SG1000C Operation Manual
Contents
1. s proper mounting locations electrical connections calibration procedure troubleshooting hints and product specifications all still generally apply and should be followed as closely as possible for successful SG1000C operation However for other applications different mounting hardware may be needed than shown Because of numerous variances if other mounting hardware is needed the user must fabricate or acquire it on their own Physical Appearance and Installation Overview Figure 1 is the front view of the SG1000C showing the encoder output shaft Cable Encoder Shaft 3 8 16 UNC 2A threads Figure 1 6111 Blue Circle Drive Minnetonka MN 55343 Phone 952 930 0100 Fax 952 930 0130 ISO 9001 2000 Certified ELECTRO SENSORS Superior e Systems e Solutions The SG1000C attaches to the process s single turn shaft using an end of shaft mounting method See Figure 2 The SG1000C s encoder shaft end screws into a single 3 8 inch diameter hole to a depth of 0 625 inch having 3 8 16 UNC 2B threads Even though the SG1000C is mounted to the process shaft via the end of shaft mounting method installation of flexible conduit and of the optional stabilizer bracket is recommended which allows the SG1000C to float along with any wobble of the process s shaft while still preventing the SG1000C from rotating along with that shaft see Fig 2 Note The stabilizer bracket s U bolt is sli2. G1000C Single Turn Position Monitor SG1000C general description The SG1000C is a rugged medium cost encoder based position sensor with a 4 20 mA output The SG1000C is used to accurately measure or sense the position of a process or operation that has a repetitive single turn rotary movement sensing a rotary position anywhere from 0 to 360 The SG1000C was developed for use as a Grain Distributor Position Monitor sensing the position of the distributor s chute However the SG1000C can also be used in other applications where a single turn position needs to be monitored The SG1000C has two modes calibration mode and normal operating mode A simple calibration procedure teaches programs the SG1000C the encoder value corresponding to the home 0 position Once programmed the SG1000C outputs e A4mA DC signal when the encoder is at the 0 home position a k a the 0 position A 20 mA DC signal when the encoder is at the 359 full single turn position a k a the 100 position Note The full turn position is at 359 and not 360 since 360 is a complete wrap around resulting in 0 again Any mid span encoder position between 0 and 359 is represented by the output signal being proportionally between 4 and 20 mA Note Since the SG1000C was developed for use as a Grain Distributor Position Monitor this user manual is written mainly for that application For other single turn applications the SG1000C
3. a depth of 0 625 inch and 3 8 16 UNC threads Cylindrical aluminum housing cover Outside diameter of 3 11 16 inch Maximum length of 7 5 8 inch length includes cover and encoder shaft The stabilizer bracket can be semi rigidly mounted to the application s framework using two user supplied 5 16 diameter bolts Environmental considerations c UL LISTED e NEMA4X Cast Aluminum Housing e Temperature range of 40 C to 65 C 40 F to 149 F e Humidity range of 0 to 90 non condensing Class I Div 1 Groups C D US Class II Div 1 Groups E F G UL File E249019 C Operator interface e One pushbutton enter calibration mode upon power up calibrate for 0 home position e One slide switch select calibration direction CW CCW Operation modes e Normal Operating Mode output 4 mA to 20 mA signal corresponding to shaft position e Calibration Mode select calibration direction calibrate for 0 home shaft position T O requirements Input External power supply of 24 Vdc 10 The SG1000C s current draw is 40 mA DC or less Output 12 mA DC output signal for an un calibrated system when running in Calibration Mode or in Normal Operating Mode with improper calibration Output 4 mA DC to 20 mA DC output signal proportional to shaft position for a properly calibrated system running in Normal Operating Mode Additional Information To get additional information about the SG
4. mA For an invalid calibration The output signal remains at 12 mA See the Valid Calibration and Invalid Calibration sections below for details regarding whether or not your SG1000C accepted the process s calibration position 6 Replace the back end cover onto the SG1000C This ends the calibration procedure Valid Calibration Normal Operating Behavior Assuming the user followed the calibration process correctly the SG1000C behaves as follows When the shaft is at the 0 home position i e the 0 position the output signal is 4 mA When the shaft is at the 359 full turn position i e the 100 position the output signal is 20 mA Any mid span position between 0 and 359 is represented by the output signal being proportionally between 4 and 20 mA 1 e proportionally between 0 and 100 Note Since the SG1000C is designed to monitor one full single turn of shaft rotation theoretically this results in no 0 or 100 run out zones left over on either end of the rotary sweep i e once the 359 full turn position is reached any further movement results in an immediate rollover to the 0 home position However to make the the hardware calibration of the R7 and R8 potentiometers easier there is a two encoder count plateau at the 0 home position and a two encoder count plateau at the 359 full turn position This means the SG1000C signals 4 mA for both the 0 home position as well as for o
5. 1000C visit our website at www electro sensors com Notice Copyright 2009 Electro Sensors Inc All rights reserved No part of this document can be duplicated or distributed without the express written permission of Electro Sensors Inc While the information in this manual has been carefully reviewed for accuracy Electro Sensors Inc assumes no liability for any errors or omissions in the information Electro Sensors Inc reserves the right to make changes without further notice to any part of this manual or product described in this manual Free Catalog and Application Assistance 1 800 328 6170 Website www electro sensors com 990 002420 Revision D
6. Note The SG1000C s 0 home calibration position should be located in the space between any two downspouts of the Grain Distributor system and NOT pointed at any particular downspout since this home position also ends up being the 20 mA to 4 mA rollover point e Ifthe 20 mA to 4 mA rollover point occurs while pointing at a downspout then it could cause confusion during normal operation if the chute positioning was off by just one encoder count That could cause the SG1000C to indicate the chute as being at the 4 mA position when in reality it was still at the 20 mA position the difference being only one encoder count Hence it is best to locate the 0 home position at a spot that is less critical to the 20 mA to 4 mA rollover point i e such as between downspouts 5 Press the calibration switch SW2 e This captures the present encoder count This value is then used for the 0 home position e The SG1000C then automatically exits the calibration mode and enters the normal operating mode Note The calibration mode is exited at this point for both valid and invalid calibrations For a valid calibration If the user does not Free Catalog and Application Assistance 1 800 328 6170 Website www electro sensors com 990 002420 Revision D immediately turn the shaft then the output signal is 4 mA Because the shaft was left in the 0 home position from step 5 the output signal is at 0 which is 4
7. alibration mode then you have properly restored R7 and R8 settings Continue and complete the calibration procedure for the shaft s 0 home position D YS How to clear out the existing calibration and reprogram the SG1000C First remove 24Vdc power then press and hold in the SW2 button while re applying the 24Vdc power to the SG1000C Continue to keep the SW2 button pressed in for a few seconds until the SG1000C outputs 12 mA then release the SW2 button The old calibration has now been cleared out and the SG1000C is in calibration mode awaiting new calibration See the Calibration Procedure section for complete details Specifications Performance The SG1000C s built in 9 bit absolute encoder measures shaft position internal readings are 0 up to 511 counts The SG1000C uses a 1 1 gear ratio between the output shaft and the encoder The SG1000C s 4 20 mA output signal resolution is 0 2 and is updated once every 7 msec 0 2 is 1 encoder count out of 512 counts Since the 4 20 mA output spans 16 mA a 0 2 resolution gives an incremental change of 0 032 mA 16mA x 0 002 The SG1000C s maximum mechanical rated speed is 200 RPM In the event of power failure or shutdown the EEPROM retains the shaft calibration direction CW CCW and shaft calibration positions 0 home 359 full turn ELECTRO SENSORS Mechanical packaging e Mounts on end of shaft via single 3 8 inch diameter hole to
8. fined via the viewer looking at the back cover end of the ELECTRO SENSORS enclosure and not the encoder shaft end of the enclosure e Ifthe encoder shaft turns in the CW direction as the process s shaft is turned from the 0 home to the 359 full turn position then set SW1 to the OFF position i e toward the center of the PC board See Figure 4 e If the encoder shaft turns in the CCW direction as the process s shaft is turned from the 0 home to the 359 full turn position then set SW1 to the ON position i e toward the edge of the PC board See Figure 4 Note The direction switch SW1 is monitored only briefly during a calibration power up i e calibration switch SW pressed in while applying 24 Vdc to the unit After the unit powers up and is in calibration mode SW1 is no longer relevant Hence changing SWI at this point has no effect Because of this SW1 must be set to the desired position before the 24 Vdc power is applied to the unit in order for the calibration power up to capture the desired setting of SW1 3 Press in the calibration switch SW2 then a power to the SG1000C Do not press SW2 multiple times or allow it to change state just keep it pressed in Continue to keep SW2 pressed in for a few seconds until the SG1000C outputs a constant 12 mA from its signal line then release the button The SG1000C is now in the calibration mode ly 24 Vde 4 Move the SG1000C to the 0 home position
9. ghtly oversized to provide about 1 8 of slack between it and the SG1000C The U bolt s slack prevents it from rigidly clamping to the SG1000C s conduit port Flexible Structural Framework conduit Figure 2 Electrical connections The SG1000C s electrical cable has three wires plus a shield wire Connect as follows See Figure 3 24Vdc Power Supply PLC Etc 250 to 500 ohm load Vv Figure 3 e Connect the shield wire to the earth ground e Connect the black wire to the power supply terminal e Connect the red wire to the power supply 24 Vdc terminal e Connect the clear wire to a resistive load of 250 Q to 500 Q usually this load is internal to a PLC etc Free Catalog and Application Assistance 1 800 328 6170 Visit Us Online www electro sensors com 990 002420 Revision D Note The clear wire is the 4 20 mA DC output line The other side of the 250 Q to 500 Q load must be connected to the power supply terminal e See Figure 4 below for related information Calibration Procedure Calibration consists of teaching the SG1000C the encoder value for the 0 home position Note After being taught the encoder value for the 0 home position the SG1000C then automatically figures the encoder value for the 359 full single turn position as per the CW CCW direction set by Var01 The six calibration steps are as follows once the user is fa
10. miliar with the calibration procedure they need only follow the underlined portions as a quick calibration guide 1 Remove twist CC SG1000C This provides access to the edge of the SG1000C s printed circuit board namely the direction switch SW1 the slide switch and the calibration switch SW2 the push button switch See Figure 4 for locations of these switches ew Nnu the back end cover from the wi CWIOFF l E Jeon SW1 Detail TB1 Clear Black Shield Figure 4 Note Also on the edge of the PC board are two adjustment potentiometers R7 and R8 and a 3 pin terminal TB1 Pot R7 is for tweaking the 4 mA output level Pot R8 is for tweaking the 20 mA output level These two pots are factory adjusted and the user normally should not have to adjust them It is best to leave these two pots alone The user normally should not have to disconnect the 3 wire cable from the SG1000C But if they do so they must reconnect the 3 wire cable to the SG1000C as follows e 24Vdc red wire to TBI 1 e 4 20mA signal clear wire to TB1 2 e Power supply ground black wire to TB1 3 2 Before applying 24 Vdc power to the SG1000C set the direction switch SW1 on the SG1000C s PC board to the proper position for the application SWI tells the SG1000C the direction the encoder turns CW or CCW as the process s shaft is turned from the 0 home to the 359 full turn position The CW or CCW direction is de
11. n mode When R7 and R8 are at their factory settings the output signal is 12 mA during calibration mode Recall that the output signal remains at 12 mA until the calibration process is completed If during calibration mode the output signal is not 12 mA then most likely the R7 and R8 factory settings have been tampered with Free Catalog and Application Assistance 1 800 328 6170 Website www electro sensors com 990 002420 Revision D Troubleshooting Hints cont If you feel confident that you have followed the calibration procedure properly perhaps have done it several times over and followed the troubleshooting hints in 1A 1B 1C and 1D AND you still see strange values other than 4 mA at 0 home and 20 mA at the 359 full turn then you can attempt to restore R7 and R8 to the factory settings by doing the following This assumes you have already calibrated your SG1000C for the 0 home position A During normal operating mode move the shaft to your 0 home position Adjust R7 until 4 mA is output from the signal line B During normal operating mode move the shaft to the 359 full turn position Adjust R8 until 20 mA is output from the signal line C You can now test and verify that your R7 and R8 are indeed set back to factory settings Do this by re entering the calibration procedure press in SW2 then apply power Ifthe 4 mA to 20 mA output signal is at 12 mA or fairly close when in the c
12. ne encoder count after the 0 home position the SG1000C signals 20 mA for both the 359 full turn position as well as one encoder count before the 359 full turn position e Fora properly calibrated SG1000C the direction of calibration CW or CCW and the encoder values for the 0 home and 359 full turn shaft positions are all stored in the SG1000C s EEPROM memory Note Since a properly calibrated SG1000C can never enter the calibration mode again by itself after the calibration mode is exited the direction switch SW1 and the calibration switch SW2 are ignored during normal operating mode This means that for a properly calibrated SG1000C the calibration results are protected from the user inadvertently changing the SW1 position or by pressing SW2 during normal operating mode ELECTRO SENSORS 3 4 If re calibration is needed see the section below titled How to clear out the existing calibration and reprogram the SG1000C Invalid Calibration Error condition behavior Assuming the user followed the calibration process incorrectly the SG1000C behaves as follows e The output signal remains at a constant 12 mA after the calibration mode is automatically exited Power ups calibration vs normal operating mode An SG1000C that is un calibrated or if the calibration attempt was invalid automatically powers up in the calibration mode the next time power is applied A properly calibrated SG1000C powers
13. up in the normal operating mode when power is applied Troubleshooting Hints As an aid to troubleshooting see figure 3 on how to connect an ammeter to directly measure the 4 20mA output signal 1 If your SG1000C outputs a 4 mA to 20 mA signal but not at the shaft positions expected then double check the following A Before you performed the calibration procedure did you set the direction switch SW 1 to the proper position CW or CCW before applying power to the SG1000C Did you program the SG1000C at your desired 0 home position Is your SG1000C terminal TB1 wiring correct e 24Vdc red wire is TB1 1 e 4 20mA signal clear wire is TB1 2 e Power supply ground black wire is TB1 3 Assuming conditions A B and C are proper and your SG1000C still seems to behave improperly then try re calibrating again paying close attention to the six calibration steps B C D 2 Ifyou have gone through troubleshooting hints 1A 1B 1C and 1D and if your SG1000C seems to otherwise respond properly from 0 to 359 of rotation with the only exception being that strange values other than 4 mA and 20 mA are output for the positions e g 3 mA at 0 home position and 23 mA at the 359 full turn position then possibly the R7 and R8 factory potentiometer settings have been tampered with See Figure 4 for location of these pots Evidence of R7 and R8 tampering is most easily seen when in the calibratio
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