The Industrial Raspberry Pi Forum

Posted: **28 Nov 2018, 10:11**

We use Revpi core 3 connected two Revpi DIO,in Pictory,we give the Revpi core 3 for virtual Modbus tcp slave,the slave have 32 inputs and 32 output,and the two Revpi DIO also have 32 inputs and 32 outputs totally.How do we match the virtual Modbus tcp Master and physical DIO modules?

Posted: **28 Nov 2018, 14:17**

You can use a simple Python program to mirror the IOs of your devices.

The easiest solution is this little Python program, which mirrors your IOs using a dictionary with piCtory names. If the input value of "I_1" of die DIO is True, than the program will write a "1" to "Output_15" which you can read with Modbus. If you write a value >0 to an Input of the ModbusSlave, than the associated Output of the DIO will be set to True.

This is a kind of 1:1 mirroring if you use the 34/32 mode for the DIOs in piCtory. If you use 19/17 mode, all 16 Bits of Input / Output will be available as one Word, which you can mirror to just one input / output of Modbus, but you have to split this bits with your ModbusMaster.

Code: Select all

#!/usr/bin/python3
# -*- coding: utf-8 -*-
"""Modbus IO-mirror."""
__author__ = "Sven Sager"
__copyright__ = "Copyright (C) 2018 Sven Sager"
__license__ = "GPLv3"
import revpimodio2


def cleanup():
    u"""Clean IOs of RevPi."""
    rpi.core.a1green.value = False


def cycle(ct):
    u"""Cycle to mirror the IOs."""

    # Flash A1 led just to see the program is running
    rpi.core.a1green.value = ct.flag10c

    # Mirror data
    for input_name in dict_io_map:
        rpi.io[dict_io_map[input_name]].value = int(rpi.io[input_name].value)


# Create RevPiModIO and pass cleanup function
rpi = revpimodio2.RevPiModIO(autorefresh=True)
rpi.handlesignalend(cleanup)

# Create IO mapping input: output
# The names are the names which you define on piCtory!
dict_io_map = {

    # DIO 1 inputs to first 14 Outputs of ModbusMaster
    "I_1_i09": "Output_1",
    "I_2_i09": "Output_2",
    "I_3_i09": "Output_3",
    "I_4_i09": "Output_4",
    "I_5_i09": "Output_5",
    "I_6_i09": "Output_6",
    "I_7_i09": "Output_7",
    "I_8_i09": "Output_8",
    "I_9_i09": "Output_9",
    "I_10_i09": "Output_10",
    "I_11_i09": "Output_11",
    "I_12_i09": "Output_12",
    "I_13_i09": "Output_13",
    "I_14_i09": "Output_14",

    # DIO 2 inputs to next 14 Outputs of ModbusMaster
    "I_1": "Output_15",
    "I_2": "Output_16",
    "I_3": "Output_17",
    "I_4": "Output_18",
    "I_5": "Output_19",
    "I_6": "Output_20",
    "I_7": "Output_21",
    "I_8": "Output_22",
    "I_9": "Output_23",
    "I_10": "Output_24",
    "I_11": "Output_25",
    "I_12": "Output_26",
    "I_13": "Output_27",
    "I_14": "Output_28",

    # First 14 inputs of ModbusMaster to DIO 1
    "Input_1": "O_1_i09",
    "Input_2": "O_2_i09",
    "Input_3": "O_3_i09",
    "Input_4": "O_4_i09",
    "Input_5": "O_5_i09",
    "Input_6": "O_6_i09",
    "Input_7": "O_7_i09",
    "Input_8": "O_8_i09",
    "Input_9": "O_9_i09",
    "Input_10": "O_10_i09",
    "Input_11": "O_11_i09",
    "Input_12": "O_12_i09",
    "Input_13": "O_13_i09",
    "Input_14": "O_14_i09",

    # Next 14 inputs of ModbusMaster to DIO 2
    "Input_15": "O_1",
    "Input_16": "O_2",
    "Input_17": "O_3",
    "Input_18": "O_4",
    "Input_19": "O_5",
    "Input_20": "O_6",
    "Input_21": "O_7",
    "Input_22": "O_8",
    "Input_23": "O_9",
    "Input_24": "O_10",
    "Input_25": "O_11",
    "Input_26": "O_12",
    "Input_27": "O_13",
    "Input_28": "O_14",
}

# Start mirroring
rpi.cycleloop(cycle)

To transfair, start and watch the program, you can install RevPiPyLoad. The daemon will execute it on Revolution Pi startup and let it run all the time: https://revpimodio.org/en/revpipyplc-2/

Sven

Posted: **18 Jun 2021, 09:26**

nice example ! it should be saved in download section

Posted: **20 Jul 2021, 12:19**

Nice example! Thank you.

Is there also a code snipped for the other direction? To set outputs externally via modbus.

The Industrial Raspberry Pi Forum

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