gould

Micrologix 1100 Write to Modbus compressor

5 posts in this topic

Hey guys, I'm using a micrologix 1100 to communicate through Modbus to a Ingersoll rand Air Compressor (controller is a xe-145m) and air compressor is a R110i. I have multiple read and writes going to and from the compressor already so I know my communication is good. I'll link the Modbus addresses...heres my set up 

Trying to write host/local stop/start load/unload commands to my compressor but I keep getting Modbus error code 3 on my message. 

Modbus command: 16 write multiple registers (4xxxxx) (tried single aswell)

Size in elements: 1

slave node: 1

Modbuss Adress: 40001 

on the modbuss table 40001 should be status/control read/write , it doesn't give me a range but refers to figure 1 and says bit 0 is my local/host command bit 1 is my stop/start...

So when I try to use bit 0 and send a '0' into the write message it gives me the error code above.. I also tried a 1, still thing, could anyone take a look at this table for me and figure out what im doing wrong id appreciate it greatly, thanks.... 

https://www.ccontrols.com/support/dp/XeMModbusRegisters.pdf

Edited by gould

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Curious minds want to know what the problem was.

I made the attached PDF to let my SCADA group know what the problem ended up being with a MODBUS ASCII problem (why... why is MODBUS ASCII even necessary in 2021?). 

SLC PLC talking to a Fisher ROC. "Nothing had changed in either program", "I only looked at it, I didn't change anything". The clue came from decoding the Function Code returned. 131. It's not easy to see 131h in the attached PDF because of the ASCII protocol.  Page 2,3, and 4 are the useful bits in the attachment. The rest of it was from my spreadsheet. I guess attachments aren't allowed anymore so I'll go with a dropbox link instead

https://www.dropbox.com/s/e9usj5u7qmq5m0m/MODBUS%20ASCII%20and%20RTU%20Decode.pdf?dl=0

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Thanks Michael! Never thought of using colors to explain it,

Hope your warm and cozy with lights and water.

Edited by a062549
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13 hours ago, a062549 said:

Thanks Michael! Never thought of using colors to explain it,

Hope your warm and cozy with lights and water.

I had to do something the align the neurons. LOL

I'm up in NW NM. Ironically I've had a better quality of life here than my kids down in TX. NM does winter pretty well and in this part of NM it's not that harsh

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