Precision Digital PD865 - Manual (Page 11)

PD865 Snooper Modbus Serial Input Meter Instruction Manual
11
Relays
RATING Standard: 2 relays, SPST (Form A)
Optional: 2 relays, SPDT (Form C)
All relays are rated 3 A @ 30 VDC or 3 A @ 250 VAC,
resistive loads.
ELECTRICAL
NOISE
SUPPRESSION A suppressor (snubber) should be connected to each relay
contact switching inductive loads to prevent disruption to
the microprocessor’s operation. Recommended suppressor
value: 0.01 µF/470
, 250 VAC (PDX6901).
DEADBAND 0-100% of full scale, user selectable
HIGH OR LOW
ALARM User may program any alarm for high or low trip point.
RELAY
OPERATION Automatic (non-latching)
Latching
Pump alternation control (up to 4 relays)
RELAY RESET User selectable via front panel buttons or Modbus control
Automatic reset only (non-latching)
Automatic + manual reset at any time (non-latching)
Manual reset only, at any time (latching)
Manual reset only after alarm condition has cleared (latching)
Automatic reset: Relays will automatically reset when the
input passes the reset point.
Manual reset: Front panel ACK button. Pressing ACK
resets all manually resettable relays.
TIME DELAY 0 to 199 seconds, on and off delays
Programmable and independent for each relay
FAIL-SAFE
OPERATION Programmable
Independent for each relay
COMMUNICA-
TIONS BREAK No change, Relay on, or Relay off.
Controls the condition the relay goes to when a slave
device does not reply (Available also in Slave mode v1.1 &
up).
AUTO
INITIALIZATION When power is applied to the meter, relays will reflect the
state of the input to the meter.
Fail-safe operation: relay coil is energized in non-alarm condition. In case of
power failure, relay will go to alarm state.