Delay from alarm fired to alarm sounding?

[paulparry]

Hello All,

How can I set a timer for an alarm, so that a condition has to be true for at least x seconds before the alarm fires? we have duty / standby pumps that switch over every now and again, and when they switch the system shows a fault for about 2 seconds until the other pump comes online. It is annoying having the alarm sound everytime the pumps switch over duty.

Any help much appreciated.

Cheers

Paul

[AzeoTech]

You use a little boolean trick. Lets say you want the alarm to trigger if the last 10 readings of MyChannel are > 5:

min(mychannel[0,9] > 5)

mychannel[0,9] is an array with the last 10 values.

mychannel[0,9] > 5 is an array of 1's and 0's with 10 elements. There is a 1 everywhere it is > 5, and 0 where it is not.

Doing min() on that array tells us if any of the elements are < 5. If so, min() will return 0. If not, then the array is filled with 1's and so min() returns 1 and the alarm fires.

[paulparry]

Many thanks for that, I assume that you enter this in the 'expression'?

I will experiment and let you know.

Cheers

Paul

[AzeoTech]

Yes, that would go in the fire expression. You might use something similar for the reset expression.