Posted 23 Aug 2016 Dear All I'm facing a problem with Allen Bradley PLC System. We are using a redundant I/O and redundant controller configuration of Allen Bradley ControlLogix 5000 series. In one of the AI card, on channel 0, following configuration is made: Input type: 0 to 5V High Range: 5V High EU: 20,000 Low Range: 1V Low EU: 4000 There is a gas detector connected to this channel which is supplying 4-20mA. What I observe is that when we simulate this channel using our mA calibrator, the raw counts does not increase more than 10,000. Why it is happening? Why the raw counts are not going upto 20,000 as configured in the channel configuration. Any help will be appreciated. Share this post Link to post Share on other sites
Posted 24 Aug 2016 (edited) 13 hours ago, SB said: Dear All I'm facing a problem with Allen Bradley PLC System. We are using a redundant I/O and redundant controller configuration of Allen Bradley ControlLogix 5000 series. In one of the AI card, on channel 0, following configuration is made: Input type: 0 to 5V High Range: 5V High EU: 20,000 Low Range: 1V Low EU: 4000 There is a gas detector connected to this channel which is supplying 4-20mA. What I observe is that when we simulate this channel using our mA calibrator, the raw counts does not increase more than 10,000. Why it is happening? Why the raw counts are not going upto 20,000 as configured in the channel configuration. Any help will be appreciated. Why is the input range set to 0-5V if you are connecting a 4-20mA input to it? The CLX PLC is not a SLC. You aren't stuck with using archaic card scaling methods. Try this: Input Range: 0 mA to 20mA Low Signal: 4mA Low EU: 0.0 High Range: 20mA High EU: 100.0 If it's a gas detector then it's output is scaled to %LEL. The High EU value needs to be the maximum %LEL of the detector Edited 24 Aug 2016 by Michael Lloyd Share this post Link to post Share on other sites
