ModbusTCP Ingress

Name	ModbusTCP Ingress
Version	v1.0.1
Dockerhub Link	weevenetwork/modbus-tcp-ingress
authors	Jakub Grzelak

• ModbusTCP Ingress
  • Description
  • Supported TCP Functions
  • Environment Variables
    • Module Specific
    • Set by the weeve Agent on the edge-node
  • Dependencies
  • Input
  • Output

Description

This ingress module provides readings from a selected Modbus TCP server.

Supported TCP Functions

The following TCP functions are supported by this module

Modbus Function	Variable Name	Permitted Values
Read Coils	coils	Number of registers to read from must be 1 to 2000
Read Discrete Inputs	discrete_inputs	Number of registers to read from must be 1 to 2000
Read Holding Registers	holding_registers	Number of registers to read from must be 1 to 250
Read Input Registers	input_registers	Number of registers to read from must be 1 to 250

Environment Variables

Module Specific

The following module configurations can be provided in a data service designer section on weeve platform:

Name	Environment Variables	type	Description
Server Host Address	SERVER_HOST_ADDRESS	string	Host address of Modbus TCP Server
Server Host Port	SERVER_HOST_PORT	integer	Port on which the Modbus TCP Server runs
Function	FUNCTION	enum	Modbus Function to apply: coils, discrete_inputs, holding_registers, input_registers
Start Address	START_ADDRESS	integer	Index of the first register to read data from
Length	LENGTH	integer	Number of consecutive registers to read data from (starting from index of above Start Address)
Interval Period	INTERVAL_PERIOD	integer	Data from registers is read every interval period
Interval Unit	INTERVAL_UNIT	emum	Unit for the time interval: ms (miliseconds), s (seconds), m (minute), h (hour), d (day)

Set by the weeve Agent on the edge-node

Other features required for establishing the inter-container communication between modules in a data service are set by weeve agent.

Environment Variables	type	Description
MODULE_NAME	string	Name of the module
MODULE_TYPE	string	Type of the module (Input, Processing, Output)
EGRESS_URLS	string	HTTP ReST endpoint for the next module

Dependencies

requests
pyModbusTCP

Input

Input to this module are data read from registers of Modbus TCP server.

Output

Output of this module is JSON body with selected registers values and following labels:

Output for Coils and Discrete Inputs:

[
    {
        "bit_address": <index of register>,
        "data": <bool value read from register>
    },
]

Output for Holding Registers and Input Registers:

[
    {
        "register_address": <index of register>,
        "data": <integer value read from register>
    }
]

Example for Coils and Discrete Inputs:

[
    {
        "bit_address": 3,
        "data": true
    },
    {
        "bit_address": 4,
        "data": true
    },
   {
        "bit_address": 5,
        "data": false
    },
]

Example for Holding Registers and Input Registers:

[
    {
        "register_address": 0,
        "data": 12
    }
]