How can you troubleshoot discrepancies between sensor measurements and values displayed via analog outputs on the sc200/sc1000 controllers?

Document ID

Document ID TE2461

Published Date

Published Date 27/05/2017
Question
How can you troubleshoot discrepancies between sensor measurements and values displayed via analog outputs on the sc200/sc1000 controllers?
Summary
sc100/sc200 discrepancies in measuremnts displayed vs analog outputs
Answer
   Follow the steps below to resolve discrepancies.

1.Define components.  Draw a picture, if necessary, and cover basic troubleshooting questions:
   When did this problem first begin?
   When was it last working correctly?
   How long has the instrument been in operation?
   What happened before this began (maintenance, plumbing changes, and electrical issues like power surge, lightning strike, power outage or any other changes)?
   What troubleshooting tactics have already been tried?
   What is the serial number?

2. Document the sensor measurement values shown on the controller and SCADA.

3. Check output configuration and scaling on controller:
    Menu> System Setup> Output Setup> Output #1 or #2>
    Confirm Source, Parameter, Function and Filter
   
    Confirm scaling settings
    Activation> Set Low Value/ Set High Value
    Double-check the value displayed for measurement reading matches the correct mA output on the controller’s home page display
 
    Bottom of home page on sc100/200 will display mA value for Output 1 or Output 2 by scrolling with up and down arrows
    Use this equation: mA=[(measured value/scale)*16]+4
    For example, calculate the mA output for a turbidity sensor that is scaled from 0 to 10 and currently reading a value of 1.0.  mA=[(1/10)*16]+4, or 5.6 mA.
    
    Check scaling on SCADA :
    Use OUTPUT CAL to push 4 mA and 20 mA signals to the SCADA to confirm SCADA scaling. (Menu> Test/Maint> Output CAL)
    While using Output Cal, check values displayed on controller.  Customers have been known to change these values prior to calling, for example, they may have set them to 4, 20, or their desired
    high and low scaling values.
                     
                        For sc100:
1. Output Cal 4mA default is approximately +55000
2. Output Cal 20mA default is approximately +13000

                         For sc200:
1. Output Cal 4mA default is approximately +10500
2. Output Cal 20mA default is approximately +52600 to +65500