Hello,
In this example I have a pair of two modules:
- VMBPIRO – mounted outside
- VMB1RYNOS – acting as a control for a contactor
This contactor then turns on or off the heating for rain… whatever those ducts that go downwards are called in order to avoid ice formation within. The goal for the moment is to only enable heating between -2.5°C and 2.5°C. As I can set up the alarms for high and low temperatures almost arbitrarily, I have chosen to set them up as such:
Low Alarm = 2.5°C
High Alarm = -2.5°C
This way, the two alarms will only ever be in a Pressed state at the same time between the temperatures I want to enable heating for. Then following the FAQ: How do I realize logical and advanced functions in velbus? I set up:
VMBPIRO.Low Alarm o--[ 703. Inhibit while initiator is open ]--> VMB1RYNOS.CH1
VMBPIRO.High Alarm o--[ 104. Momentary (follow) ]--> VMB1RYNOS.CH1
This seems to work alright, if all pieces fall into order. Alas, it seems that the state is not correctly computed when modules boot for the first time if this happens while the temperature is higher than 2.5°C! In this situation the High alarm
will switch from Released
to Pressed
on boot and the VMB1RYNOS.CH1
will follow, but the Low alarm
will remain in its initial state of Released
and thus the 702
action will not get applied!
Is this the expected behaviour with the Inhibit while initiator is open
on a fresh boot? If so, is there a better way to implement a Logic AND that would correctly propagate the state on a fresh system boot up? Neither of the two modules have any outstanding firmware updates I could apply.