How Do I Configure Relay Switching Thresholds?

Dali relays have 4 configurable thresholds to adjust the relay state based on the arc level heard.  These thresholds represent 2 following scenarios, each having a value that will cause the relay to turn on and a value that will turn the relay off:

1.  The arc power has increased and has crossed or is now equal to a value specified.  (up switch on and up switch off)

2.  The arc power has decreased and has crossed or is now equal to a value specified.  (down switch on and down switch off).

If a threshold is set to 255, it is disabled from being evaluated.  Up thresholds can be set from 1-254 (or 255 for disabled.  Down thresholds can be set from 0-254 (255 for disabled).

Switching thresholds are checked when the arc power specified in the value is hit or exceeded. 

For example, if arc power is currently at 1 and we hear an arc power 5, the switching thresholds will be checked for an up threshold that is at value 2, 3, 4 or 5.

As previously mentioned the direction of the arc power change denotes which thresholds to check. 

Dali default example:

The dali default is for up switch on to be set to 1 and down switch off to be set to 0.  The other two thresholds are disabled.

If the relay is currently at arc power 0, any arc level request to the device or a group that it is a member of (including 1) will cause the relay turn on.  This is because the arc power has gone up and has crossed or is equal to the up switch on threshold.

Any further increase in arc power will have no bearing unless the up switch off threshold is set to a value other than 255.  

If the arc power is returned to zero, the down switch off threshold will be triggered and the relay will turn off.

Example requirement:

Customer requires that the relay is only on if the arc power is above or equal to 250.

We must ensure that both directions or arc power changes are handled.

Our up switch on threshold will be 250.

Our down switch off  threshold will be 249.

The other two thresholds (up switch off and down switch on) will not be required, since we do not require the relay to turn off when we increase the arc power, nor do we require the relay to turn on when the arc power is decreased.