Helios PD2-6080/PD2-6081 Modbus
®
Scanners
Instruction Manual
48
Pump Alternation Control Operation
Relay Operation After Communications Break
When a Master scanner fails to receive a reply from the slave it is called a Communications Break. The relays can be
programmed to react to this event by going On, Off, or No Action. After communication is restored the relays are
turned off or on, based on their operating mode and their set and reset points, without regard to their prior state. This
is similar to the auto initialization on power up. Below is a diagram showing three examples.
The same is true for a scanner set up to operate in Snooper mode.
Relay 1
Manual mode
Relay 2
Manual mode
Input
de-energized
energized
Relay 3
Auto mode
Relay 1 Set
Relay 1 to 3
Reset
Relay 2 Set
Relay 3 Set
Communications
Break
Communications
Restored
No Serial
Communications
Communications
Break: No Action
Communications
Break: Relay "on"
Communications
Break: Relay "on"
