How to disable and enable the 1Wire bus (M503)



  • Hi @tomasknot

    I'll come back to this topic again. Is it possible to do the same for Modbus in M503? I mean reset the bus (disable/enable)

    Br,
    Vesa


  • administrators

    Hello @vesa-kauppinen,
    yes, check our Modbus Registers Maps: https://kb.unipi.technology/files:products:02-neuron

    For M503 it is coil 1001 - Enable/Disable 1Wire Bus

    Best regards,
    Martin



  • @martin-kudláček

    Hi,

    That's what we've done with 1-Wire and it works.

    I mean, is it possible to do this same 'reset' for Modbus (RTU) itself? We sometimes lose a modbus device.

    Br,
    Vesa


  • administrators

    Oh, sorry for the misunderstanding @vesa-kauppinen.

    We have a functionality called Master Watch Dog (MWD). When enabled, the underlying HW will watch when the last communication happend. If it will be longer than the preset time, it will reboot itself. Now, this can be set per group in the PLC, and it will watch if the ModbusTCP server communicates with the given group. If not, the board will reboot. Similarly, this can be set on the extensions as well. If nothing communicates with the extension over ModbusRTU, the extension reboots itself.

    This can be set via modbus. Look for the "Enable MWD" coil and "MWD timeout" register. The timeout is in miliseconds.

    Best regards,
    Martin



  • @martin-kudláček

    Thank you!

    Can you give a noob example of how to set 'MWD Enable' to 1 with pollmb.py?

    Br,
    Vesa


  • administrators

    @vesa-kauppinen

    Sorry, I've never used the pollmb.py. Would be the mbpoll example sufficient? You can install the mbpoll from our repository: apt update && apt install mbpoll

    Martin



  • @martin-kudláček

    Yes. If you can give mbpoll example that would be great!

    :)

    Br,
    Vesa


  • administrators

    @vesa-kauppinen

    For Group 1 on M503

    Verify the status of the MWD (if 0 - MWD disable, if 1 - MWD enabled but never rebooted, if 2 - MWD enabled and already rebooted):
    mbpoll -m tcp -a 0 127.0.0.1 -0 -1 -r 6

    Set the MWD timeout to 5000ms:
    mbpoll -m tcp -a 0 127.0.0.1 -0 -r 1008 5000

    Enable the MWD:
    mbpoll -m tcp -a 0 127.0.0.1 -0 -r 6 1

    Write the settings to the NVRAM:
    mbpoll -m tcp -a 0 127.0.0.1 -0 -t 0 -r 1003 1

    Verify the MWD by stopping the UniPi Modbus TCP server:
    sudo systemctl stop unipitcp

    The both lines of LEDs should blink for 1sec after the MWD timeout

    Disable the MWD:
    mbpoll -m tcp -a 0 127.0.0.1 -0 -r 6 0

    Write the settings to the NVRAM:
    mbpoll -m tcp -a 0 127.0.0.1 -0 -t 0 -r 1003 1

    For Group 2 on M503
    Use the MWD control register 114 instead of 6
    Use the MWD timeout register 1108 instead of 1008
    Use the Save configuration coil 1103 instead of 1003



  • @martin-kudláček

    Thanks for the good instructions! After enabling MWD, setting timeout and writing the settings:

    mbpoll -m tcp -a 0 127.0.0.1 -0 -1 -r 6
    mbpoll 1.2-6 - FieldTalk(tm) Modbus(R) Master Simulator
    Copyright (c) 2015 epsilonRT, All rights reserved.
    This software is governed by the CeCILL license <http://www.cecill.info>
    
    Protocol configuration: Modbus TCP
    Slave configuration...: address = [0]
                            start reference = 6, count = 1
    Communication.........: 127.0.0.1, port 502, t/o 1.00 s, poll rate 1000 ms
    Data type.............: 16-bit register, output (holding) register table
    
    -- Polling slave 0...
    [6]:    3
    

    ...or...

    mbpoll -m tcp -a 0 127.0.0.1 -0 -1 -r 114
    mbpoll 1.2-6 - FieldTalk(tm) Modbus(R) Master Simulator
    Copyright (c) 2015 epsilonRT, All rights reserved.
    This software is governed by the CeCILL license <http://www.cecill.info>
    
    Protocol configuration: Modbus TCP
    Slave configuration...: address = [0]
                            start reference = 114, count = 1
    Communication.........: 127.0.0.1, port 502, t/o 1.00 s, poll rate 1000 ms
    Data type.............: 16-bit register, output (holding) register table
    
    -- Polling slave 0...
    [114]:  3
    

    What does that result (3) mean? Its not 0, 1 or 2.

    Btw

    sudo systemctl stop unipitcp
    

    should be

    sudo systemctl stop neurontcp
    

    in Neuron M503...right??

    Br,
    Vesa


  • administrators

    Hi @vesa-kauppinen,
    sorry the value 3 is 1 + 2, which means board has MWD enabled and the MWD already rebooted the board.

    The service is called unipitcp, but in older packages it was called neurontcp. The service is the same for Neurons and Axons, so we renamed it to unipitcp to make it more clear.

    Best regards,
    Martin



  • @martin-kudláček

    Aaaaa...of course :D

    But what about this: either 11 or 3

    root@residevice:~# mbpoll -m tcp -a 0 127.0.0.1 -0 -1 -r 6
    mbpoll 1.2-6 - FieldTalk(tm) Modbus(R) Master Simulator
    Copyright (c) 2015 epsilonRT, All rights reserved.
    This software is governed by the CeCILL license <http://www.cecill.info>
    
    Protocol configuration: Modbus TCP
    Slave configuration...: address = [0]
                            start reference = 6, count = 1
    Communication.........: 127.0.0.1, port 502, t/o 1.00 s, poll rate 1000 ms
    Data type.............: 16-bit register, output (holding) register table
    
    -- Polling slave 0...
    [6]:    11
    
    root@residevice:~# mbpoll -m tcp -a 0 127.0.0.1 -0 -1 -r 6
    mbpoll 1.2-6 - FieldTalk(tm) Modbus(R) Master Simulator
    Copyright (c) 2015 epsilonRT, All rights reserved.
    This software is governed by the CeCILL license <http://www.cecill.info>
    
    Protocol configuration: Modbus TCP
    Slave configuration...: address = [0]
                            start reference = 6, count = 1
    Communication.........: 127.0.0.1, port 502, t/o 1.00 s, poll rate 1000 ms
    Data type.............: 16-bit register, output (holding) register table
    
    -- Polling slave 0...
    [6]:    3
    
    root@residevice:~# mbpoll -m tcp -a 0 127.0.0.1 -0 -1 -r 6
    mbpoll 1.2-6 - FieldTalk(tm) Modbus(R) Master Simulator
    Copyright (c) 2015 epsilonRT, All rights reserved.
    This software is governed by the CeCILL license <http://www.cecill.info>
    
    Protocol configuration: Modbus TCP
    Slave configuration...: address = [0]
                            start reference = 6, count = 1
    Communication.........: 127.0.0.1, port 502, t/o 1.00 s, poll rate 1000 ms
    Data type.............: 16-bit register, output (holding) register table
    
    -- Polling slave 0...
    [6]:    11
    

    Br,
    Vesa


  • administrators

    @vesa-kauppinen

    Ok, this is a little bit tricky. The register has 16bits, and some of the bits represent some state or function.

    Bit 0: Set or read the status of the MWD
    Bit 1: The MWD rebooted the boarde
    other bits contain some debug information, which we haven't documented yet

    So value 11 in decimal is 0000 0000 0000 1011 in binary. The bit no. 0 (first from the right) is 1, which means MWD is enabled. The bit no. 1 (second from the right) is 1, which means MWD already rebooted the board. Other bits don't apply to you.

    You can "mask" the lowest 2 bits with boolean operation AND, typically with bit mask in hexadecimal representation:

    register_6 && 0x0003

    Or with binary mask:

    register_6 && 0b11

    I hope this helps you.
    Martin



  • @martin-kudláček

    Okay. This clarified the case :)

    Thank you!

    Br,
    Vesa



  • @martin-kudláček

    Hi...again

    One more stupid question: How do I reset 1-wire bus with mbpoll?

    I mean, how can i "convert" those commands:

    ./pollmb.py -p 502 -u 1 -f 5 -a 1001 -q 1 -d 1
    ./pollmb.py -p 502 -u 1 -f 5 -a 1001 -q 1 -d 0
    

    to mbpoll "format". I just don't understand how to read/write coils with mbpoll.

    Thank you!
    Vesa


  • administrators

    Hi @vesa-kauppinen,
    writing 1 to coil 1001:

    mbpoll -m tcp -a 0 127.0.0.1 -t 0 -0 -r 1001 1

    Writing 0:

    mbpoll -m tcp -a 0 127.0.0.1 -t 0 -0 -r 1001 0

    You can learn more from the quite detailed help of the mbpoll:

    mbpoll -h

    Regards,
    Martin