Precision Digital PD6080 - Manual (Page 51)

PD6080/PD6081 Super Snooper Modbus Scanner Instruction Manual
51
Programming Set (set) & Reset (rst) Points
High alarm indication: program set point above reset point.
Low alarm indication: program set point below reset point.
The deadband is defined as the difference between set and reset points. Minimum deadband is one
display count. If the set and reset points are programmed with the same value, the relay will reset one
count below the set point.
Note: Changes are not saved until the reset point has been accepted.
Setting Fail-Safe Operation (failsf)
In fail-safe mode of operation, the relay coil is energized when the process variable is within safe limits
and the relay coil is de-energized when the alarm condition exists. The fail-safe operation is set
independently for each relay. Select on to enable or select off to disable fail-safe operation.
Programming Time Delay (delay)
The On and Off time delays may be programmed for each relay between 0 and 999.9 seconds. The
relays will transfer only after the condition has been maintained for the corresponding time delay.
The On time delay is associated with the set point.
The Off time delay is associated with the reset point.
Relay Action for Communications Break (break)
The Scanner will poll the slave device three times before reporting a communications break condition.
After the third failure, the Response Timeout timer starts and will determine the actual time to report a PV
in break condition.
1. Turn On (Go to alarm condition)
2. Turn Off (Go to non-alarm condition)
3. No Action (The relays will maintain the last condition)
Relay Action for Loss of 4-20 mA Input (Loop Break)
The loop break feature is associated with the 4-20 mA input. Each relay may be programmed to go to one
of the above conditions when the scanner detects the loss of the input signal (i.e. < 0.005 mA).
Notes:
1. This is not dependent on the Communications Break or Response Timeout setting.
2. This is not a true loop break condition; if the signal drops below 0.005 mA, it is interpreted as a
“loop break” condition.