Control Slave actuator via HA

[wave68runner]

Hi,
Is it possible to control an actuator configured as slave (SLA) directly from Home Assistant, independently of its main actuator?
My goal is to keep the normal MyHome master/slave relationship, while allowing HA to switch only the slave without affecting the main actuator.
My use case is a bathroom extractor fan: MyHome would control it normally, but HA could keep the fan running longer when needed.
I could use two separate contacts, one for the MyHome slave function and one for HA, but using a single contact of my F411 would be much better.
Would this configuration be possible?
Thanks!

[GreenGrassBlueOcean]

Hi @wave68runner,

Could we take one discussion at a time? I just wrote a detailed reply on your previous discussion (#819) — maybe we can follow up and close that one first before starting new ones, so we can keep things focused. Once #819 is wrapped up, happy to come right back to this one!

[GreenGrassBlueOcean]

Hi @wave68runner,

Thank you for your patience while we followed up on your thermoregulation questions in #819!

To give you the direct answer right away:

1. Is it possible to control an actuator configured as M=SLA directly from Home Assistant without affecting the master?
   No — on the physical SCS bus, an actuator configured with M=SLA shares the identical A and PL address with its master. Any command sent to that address on the bus turns both devices on simultaneously.
2. Can you achieve your exact use case (bathroom light + extractor fan with smart overrun) using a single contact on your F411, without wiring two contacts in parallel?
   Yes, absolutely! In fact, this is one of the most common and rewarding automations to set up with Home Assistant.

Here is the breakdown of why M=SLA behaves this way, and how to configure your F411 with a single contact for the fan.

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1. Why M=SLA Cannot Be Controlled Independently

In BTicino MyHome physical configuration:

• A slave actuator (M=SLA) is assigned the exact same A and PL configurators as the master actuator it follows (e.g. both are configured as A=1, PL=1).
• The OpenWebNet protocol addresses points on the bus by Area and Point Light (*1*WHAT*A*PL##). There is no sub-address parameter in OpenWebNet to target only the slave relay.
• When an ON frame (*1*1*11##) is transmitted on the SCS bus, both physical relays hear the telegram and close their contacts.
• Status feedback (*#1*11##) is only answered by the master; the slave does not report independent state.

Therefore, as long as an actuator relay is configured as an SCS hardware slave (M=SLA) sharing the master's address, it is physically impossible for the gateway or Home Assistant to command the fan without also turning on the light.

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2. The Solution: Decouple the Addresses on the F411 (Single Contact!)

You do not need two separate contacts wired in parallel. You can do this cleanly with a single contact on your F411 by decoupling its address from the light:

Step 1: Physical / Virtual Configuration

On your F411 (e.g. F411/2 or F411/4):

• Output 1 (Bathroom Light): Configure as A=1, PL1=1, M = [empty].
• Output 2 (Extractor Fan): Configure with its own distinct Point address, e.g.:
  A=1, PL2=2, M = [empty] (remove the SLA configurator).

(If you configure via MyHOME Suite rather than physical plugs, simply assign Output 2 its own PL number and set its Mode to standard Actuator instead of Slave).

Step 2: In Home Assistant

Home Assistant will now discover two independent entities:

• light.bathroom_light (at address 11)
• switch.bathroom_fan (at address 12, discovered as light/switch; you can use Show As: Fan in the UI settings)

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3. The Automation: Smart Overrun & Humidity Boost

Now, Home Assistant handles the master/slave relationship with far more intelligence than physical configurators ever could:

A. Basic Follower with Overrun Timer

When someone turns on the bathroom light at the wall switch, the fan turns on. When they turn the light off, the fan stays on for an extra 10 minutes:

automation:
  - alias: "Bathroom Fan - Follow Light with Overrun"
    id: bathroom_fan_follow_light
    mode: restart
    triggers:
      - trigger: state
        entity_id: light.bathroom_light
        to: "on"
      - trigger: state
        entity_id: light.bathroom_light
        to: "off"
    actions:
      - choose:
          # Light turned ON -> Start Fan
          - conditions:
              - condition: state
                entity_id: light.bathroom_light
                state: "on"
            sequence:
              - action: switch.turn_on
                target:
                  entity_id: switch.bathroom_fan

          # Light turned OFF -> Run fan for 10 min, then turn OFF
          - conditions:
              - condition: state
                entity_id: light.bathroom_light
                state: "off"
            sequence:
              # Tip: using the native MyHOME hardware bus timer ensures the fan
              # turns off on the bus even if Home Assistant restarts during the 10 min!
              - action: myhome.turn_on_timed
                target:
                  entity_id: switch.bathroom_fan
                data:
                  minutes: 10

B. Independent Extra Run Time (e.g. Humidity Purge)

Because the fan has its own address (12), Home Assistant can also turn on the fan at any time without touching the bathroom light — for example, when a humidity sensor detects a shower, or via a dashboard tile / button:

automation:
  - alias: "Bathroom Fan - High Humidity Purge"
    id: bathroom_fan_humidity_purge
    triggers:
      - trigger: numeric_state
        entity_id: sensor.bathroom_humidity
        above: 70
    actions:
      - action: switch.turn_on
        target:
          entity_id: switch.bathroom_fan

---

Summary Comparison

Approach	F411 Contacts Used	Can HA Run Fan Independently?	Notes
SLA on same address (A=1, PL=1, M=SLA)	1	❌ No	Turning on fan always turns on light
Two contacts in parallel	2	⚠️ Yes, but wasteful	Wastes an F411 relay channel
Decoupled addresses + HA automation (Recommended)	1	✅ Yes	Full control, smart overrun, humidity triggers

We have also documented this exact design pattern in our Use Cases documentation (Use Case 11) (tracked in PR #874). Let us know if you need any help mapping your F411 channels!