Cbus Light sensor switching metal halide lighting

I am looking for some advice.
I have installed a cbus light sensor to control a 4 channel relay for metal halide lights in a warehouse.

I am getting a lot of nuisance switching when clouds pass over due to huge varations in lux levels. I have set a large margin already. I cant really set the margin any more otherwise the lights wont come on till too late at sunset. Is there anyway that i can set the relay or the sensor to delay the switch on as what i am experiencing is a sudden drop of below 200 lux for a short period of time due to heavy cloud which passes pretty quickly. Which instantly causes the lights to switch on and then off a few minutes later when the lux level rises back up to 500 plus. I am concerned that this is shortening the life of the lamps.

 

Hello colmac.
Do you have a touchscreen or PAC to run logic in?

 

I have a PAC

 

Find a better spot for your PE cell..

 

Its not the location of the sensor that's the issue. the whole warehouse experiences the same difference in lux

 

Create a group called, say, 'sensor disable'. Select this group in the sunset to sunrise function. Set the timer to say 10 minutes. Select the same group in the sensor enable/disable box and check 'disables'. When the light level goes low this will disable the sensor for the specified time.

Disclaimer: I haven't actually tried this

 

Ok so at what approx lux at sunset do you wish for the lights to come on at?
200 is still pretty bright..
The australian standard for warehouses is 150 lux on the workplane..
Depending on the location of the sensor and the levels it is presenting i would be setting it to on/off control with 155 lux with a margin of 10%.. So the load will get turned on when lux drops below 140 lux and will turn off again at when light level exceeds 170 lux..

 

Same as others I haven't tried this but it may help.

Rather than using 'Light On/Off', try using the 'Light Level' option. Then on your relay change your 'turn on threshold' to 75 or 100%.

As the light level option ramps the level rather than just turning it on and off it should give you a delay in the on and off of the fixture. The delay will be dependent on the light change and the level of your threshold. By playing around you may find a good delay time where, within the time it takes to get to 75% the clouds have passed and it starts to ramp down again without turning on the lights.

 

Another option, using logic:
Use a group, maybe called "Lights on by sensor" in the light level sensor.
Use a group, "Lights" on your relay channel.

Code:

// Sensor calls for lighting to be turned on.
once
 (GetLightingState("Lights on by sensor") = ON) then
begin
 TimerSet(1, 1); //Start timer.
end;

// Turn lights on if still needed after 30 seconds.
once
 TimerTime(1) > 30 then
begin
 SetLightingState("Lights", ON);
 TimerSet(1, -1); // reset timer
end;

// Sensor calls for lighting to be turned off.
once
 (GetLightingState("Lights on by sensor") = OFF) then
begin
 SetLightingState("Lights", OFF);
 TimerSet(1, -1); // reset timer
end; 

I'm tapping this one out on the iPad , so syntax may not be 100% correct but hopefully you get the idea.