conf Dec4 TE General Ed4 ees Display Inputs Math Math ELo Outputs Outputs Outt ae ae Alarms Out2 Src oe Alm1 Range Serial Aim RI Aim3 Ami Out1 Alm4 Type Rdg2 Relays Sre Out2 Rel1 ae et Break Rel2 Src1 Src2 Serial Src3 Protocol Src4 Address Delay Baud NC Dec 10 INPUTS Connections and jumpers 4 3 2 1 4 3 2 1 A B
4. Inputs Math Math Outputs ELo Alarms Relays Serial Registers The unit has so called registers They are containers where a variable data is stored Some registers are used by the unit to store its readings and the rest are free to be used by the user program See page 6 for more information on the registers The registers are the same that can be seen with the Monitor function that can be accessed from the front panel or the PC configuration software Registers F1 F12 are provided to be used by the user program Other registers than F1 F12 should not be written to Note that these registers can be accessed from the front panel too see Ed settings on page 9 Unless used as an Ed register these are initialized to zero at power up Program structure The program consists of lines Every line has one simple command The command can change a register or cause a conditional jump inside the Data moving and math commands dest src that is called F1 dest src1 src2 dest src1 src2 Subtracts dest src1 src2 Multiplies dest src1 src2 Divides dest srcSQ dest src1 amp src2 If the capabilities offered by the transmitter are not enough they can be extended by writing a custom program inside the transmitter With the ELo programming language it is possible to do calculations conditional execution and timing The program can handle both floating point values and
5. or two known temperatures to the sensor and write down the displayed and the real temperatures Then set Pts to 1 or 2 depending on the number of calibration points and write the first reading in Mea and the real temperature in Scat And the same with Mea2 and Scaz2 if two points are to be calibrated ANALOG OUTPUTS Connections and jumpers Cc O NEZ 50 gt l O00 4 3 2 1 4 3121 i A B Out1 mA E Free Out1 V 6821 Out2 mA Out2 V F Out2 485 1 21314 G H 1 21314 1 21314 j Free eal Free The two analog outputs are provided in the connector B There is five jumpers affecting the analog outputs The first output Out1 can be selected between the mA and V output signals the corresponding Operation The analog output can be programmed to follow either input any built in function or any register including the results of an ELo program A free two point scaling is provided to convert the reading to a physical signal in mA or V Settings The Outputs submenu is further divided in two identical submenus Out1 and Out2 for two analog output channels 16 change must be done in the configuration settings too The second output can be selected among mA V or RS 485 serial output The factory setting is for two mA outputs and no serial communications When the output is con
6. with a low resistance sensor 0 05 rdg 0 5 C lin error thermal drift Thermocouple resistance Range Accuracy Excitation Common A D conversion Speed Warm up time V output Range Accuracy Thermal drift Reading all chs Termination Relays Device unpowered 0 to gt 1000 kohm 10 approx 1 5 pA 16 bits 32767 Configurable 30 min 0 10 V or less 0 005 V 2mvV C after changing settings 300 ms for the next command SCL 100 ms 57600 baud Modbus 30 ms 57600 Jumper selectable None or 110 ohm 1 nF 2 A 250 VAC Relay 1 open 2 closed 24V model Environment Oper temperature Other Weight Mounting Connectors Galvanic isolation Regulations EMC immunity EN 61326 EMC emissions EN 61326 Dimensions il 45 mm 24 V DC AC 15 200 mA 10 60 C 250 g 35 mm DIN rail 2 5 mm detachable Inputs together Analog and serial output together These class B 230V model 85 260 V AC DC 5 W groups and power supply isolated from each other Power up time 1 5 sec Electrical safety EN 61010 1 OOOO 0000 5 8 Qu O F O000 se OOOO OOOO 110 mm 26
7. 6821 F 1 2 3 4 G H 1 2 3 4 1 2 3 4 Input signals are E Free In1 mA In2 mA In2 pint 4w In2 pin1 15V Keep these open connected in connectors F Free and H F is the input 1 and 1 2 3 4 Free E H is the input 2 D Te Connect the positive wire of the thermocouple in Potential equalization The input circuitry is galvanically isolated from the power supply and output circuits However the input channels are not isolated from each other Moreover there is a differential amplifier in the inputs that requires that the potential on the inputs terminals 2 and 3 is near the input circuitry ground terminal 4 With RTD s the differential amplifier input is tied to the input ground via the sensor connections and there is no matter With other inputs the differential amplifier inputs must be tied to the internal ground somehow There is three different ways Internal grounding switch The input terminals 2 and 3 are connected through semiconductor switches to the differential amplifier feeding the analog to digital converter The other channel is separated by open semiconductor switches In the picture there is a thermocouple on both channels as an example There is no external connection to the terminal 4 the input ground The internal grounding switch is enabled by setting Differential to No in the Inputs Common menu terminal 2 and the negat
8. NEL Peel ual state The front panel can be used to monitor the operation of arm teers the transmitter and to change the settings It has several states of operation e Normal state displaying the readings e Configuration state changing the settings e Monitor state displaying the readings and other Select variable data Enter Exit Nokeval 6800 Series Normal state After power up the front panel is in the normal state displaying the input 1 reading unless otherwise set The channel being displayed can be selected using the AY keys While changing the channel the channel name is displayed until the key is released Which channels can be selected depends on the settings Configuration state Entering Press the and 4 keys simultaneously two seconds in the normal state to enter the configuration state When entered the Conf led will light If configuration password is set you will need to enter it now Cod 0 displayed In case the password is not known switch the power off hold the and keys pressed and switch the power on again PWDC is displayed briefly This will also set the serial settings to their default values Navigating The menu is organizated hierarchically You can move within one menu using the AY keys and enter a submenu with the key Returning from a submenu is done with the key See the menu chart on page 10 Editing To see or edit a setting va
9. RAL Mounting This transmitter is intended to be mounted on a 35 the flow of the cooling air and ruin the mm DIN rail It should be installed on a wall as on thermocouple accuracy A small air gap to the next the front cover picture Other positions will affect instrument on the rail is recommended Connections Power supply Outputs O 5 The connectios are explained in the chapters Inputs Q lt E Analog outputs Alarms amp relays Power supply and KS S E c ued iere 9 a 6 FEE Serial communications zo og J55 SSS N 8 666 4066 4 3 2 1 1 4 3 2 1 4 3 2 1 1 4 3 2 1 A A B B F 1 2 3 4 Input 1 G H 1121314 1 2 3 4 Input 2 n Relay 1 Relay 2 Alarm relays mA Jumpers To access the jumpers use a small screwdriver to click the four locks see photo Then pull the top and bottom parts of the case apart The power supply must be disconnected to avoid electric shocks The picture shows the jumper locations and the default setup Jumpers labeled Free can be taken off and used where needed The jumper positions are explained in the chapters Analog outputs and Serial communications pages 16 and 22 respectively Outi mA Mg Free y D Outt V Don t use ow 2 Out2 mA Don t use o a 3 Out2 V Don t use Out2 485 Don t use w Don t use o 485 floating Bo E 485
10. U The reading is always represented with six significant digits except negative readings with five e g pi would be represented 3 14159 After power up before the first reading is finished the transmitter will return NAK 0 message to MEA commands in order to prevent the logger software from logging invalid readings MEA SCAN 1 2 Returns the readings on registers 1 2 separated by one space See MEA CH for data representation MN xxxxx Commands used by the Mekuwin configuration software Modbus protocol Supported commands e 3 Read Holding Registers reading the settings e 4 Read Input Registers reading the readings e 6 Write Single Register changing the settings e 16 Write Multiple registers changing the settings e 17 Report Slave ID checking the device type e 109 Meku Mekuwin configuration software uses this This transmitter uses always even parity 8E1 When the settings are changed by writing a Holding register the settings are changed to the non voltatile EEPROM memory immediately The maximum Modbus frame length is 150 bytes This sets the limit to the number of registers accessed with commands 3 4 and 16 The command 17 will return 0x11 lt byte count gt 0x00 OxFF followed with 6803 V1 0 A123456 for example When the serial connection settings are changed the changes do not affect until the transmitter is 24 powered down This is to prevent breaking the
11. User manual 28 9 2007 V1 1 6803 Thermocouple monitor and transmitter Nokeval INTRODUCTION 6803 is a rail mounted two channel thermocouple measurement unit that is capable to measure the thermocouple resistance in order to rectify its condition The input channels are individual and can be used for different signals The unit has two analog outputs or alternatively one analog and one serial output The serial output accepts Nokeval SCL and Modbus RTU commands Up to four logical alarms can control two alarm relays The inputs are galvanically isolated from the outputs and the supply voltage but not from each other How to use this manual The transmitter consists of several quite independent blocks like the two inputs analog outputs serial communications and so on That is why this manual is also divided in chapters one chapter concerning one block Table of contents There is four built in inter channel functions average difference minimum and maximum More mathematical and conditional operations may be realized with a simple programming language called ELo The front panel has a four digit display and four pushbuttons that can be used to monitor the readings and to change the settings The settings can also be edited on a personal computer using the RS 485 serial connection The ELo program can be edited on a personal computer only not on the front panel First read through the chapter General to f
12. connection while making the changes Data types e BOOL Off on setting O False 1 True in the lower rightmost byte BYTE One byte setting Only the lower rightmost byte of the Modbus register is used e WORD 16 bit setting e ENUM Option list setting The options listed in section Enum tables e CODE Password 12 bits O not used e FLOAT 32 bit floating point number IEEE 754 Least significant word first LSWF little endian e STRINGZ Zero terminated string Within one Modbus register the data is represented the most significant byte first MSBF big endian Registers SPECIFICATIONS Inputs Thermocouples IC rane lin error B 400 1700 C 0 3 C Cc 0 2300 C 0 5 D 0 2300 C 1 E 100 900 C 0 2 G 1000 2300 C 2 J 160 950 C 1 K 150 1370 C 0 5 ETK2 25 800 C L 150 900 C 0 5 N 0 1300 C 0 1 R 0 1700 C 0 5 S 0 1700 C 0 5 T 200 400 C 1 Analog outputs mA output Range 0 20 mA or less Accuracy 0 008 mA Load 0 600 ohm Thermal drift 1 A C Serial communications Connection RS 485 Protocols Nokeval SCL Modbus RTU Baud rates 1200 2400 4800 9600 19200 38400 57600 Bits SCL 8N1 Modbus 8E1 Min response time 3 5 characters Max response time SCL typ 3 max 25 ms Modbus typ 5 max 15 ms Alarms Response Same as meas cycle definable delay Power supply 25 Thermal drift Accuracy 0 02 C C ref 25 C
13. d with too large sensor resistance the alarm activates and the input reading will indicate fault in the display and an alarm associated to that will be always active If an analog output is programmed to follow e g Ini and the resistance alarm activates the output behaves as selected in the output settings Outputs Out1 Break Speed Common Mesurement speed selection Normal speed is intended for normal use and the specifications are valid for that The higher speeds will increase noise The Slow speed can be used when even more accuracy is needed Unit Common Measurement unit with thermocouple C or F Common Speed Unit Conf Differential General Setuptime Display ResInterval Inputs Inputs Recovery Math Common AlmDelay Outputs Int m Alarme n Sensor Relay MaxRes Serial Lopass Pts Mea1 Sca1 Mea2 Sca2 Differential Common Internal grounding of the differential inputs e No The transmitter uses a semiconductor switch to groud the negative line of the channel being measured e Yes The inputs are differential or floating and the potential equalisation must be done externally Setuptime Common When the A D converter is changed to another input channel a small delay is necessary to let the voltages settle This settling time is defined here in
14. e case labeled Free can be taken off and used where needed The RS 485 bus is connected in the connector B Terminal 2 is the internal ground or common Terminal 3 is the more positive line on the idle called D1 and terminal 4 is the more negative line DO All the three lines should be connected 1 1 to the other devices on the bus The actual data lines D1 and DO should use a twisted pair cable 0 5 mm minimum A shielded cable grounded at one point only can be used in a noisy environment If the RS 485 device that acts as a master does not have a common terminal available like Nokeval 711 then the 485 floating jumper should be closed to do the potential equalization using the D1 data line Settings Serial communications settings Note that the Protocol changes here do not affect until the configuration i state is exit Serial protocol e SCL Nokeval SCL protocol e Modbus Modbus RTU protocol Bits 8E1 22 Conf General Display Inputs Serial Math Protocol Outputs Address Alarms Baud Relays Dec Serial Address Serial bus address Valid choices for SCL are 0 123 and for Modbus 1 247 In addition this device PC configuration All the settings of the transmitter can be accessed from a PC A free software Mekuwin is used available at Nokeval WWW site Alternatively with the Modbus protocol the settings can be read and changed u
15. el 50 Level Alarms Alm1 Alm4 Alarm level The alarm will activate when the reading goes past this limit 19 Hyst Alarms Alm1 Alm4 Alarm hysteresis When the alarm has activated the reading must come an amount defined here back from the Level to be deactivated E g if Level 50 and Hyst 5 and Type Hi the alarm will activate at 50 and deactivate at 45 Src1 Src4 Relays Rel1 Rel2 Sources for this relay Select up to four registers that are examined If any of them has a positive value this relay is activated Normally these are one of Alm1 Alm4 registers RA1 RA2 or Off Example If you want this relay to pull when Alarm 1 is activated select Src1 Alm1 and rest of Srcs Off Example2 If you want this relay to pull when either of the resistance alarms activates select Src1 RA1 Src2 RA2 and other Srcs Off Delay Relays Rel1 Rel2 Activation and deactivation delay An alarm must be continuously active for the time specified in Delay in order to cause a real common alarm The delay time is given in seconds The maximum delay time is 3495 seconds NC Relays Rel1 Rel2 Inverting the relay operation Affects only the relay coil but not the LED indicators A1 and A2 No Normal operation normally open the relay pulls when an alarm is active e Yes Inverse operation normally closed the relay releases when an alarm is active ELO PROGRAM Conf General Display
16. figured to follow an input e g In1 register and the sensor is considered faulty the output will behave as selected in Break setting see below Src The register where the output is taken from If you want this output to follow input 1 reading select In1 If you want to follow the difference In1 In2 select Diff etc More about the registers on the page 6 Conf Out1 General Outputs Src Display Out1 Range Inputs Out2 Rdg1 Math Out1 Outputs Rdg2 Alarms Out2 Relays Serial 17 Range Analog output range mA or V The jumpers inside has to be set correspondingly Rdg1 Out1 Rdg2 and Out2 Output scaling Reading Rdg1 corresponds to output signal Out1 in mA or V and Rdg2 to Out2 These have not to be the end points since the transmitter is able to extrapolate Example Reading 0 600 C is wanted to give output of 4 20 mA Settings Range mA Rdg1 0 C Out1 4 mA Rdg2 600 C Out2 20 mA Break Defines how the output acts when the register that this output is programmed to follow indicates fault e Min The output will go to the lowest voltage current it is able to i e 0 V or 0 mA e Out1 The ouput will go to the value in Out1 setting 4 mA in the example above e Out2 Value of Out2 20 mA e Max Maximum voltage current approx 11 5 V or 23 5 mA ALARMS AND RELAYS
17. ges Select AY Save or Undo and push gt There are three possible diagnostic messages Sensor Fault some channel has improper connection overranging or a broken sensor or wires AD Error A D converter is not working Needs service Math Error there is an error in the math program need four registers set the rest to Off After power up the register selected in Src1 is displayed and the rest can be viewed using the AY keys Dec1 Dec4 Display Defines how many digits after the decimal point is displayed on the registers defined in Src1 Src4 Can be set between 2 and 3 Negative values mean that the corresponding number of last digits is rounded to zero Examples with a reading of 12 34 Dec 2 12 34 Dec 1 12 3 Dec 0 12 Dec 1 10 rounded to nearest 10 Ed1 Ed4 Display If register selected in Src is TSro4 I gt a being displayed and the user z pushes the gt key then the A Src2 Ed2 register selected in Ed1 is y gt displayed and its value can be Stes UEes changed Likewise while Src2 is sre gt E04 displayed the register selected in Ed2 can be edited This way the user can change register values manually and affect the ELo program operation or control an analog output manually Other registers than F1 F12 should not be selected in Ed If this operation is not desired set the Ed registers to Off
18. ind out how to mount the transmitter and to open the transmitter case etc and how to get started with the configuration settings either with the front panel or with a PC software Then advance to the chapter Power supply To get the transmitter to measure something read the chapter Inputs To get an analog output read the chapter Analog output and so on Introductio ieia a r a a a a aaa re aaa eaa nea ea raaa aa 2 e A AA S shave E A E E E 3 OELE 0 91 N E EE E A A E E E E E A EE T7 Frontpanelen e a aa aaa a AA a a a aaa a aee adaa aa Eaa 8 WAS cece ct hats need cates danieg ena die oaks tehn tap es Berd aaa te cages ddan retold endl ap a eeseate aad E E A 11 Analog OULDUIS s ccccetyeccsvtiesaveatlocaeedeausssesehintelvavscuddeeving Lede eine AEE E EEEE EE TEENE EEEE 16 Alarms and TOIAYS vac ziccnecsncacecenedseccngtadsedsugdusihs eq ansile egsndsend evaadscene dadadennb dveecandedacdsucdeshlt fecausledagendseedeseseceteneeutes 18 Eege ge alie i A E E cd seat ated cathe decdsdecbidevatecd caved E E E E cauevedee dare 20 Serial COMMUNICATIONS ccceceeeceeeeccee cee eeeeeeeeeeaaaeeeeeeeeesedceeaeaeeeeeeeeeseececcaeeeeeeeeeseseccecceeeeeeeeeeseeseseneeeeeeeees 22 DPESCIPICALONS sonei aa caida laureates Seedvel hota aa a a dayews sedouuads Wehavevtas arenes SA val ieee lea 26 Manufacturer Nokeval Oy Tel 358 3 3424800 Yrittajakatu 12 FIN 37100 Nokia Finland Fax 358 3 3422066 WWW www nokeval com GENE
19. ive in terminal 3 A AOIN 14 1 In2 a Diff amp 2 le LE eae 4 Ig Gnd SW Input gnd_ This switch will pull the input circuitry ground potential to the negative line potential on the channel being measured 11 The potential of the other input can be several volts different than this channel since it is separated by the switches However the switches will not tolerate infinitely voltage The rule is that the both lines and of an input must be within 10 V in respect to the negative line of the other input A difference of more than 30 V may damage the inputs This is the easiest way to connect and the only that will allow several volts between the negative lines of the inputs External linking 1 PA Diff amp 2 gt lt ET 3 gt Link 4 Gnd sw If the input sensors are galvanically isolated from each other then it is recommended to tie them both to the input circuitry ground Connect a piece of wire between the terminals 3 and 4 This ties them to each other too It does not matter if the internal grounding switch is open or closed since the differential amplifier negative input is externally tied to the input ground So the Differential setting in Inputs Common can be in any position Operation Isens arm A Dconverter Senso
20. lue press gt key The gt key can be used to access and change the value of pre selected registers in order to control the ELo program A1 and A2 indicate the states of the alarm relays They are lit if any of the alarms selected for the relay is active The relay NO NC setting does not affect the alarm indicators Most data types are edited simply with AY keys finally exiting with key Floating point values such as scaling and the lopass filter are edited with AVP keys select digit to edit blinking with gt and change it with av When the decimal point is blinking it can be moved with AY The first digit can be replaced with a minus sign A password is set as follows push 4 to select Set means password will be used then push gt to enter the new password Cod 0 is shown The password is a sequence of six keypresses using all the four keys Enter the same password twice if they match Set is shown again and you can exit with If they didn t match Off is shown Redo from start To disable a password push Y to select Off and exit with The math program can not be edited with the front panel An RS 485 connection to a PC is needed Exiting When all settings are done exit from the configuration menu with key Two options are Monitor state Monitoring can be used to examine the internal readings called registers The built in monitoring is started by pressing and Y together Select the item u
21. ocessed according to the sensor type selected For the temperature sensors a temperature reading in C or F is obtained for other input types a mV reading is obtained for example This transmitter provides a possibility for a free two point scaling It can be used to cancel sensor errors or to convert the input signal to the Sensor resistance How it works 15V 1 2 e a 3 4 4 1 In2 Diff amp 2 Ka lt 3 44 ts 4 Gnd sw Input gnd_ The special feature of this transmitter is the ability to measure the thermocouple resistance up to one megaohm The interval how often this measurement is made can be defined in configuration setting Inputs Common Reslnterval When it is time to measure the resistance 6803 uses an analog switch to connect a 10 Mohm pull up resistor to 15V supply pulling the positive sensor line up Moreover another switch is pulling the negative line to the input circuitry ground In this configuration however the A D converter marked as Diff amp in the picture acts as a 850 kohm load The previous millivolt reading obtained with no pull up is used along with other data to calculate the sensor resistance During this measurement the sensor voltage might rise up to one volt The sensor may contain a Settings The configuration menu is divided in several submen
22. r any register The symbol first input there is the input 1 reading gt represents this in the block diagram Registers F1 F12 are controlled by the user The register values can be viewed with a monitor program written in ELo language function either on the front panel or the PC Any register can be used as a source for another configuration program Mekuwin block For example the analog output 1 can be set Register Name 1 Int 2 In2 3 Res1 4 Res2 5 Avg 6 Min 7 Max 8 Diff 9 RA1 10 RA2 11 CJ 12 Cycle 13 Out1 14 Out2 15 Alm1 16 Alm2 17 Alm3 18 Alm4 19 Rel1 20 Rel2 21 F1 22 F2 23 F3 24 F4 25 F5 26 F6 27 F7 28 F8 29 F9 30 F10 31 F11 32 F12 33 Keys Keys register Explanation Input 1 scaled reading C F mV Input 2 scaled reading Input 1 resistance kohm Input 2 resistance Average of the readings In1 In2 2 Smaller of the readings In1 In2 Greater of the readings Difference In1 In2 Resistance alarm 1 state O passive 1 active Resistance alarm 2 state Internal cold junction temperature in C The measured time to get all the channels in seconds Analog output 1 signal in mA or V Analog output 2 signal in mA or V Logical alarm 1 state O passive 1 active Logical alarm 2 state O passive 1 active Logical alarm 3 state O passive 1 active Logical alarm 4 state O passive 1 active Relay 1 state O passive 1 active Relay 2 state O passive 1 active Free floating poin
23. rprocessing This connection method will give the best performance against disturbances and overvoltages Other external path F Diff amp AJOIN gt Gnd sw The potential equalization does not have to be a link on the terminals it can be a longer path as far as it keeps the potential between terminals 3 and 4 small enough If an external path exists then it is best to open the internal grounding switch by setting the Differential setting to On in the Inputs Common menu An example of this could be two thermocouples mounted on the same metal object In this case the negative wires are not allowed to be connected together at the transmitter terminals The link between terminals 3 and 4 can not be used Instead have the link on the other input only it will keep the differential amplifier inputs near ground on both inputs Scaling Lowpassfilter J we In1 In2 ae Built infunctions Avg In Min Max Diff Several analogue switches are used to connect the A D converter and the sensor current supplies to the channel being measured In addition to the two external channels there is two internal channels 12 gt the cold junction temperature for thermocouples and the RTD excitation current measurement The result is pr
24. seconds If the sensor has low resistance and capacitance 0 02 seconds is sufficient If the reading flickers all the time try increasing this time ResInterval Common This setting defines how often the sensor resistance is measured Selectable 0 200 e 0 Not at all All the resistance functions are disabled e 1 Every measurement is resistance measurement normal readings are not obtained e 2 Every other is resistance measurement e 10 Nine normal measurements and one resistance measurement 14 Recovery Common After the sensor has been stressed by the resistance measurement it needs some time to discharge Recovery setting defines the time in seconds If you notice the reading to deflect now and then after the resistance measurement increase this setting until the phenomenon disappears Note that a sensor with more resistance will need more recovery time so this should be predicted AlmDelay Common When the sensor resistance exceeds the MaxRes value defined in Inputs InX MaxRes the resistance alarm is not given unless the situation stays for long enough This setting ddefines how many resistance measurement cycles must give a resistance above the MaxRes in order to the alarm to activate The same applies to the alarm deactivation Set to 0 if no delay is desired Sensor In1 In2 Input range and sensor selection Off Channel not used 55mV 100mV 1000mV 2500mvV Voltage inpu
25. sing AY keys and finally exit with The registers are explained on the page 6 The last item is Diag that can be used to see diagnostic messages Push gt If nothing happens then there are no messages If happens try AY to see if there are several messages Exit with Settings General In ig fi Conf configuration CiCode settings menu General Display there is two Display submenus Inputs Src1 concerning the Math Dec1 front panel Ed1 General and Outputs Display Alarms Relays i Serial Src4 Dec4 Ed4 CfCode General This defines a password for the settings If this is set the settings can t be accessed without knowing the password To change the password on the front panel go to the CfCode setting and push gt to edit the value Options Off and Set are shown select Set with the AY keys Then push P and Cod 0 should be displayed Now enter six keypresses using any of the four keys Then enter the same sequence another time If they matched Set is displayed again and you can exit with Otherwise Off is displayed Src1 Src4 Display Display submenu is used to define what readings or registers you want to see on the display Up to four registers can be selected in Src1 Src4 registers are described on page 6 If you do not shown Save to keep the settings made and Undo to discard all chan
26. sing the standard functions SCL protocol A more detailed description of the Nokeval SCL protocol can be downloaded from Nokeval WWW site This unit understands the following SCL commands TYPE Returns the model name and software version 6803 V1 1 without the quotation marks SN Returns the serial number e g A123456 MEA CH 1 Returns the scaled reading of input 1 All the registers can be read this way The response consists of characters 0123456789 The scientific notation e g 1E3 is not used In case of invalid 23 will always answer at address 126 when SCL protocol is used Modbus will accept General call address 0 but not respond to it Baud Baud rate selection Options 1200 2400 4800 9600 19200 38400 and 57600 bits per second Dec The input readings and other registers can be read as 16 bit integers at Modbus Input registers starting at 1000 This setting defines how many digits is after the decimal point E g Dec 2 reading 3 1415 is given 314 as an integer Of course an RS 485 connection to the PC is needed for example Nokeval DCS770 USB RS 485 converter Connect the transmitter to the PC start Mekuwin and make sure both ends have the same serial parameters the protocol the baud rate and the address Mekuwin Slot parameter should be 0 reading e g sensor break the response consists of dashes With over underflow the response is 4444 or uuUU
27. st src1 src2 Exclusive OR Sums src and dest and places the result in dest Exactly same as writing dest desttsrc destX src The same for other operators e g 18 10 dest src Jumps and conditional jumps Jumps given number of lines forward or backward E g 2 will execute the Lines command that is two lines above this line 2 will skip the next line x y lines Jumps given number of lines if x equals y E g 15 0 3 x y lines Jumps if x is not equal to y x lt y lines Jumps if x is less than y x lt y lines Jumps if x is less or equal to y x gt y lines Jumps if x is greater or equal to y x gt y lines Jumps if x is greater than y References decimal constant allowed characters plus minus point digits 0 9 1 register 1 1 register defined by register 1 contents 1 21 SERIAL COMMUNICATIONS Connections and jumpers cS T E aL E l oT O AAO r 4 3 2 1 4 3 2 1 A B Hl Free 682 1 Out2 mA Out2 V F Out2 485 234 Don t use G H ace floating term 1121314 1121314 Ered Free The RS 485 serial communications is alternative to The 485 term jumper should be closed if this is the second analog output they can t be used at the last device on the bus It enables an AC the same time The selection between them is termination 1 nF 110 ohms The jumpers made by jumpers inside th
28. t register for ELo programs Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Free floating point register Front panel key state see below Keys register gives a sum of the codes of the keys currently pressed Key Code A 2 v 4 8 gt 16 POWER SUPPLY The transmitter 6803 is available for two supply voltage ranges that are nominally called 24VDC and 230VAC 6803 24VDC This model accepts supply voltage of 20 to 28 V DC or AC The supply is connected in connector A terminals 1 and 2 Either polarity will do This transmitter will consume less than 200 mA However at power up it will need 500 mA gt NO aaa 4 3 2 1 A B 6821 F 112 314 G H 1121314 112 314 6803 230VAC This model accepts supply voltage of 85 to 260 V DC or AC The supply is connected in connector A terminals 1 and 3 This unit has an internal pre fuse If an external one is used it should be at least 500 mA T gt aS AN oO IZKA 4 3 2 1 A B 6821 F 1 2 3 4 G H 1 2 3 4 1 2 3 4 FRONT PA
29. term N 9 Free O Free Configuration settings There is a plenty of settings that are used to On the front panel see chapter Front panel define the operation of the inputs the outputs etc page 8 There is two ways to access them Using a PC and a serial communications see chapter Serial communications section PC configuration page 22 Registers Analog input x2 writes into a register Resistance gt can be configured to read any register Reading Lowpassfilter Display Registers Scaling ae oe 123 4 Nd aa Res1 Res2 Built infunctions d Analog output x2 Avg Avg L f Min gt Min R Max gt Max Diff ng Dif U name Serial interface 18 1 Ga 072 gt gt F12 Alarm comparator x4 OE een Relay output x2 Al indicator The function blocks of this transmitter inputs outputs etc are quite independent from each other The information between them is delivered in so called registers The registers can be seen in the block diagram on the gray background Most of the registers are controlled by some function block For example the register In1 is controlled by the to read the register In1 o
30. truth values e g the states of the alarms The program can t be entered nor edited on the front panel an RS 485 connection and a PC is needed The maximum length is 160 characters the line feed consuming one character In the language the registers are referenced by using their code e g the register F1 is accessed with an expression 18 The register 0 is a special register every time the user program is executed it tells the time in seconds from the previous execution This can be used while generating timings or integrating or derivating a reading See the examples The program is executed every time the A D converter gets a new reading for any channel The program run time is limited to 200 operations or lines to avoid jamming the whole transmitter due to an erratic program If the transmitter detects any errors in the program the Math error diagnostic message will be active it can be examined in the built in or Mekuwin Monitor mode program The program is entered in the configuration settings Math submenu Copies a value from src to dest E g 18 3 14 will place a value 3 14 in register 18 Sums src1 and src2 value and places the result in dest register E g 11 1 10 will add register 1 contents to value 10 and place the result in register 11 Calculates a square root E g 18 1SQ Bitwise AND If applied to a floating point value it is first converted to a 8 bit integer dest src1 src2 Bitwise OR de
31. ts Can measure also negative voltage The reading is in millivolts e TcB TcT Thermocouples The result is in Celsius or Fahrenheits according to the Unit setting MaxRes In1 In2 Maximum acceptable sensor resistance in kilo ohms If the sensor resistance is higher than this the resistance alarm is activated after a definable delay and the reading indicates sensor fault Dashes are displayed Lopass In1 In2 First order lowpass filter for the reading Attenuates noise and disturbances Set time constant to 63 of step change in seconds or 0 to disable Pts In1 In2 Number of scaling points The scaling means converting the reading to represent some other engineering reading The scaled value is used on the display serial output analog outputs and alarms e 0 No scaling e 1 One point offset correction The reading corresponding to Mea is scaled to be Scat when displayed using appropriate offset value e 2 Two point scaling Readings from Mea to Meaz2 are scaled to be Sca1 to Sca2 Any values can be used these have not to be the end points Mea1 Sca1 Mea2 and Scaz2 In1 In2 Scaling points Visibility of these settings depends on the Pts setting Unscaled reading Mea is converted to Sca1 and Mea2 to Scaz2 15 These scaling points can be conveniently used to calibrate a sensor transmitter pair in a thermal bath First set the scaling off by setting Pts 0 Apply one
32. us The input settings are in a submenu called Inputs which is further divided in Common In1 and In2 submenus In1 and In2 submenus are identical 13 engineering units A first order lowpass filter can be applied to remove noise and disturbances This transmitter calculates always four inter channel readings the average the smaller the greater and the difference of the inputs capacitance of dozens of nanofarads so some actions are needed before a normal measurement can be taken First 6803 short circuits the sensor using approx 2 kilo ohms for 20 milliseconds to remove the charge Secondly when the next normal measurement is taken the sensor is connected to the A D converter using the analog switches and then a longer than normal recovery time is waited before starting the A D conversion This time is user selectable see Inputs Common Recovery The measured resistance is available in registers Res1 and Res2 for ELo program alarms display or serial reading Resistance alarms The input channels have individually programmable alarm levels for their sensor resistance MaxRes When the sensor resistance exceeds this value sensor resistance alarm RA1 or RAZ is activated The registers RA1 and RA2 can be used to control a relay see e g Relays Rel1 Src1 In order to avoid false alarms the resistance alarms have a programmable activation deactivation delay in Inputs Common AlmDelay When the delay has elapse
Download Pdf Manuals
Related Search