LabVIEW Modbus as master, Automation Direct Click as slave... addressing issue...

[chuggins1434]

Hello one and all,

I'm using LabVIEW as a master and communicating to an Automation Direct Click Plus PLC via Ethernet using Modbus protocols... The issue I'm running into is that my addressing on my target module is far in excess of the 65535 max addressing that I'm getting when I try and put it in.  The starting address I see in the Click programming software is starting at 428673. 

For reference I have the main cpu (Click Plus C2-03CPU), a relay module (C0-08TR-3)... this I can communicate with fine and control the relays without issue as the addressing for it starts at 8225, and then there's my problem child...  ...an analog output module (C0-04DA-2) whos addressing starts at 428673.

Now, I don't know if this is a new set of protocols that weren't planned for when NI Modbus or the Plasmionique Modbus Master library's were developed... or if my Modbus Kung-Fu is exceptionally weak... (this is probably the case to be honest).

I'm at a bit of a loss on how to proceed.  If someone has a suggestion I'd appreciate it!

TIA,

Chad

[PalanivelThiruvenkadam]

Check with different kind of registers

1. Holding Registers

2. Input Registers

3. Discrete Input registers

4. Coils

Based on your read write options between slave and Master you can choose any one (Each Starts with 0)

[tst]

I have no specific experience with this, but you might want to look at this article, specifically at the Data Addressing Ranges section:

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Coils exist with a prefix of 0. This means that a reference of 4001 could refer to either holding register one or coil 4001. For this reason, all new implementations are recommended to use 6-digit addressing with leading zeros, and to note this in the documentation. Thus, holding register one is referenced as 400,001 and coil 4001 is referenced as 004,001.

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Presumably, this would mean it's probably holding register 28673.

[K C]

Hi,

The address you mentioned 428673 is probably a DCS notation.

If you translate that to normal ModBus than this would be function code 3 and decimal address 28672.

DCS starts at 40001. Which is ModBus function code 3 and address 0.

Kees