Experimental Physics and
Industrial Control System

Philippe Laurent <[email protected]> · Tue, 2 Feb 2016 14:38:18 +0000

Hi Mark,

I get the same bahaviour with my waveform SCAN at 1 second.

I believe I see an error in the readInt32Array fonction of drvModbusAsyn.c when you increment i to read data from the memory buffer. You always increment by 1.

Best regards.
Laurent.

________________________________________
De : Mark Rivers [[email protected]]
Envoyé : mardi 2 février 2016 15:26
À : Philippe Laurent; [email protected]
Objet : RE: Modbus 2.5 How to read a INT32_BE array from a modbus function

Hi Philippe,

I looked at the code and I believe I see the error.  In fact I think the error occurs in 2 places.  One is for I/O Intr scanned records (like you are using) and the other is for periodically scanned records.  Can you change your database temporarily so that the waveform record is periodically scanned and see if you get the same problem?  If so I will fix the driver and have you test.

Thanks,
Mark

________________________________
From: [email protected] [[email protected]] on behalf of Philippe Laurent [[email protected]]
Sent: Tuesday, February 02, 2016 2:37 AM
To: [email protected]
Subject: Modbus 2.5 How to read a INT32_BE array from a modbus function

Hello,

I try to read a INT32_BE array from a modbus function into a Waveform using dtyp = asynInt32Array.

I get a array of long in the waveform, but the data are not correctly read from modbus.

It looks like, the driver constitutes a long with :

modbus index 0 + modbus index 1-> waveform data[0]
modbus index 1 + modbus index 2-> waveform data[1]
modbus index 2 + modbus index 3-> waveform data[2]
...
Instead of :

modbus index 0 + modbus index 1-> waveform data[0]
modbus index 2 + modbus index 3-> waveform data[2]
modbus index 3 + modbus index 4-> waveform data[3]

My record is :

record(waveform, $(EQPT):PostMortemRaw2) {
  field(DTYP, "asynInt32ArrayIn")
  field(DESC, "input modbus data")
  field(NELM, "50")
  field(FTVL, "LONG")
  field(SCAN, "I/O Intr")
  field(INP,  "@asyn($(EQPT):PostMortemRd2 0)INT32_BE")
}

My modbus function is :

drvAsynIPPortConfigure("LBEC-DCCT31","172.16.60.231:502",0,0,1)
modbusInterposeConfig("LBEC-DCCT31",0,300,2)
drvModbusAsynConfigure("LBEC-DCCT31:PostMortemRd2","LBEC-DCCT31",1,3,228,100,6,2000,"PLC")

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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System