[modbus_controller] `offline_skip_updates` works only once when a server goes `offline`

[Sleeper85]

The problem

Hi @0x3333

When a server goes offline, with offline_skip_updates set to 5, 5 requests are skipped and then an indefinite number of requests are sent to the server regardless of the offline_skip_updates setting.

I would expect that after skipping 5 updates, one request would be sent (actually 4 with max_cmd_retries set to 3) and then 5 requests would be skipped again if the server continues to not respond so as not to pollute the bus.

The RS485 bus:

R120ohm---(server 2)-----(server 1)-----(client)-----(server 3)-----(server 241)---R120ohm

Attached are the modbus logs.

logs_register_V2_device_3_offline_2024.12.15.txt

Thank you for your help and the time you spend improving this component.

Which version of ESPHome has the issue?

2024.11.3

What type of installation are you using?

Home Assistant Add-on

Which version of Home Assistant has the issue?

No response

What platform are you using?

ESP32-IDF

Board

esp32doit-devkit-v1

Component causing the issue

modbus_controller

YAML Config

modbus:
  - uart_id: uart_esp_1
    id: modbus_client
    send_wait_time: 250ms

modbus_controller:
  - id: modbus_controller
    modbus_id: modbus_client
    setup_priority: -10
    address: 3
    update_interval: 5s
    command_throttle: 0ms
    max_cmd_retries: 3
    offline_skip_updates: 5

Anything in the logs that might be useful for us?

[23:00:53][W][modbus_controller:027]: Modbus device=3 set offline
[23:00:56][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 5
[23:01:01][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 4
[23:01:06][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 3
[23:01:11][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 2
[23:01:16][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 1
[23:01:21][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 0
[23:01:26][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 0
[23:01:31][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 0
[23:01:36][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 0
[23:01:41][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 0
...
[23:10:41][V][modbus_controller:199]: Range : 1 Size: 20 (4) skip: 0

Additional information

No response

[Anry777]

i have the same issue. Skip works only once

[Sleeper85]

@exciton

Does your PR fix this ?

https://github.com/esphome/esphome/pull/8032

[exciton]

My PR doesn't specifically change the behaviour of skip_updates, but it significantly helps avoid errors on the bus which may cause the problem in the first place. If you have many devices and see CRC errors or timeout errors then my PR will probably fix it.