Modbus to DeltaV

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Thread Starter

hnmcnabb

I am getting Device failure error intermittently on DeltaV ver 12 when trying to communicate with atlas compressors using MK5 (atlas compressor to gateway to convert CAM to Modbus RS485). We are using a serial card (s-series) and all the data seems to be mapped correctly. I can see the data on ModScan at the gateway (changing and looks good) and also plug in at the serial card and the values are good and changing. In diagnostics I am seeing the values coming in, but there is a device failure that keeps coming in and out. Anyone have any ideas?
 
Hi,

Are you getting the failure codes (Modbus exception codes?) in Modscan? If so what are they?

How many compressors (Modbus Slaves) are they?

Termination resistors? How is the cabling? and check the connectors.

/Patrick L
 
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Heather mcnabb

I am not getting any failure codes in the in the Modscan, and it is only one compressor. (1 Slave). We have put 120 ohm terminating resistors on each end and checked all connectors which seem good. Even on the deltaV end of right before we terminate at the card we see good data in modscan. We plug it into the system and we get the intermittent device failure.
 
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