Gateway ModRTU

Topics about the Hardware of Revolution Pi
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janbob
Posts: 3
Joined: 31 Jul 2018, 12:12
Answers: 0

Gateway ModRTU

Post by janbob »

Hi,
I have several problems with this module.
I can’t find any manual for this module.
How I can define slave address?
I inserted gateway into PiCtory. But there is no possibility to set slave address like e.g. in virtual ModbusRTU Slave?
Why inputs and outputs are organized in bytes and not in words? Modbus registers are words.
In one head of column in table describing switches is “Type, Fs, Term”. What does “Fs” mean?
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dirk
KUNBUS
Posts: 1942
Joined: 15 Dec 2016, 13:19
Answers: 4

Re: Gateway ModRTU

Post by dirk »

Hi Janbob,
please excuse that there is no RevPi Support page for the Gateway Modbus RTU. We will add this as soon as possible.

The manual for the Modbus RTU Gateway Module is available here.
In the user manual the Slave Address is named Node-ID.

If you set the switches to 0,0,0 then you have the default values from page 21.
9600 Baud, 8Bit, Even Parity, 1 Stop Bit, Slave Address 1.

Then for example you may connect to it using modpoll via

Code: Select all

modpoll -a 1 -m rtu -r 4100 -t 4:hex -b 9600 COM1

You may switch the Slave Address to 10 via

Code: Select all

modpoll -a 1 -m rtu -r 4100 -t 4:hex -b 9600 COM1 10

Then you switch the "DR" to 3 in order to use baudrate 9600 with the new Slave Address

Reboot

Code: Select all

modpoll -a 1 -m rtu -r 4096 -t 4:hex -b 9600 COM1 19266

And after reboot you have the Slave Address 10

Code: Select all

modpoll -a 10 -m rtu -r 4100 -t 4:hex -b 9600 COM1

The 1-Byte outputs in PiCtory are there because the Modular Gateways exchange their data with other Modular Gateways or with the RevPi in the little endian format. See chapter 5.3.
Therefore the ModbusRTU registers are mapped on the RevPi to 1 Byte values in little endian format. So the first bytes of data on the RevPi is Reg1 Byte1, Reg1 Byte0, Reg2 Byte1, Reg2 Byte0, etc..

I could not understand what you mean by "FS" ? The three switches have the function to set the bitrate, frame format and type of interface. See chapter 5.2.
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