Reading register from Siemens LOGO! PLC via ModBus

Configuration
1

Hi, I’m trying to read one of the analog inputs from my PLC

Does anyone what to put into the config-file to be able to read the “AI” inputs?

image

anything that will help me will be much appreciated.

1 Like
2

Hello @fesklord,

I have a LOGO where input registers are temperatures, they are short integer so if I read 321 it means 32.1°C.

I divide my configuration.yaml so I have to edit 3 files:

  • configuration.yaml:

    modbus: !include modbus.yaml
template: !include templates.yaml

  • modbus.yaml (please note the host is your LOGO IP address, I store mine in the secrets.yaml file):

    - name: "Siemens LOGO"
  type: tcp
  host: !sercret siemens_logo_ip
  port: 502
  sensors:
    - name: "MyLOGO1"
      unique_id: mylogo1
      input_type: input
      slave: 1
      address: 0
      count: 8
      data_type: custom
      structure: ">8h"

    Note: structure:">8h" means I have reading 8 short number of 2 bytes each with big endian ending. You can read about Python structure here.

  • As I read all 8 input registers at once and then use a template to separate the values, then I have less modbus requests made to the LOGO. So I divide the values in templates.yaml:

    - name: Heater temperature
  state: "{{ states('sensor.mylogo1').split(',')[0] | multiply(0.1) }}"
  state_class: measurement
  unit_of_measurement: °C
- name: External temperature
  state: "{{ states('sensor.mylogo1').split(',')[1] | multiply(0.1) }}"
  state_class: measurement
  unit_of_measurement: °C
# and so on until states('sensor.mylogo1').split(',')[7]

I hope that helps and do not hesitate to reach out if you have any question.

3

@cloom, thank you!

1 Like