Device error: [02] ILLEGAL DATA ADDRESS!

[KHSaville]

It took a while to learn Rapid Scada but well worth it.
We need to read modbus registers from a gas meter, electric meter and a Comap generator controller – IS-NT-BB.
Modbus RTU on serial line with rs485 converter works perfect.
However I am unable to get TCP to work with the Comap.
They require -“Every Modbus/TCP session has to be started with writing the access code from the Modbus/TCP client to the controller. If the session is closed and reopened again the access code must be written again” I am trying to send access code 0 (zero) and cannot get this to work. I send command 7 to 6339 – can you help? If I use a free easy Modbus client it works.

[Mikhail]

Could you provide an example of correct communication? I mean content of packets.
Many controllers support disabling of protection by a code.

[KHSaville]

With Rapid Scada
Send (12): 00 00 00 00 00 06 01 03 00 0D 00 01
Receive (7/7): 00 00 00 00 00 03 01
Receive (2/2): 83 02
Device error: [02] ILLEGAL DATA ADDRESS!
with easy modbus client
Tx: 00 03 00 00 00 06 01 06 18 C2 00 00
Rx: 00 03 00 00 00 06 01 06 18 C2 00 00
Tx: 00 04 00 00 00 06 01 03 00 0D 00 01
Rx: 00 04 00 00 00 05 01 03 02 01 69
Tx: 00 05 00 00 00 06 01 03 00 0D 00 01
Rx: 00 05 00 00 00 05 01 03 02 01 69
Tx: 00 06 00 00 00 06 01 03 00 0D 00 01
Rx: 00 06 00 00 00 05 01 03 02 01 69
My problem is I am unable to send the access code – my error is either Output channel number 1 but where do I put “Command number” and set the value 0 (zero).
https://drive.google.com/open?id=1szde5yIYuH2lN-DjpSX6dy1VWSSolxc5

[KHSaville]

If I do not sent the access code – it fails as with Rapid Scada
Tx: 00 09 00 00 00 06 01 03 00 0D 00 01 – read holding register
Rx: 00 09 00 00 00 03 01 83 02 – rejected
Tx: 00 0A 00 00 00 06 01 03 00 0D 00 01 – read holding register
Rx: 00 0A 00 00 00 03 01 83 02 – rejected
Tx: 00 0B 00 00 00 06 01 06 18 C2 00 00 – write single register
Rx: 00 0B 00 00 00 06 01 06 18 C2 00 00
Tx: 00 0C 00 00 00 06 01 03 00 0D 00 01 – read holding register
Rx: 00 0C 00 00 00 05 01 03 02 01 69 – correct response!

[Mikhail]

1. “easy modbus client” – is this a library or an application?

2. Talking about Comap: “It is possible to disable requiring the access code in
the configuration web page.” It’s from the manual.

3. We can update the existing Modbus driver to send access code as a custom development.

[KHSaville]

Many thanks again – Happy new year Mikhail!
1.http://easymodbustcp.net/en/ – free app.
2. I will try that.
3. If I can write commands to turn on and off bits, write values to registers
I should be able to write the access code.

[KHSaville]

2. Found it !
WOW – now got a talking Comap !
You Sir, are a hero.

[Mikhail]

🙂

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