KNX Mini presence detector MTN6303-0019 send ON Command when power reset

[IC_Systems]

Hello Team,

A customer reported that the lights remained on and did not turn off after a power reset. This issue occurred because the Mini Presence sensor sent an “on” command when power outage occurred.

To resolve this, you can set the sensor to send the value cyclically as “off,” as shown in the image below.

The question is: Is this the normal operation?

 

[Heribert_Dölger]

Hello

When the Mini Presence Sensor is powered it sends ON command and shortly afterwards OFF. So it seems in your case the switch actuator seems to react to the ON command but not to the OFF. Or the actuator is configured to go to last value after return of KNX bus voltage, and the actuator takes more time to reboot after power return and does see neither ON nor OFF and goes to the last value.

The configuration to send OFF value cyclically indeed would help in this situation. It is a normal setting that can be chosen.

[IC_Systems]

Hello @Heribert_Dölger 

I noticed that the Actuator channel receives an on command before it turn off when the power is disconnected!
means that the on command sent during power off.

Also I see that the Mini presence sent an on command then shortly afterword OFF command after application download not after power reset!
you could see the actuator failure behavior for the desired channel.

You are right the channel configured to go to last value after return of KNX bus voltage, this is the new Spacelogic Master

 

[Heribert_Dölger]

With the setting of the actuator it will come back with the status before power cut. So it will be ON in case it was ON before. In my test the Mini Presence Sensor did not send ON command when I removed it from the KNX power supply. But in that moment it was not detecting presence. Maybe in your case a person was detected shortly before and due to that it had sent ON command.

The ON and OFF is sent after application download and power reset. Strange that you don't see it after power reset. After ETS application download the device is being reset. That's why the same behaviour appears after bus power return.

[IC_Systems]

@Heribert_Dölger 
Do you test on Spacelogic Master Actuator?
I test the case on the office and blind the Motion before disconnecting the power, I noticed an on command sent to the channel during power off, I will do the test again to check.
In your case do you have the same response after power reset and application download.

[Heribert_Dölger]

I am testing without actuator. Just looking at the telegrams on the ETS group monitor.

I can confirm that the ON and OFF sequence is sent after reset and application download.

I do not see an ON command when I cut the KNX bus power. If you have the sensor in a box and remove the KNX connector this might be seen as movement in case you move the device by that operation.

[IC_Systems]

Please take a look on the ETS telegrams 
I did the test by tripping the circuit breaker, the actuator channel was off before test GA 1/1/137 for F/B

the on telegram couldn't be monitored during the power off while the SL still powered and monitoring the bus, but actually the actuator channel is switched on during power off, so because of that you didnt see any on telegram during the power off.

if you could make a real test with Spacelogic actuator connected.

Also, if you see that the reboot time for the Mini Presence is faster than the Spacelogic actuator, the on and off  command sent before the spacelogic even start, so this shouldnt make any issue, but the issue remain during the power off.

appreciate your effort.

 

[Heribert_Dölger]

Indeed it makes a difference how to test. When testing like you (switch OFF the KNX power by circuit breaker) I can see that the Mini Presence detector is sending ON command. The Spacelogic switching actuator receives this command and due to that takes this as the last value.

Also I can confirm that the switching actuator takes more time to reboot. When power returns the Mini sensor send the ON command, few seconds later the OFF command. But the switching actuator does not see these telegrams. Shortly later switching actuator sends feedback value ON as this was the last status.

Configuring cyclical sending of the OFF command of the Mini sensor will help. I configured a cycle time of 5sec and the light then was switched OFF shortly after it was switched ON.

[IC_Systems]

Thank you @Heribert_Dölger 

Appreciate your effort, But do you think that power reset case like power outage from the utility is not similar to switch off power by circuit breaker?

while the customer complain several time, in our countries its usual to have power outage for several minutes every month.

Is it possible to enhance the Mini presence to not send ON Command during the power off?

[Heribert_Dölger · Accepted solution]

Hello again

Your test conditions are fully valid and can happen in real life. I only mentioned the difference to my test conditions because my setup didn't allow to see the ON command of the detector when KNX power disappears.

Unfortunately, this behaviour cannot be eliminated. It is a function inside firmware and there is no parameter to avoid it. And the detector does not have the option to load a different firmware.