Emerson Exchange 365

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simulation with a device control block attached to field IO

At times we need to shut a pump down and work on it and not have anything else that is interlocked with the pump shutdown.   Normally we bypass the conditions  in other modules that look at the pump's status.  Every once in a while we get into a situation where that is not the best solution.   In those conditions we have tried enabling simulate.  However once we turn on simulate the digital out that writes to the  field IO remains energized.   It remains energized even if we change the SP of the DC block to STOP.   

The DC block SP is  stopped but the field IO is energized.  The result is the motor starts whenever power is reapplied to the pump motor.   A 500 HP motor starting without expecting it is not a good thing.  

Is there some way to simulate the status of of DC block to running but also be able to turn the field IO off?  

We are version 11.3 1  

doug bray

• 2 Jun 2021 8:27 PM
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2 Replies

• Benji_Kidmose

  

  • 2 Jun 2021 9:44 PM

  Is your IO assigned to the DC Block? break it out into DI/DO then you can do what ever you want to the DI, wire you DI run status direct to the DC block. use the DI output or a parameter connected to the DI called RS in your downstream modules when referencing Run Status state. Then you can simulate the DI to have downstream modules that reference the point without the DC block setting its outputs to ON. Same thing with having the MTR SD and CTL as DO, you can force these off to ensure the bucket relays are not energized. Get rid of IO assigned direct controls blocks, ties yours hands

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• doug bray

  

  • 3 Jun 2021 1:19 PM

  In reply to Benji_Kidmose:

  Thanks for the reply. We have a couple of thousand motors and they do not have DI and DO blocks. The IO is assigned in the DC block.

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