•
pump up control
•
low differential alarm
The
ON
and
OFF
setpoints can not be the same on an individual relay but may be
common to other relays. The deadband or hysteresis is the difference between the
ON
and
OFF
setpoints. For ‘in bound’ and ‘out of bounds’ relay functions, the hysteresis is
±
2 % of span from each setpoint.
The setpoints for level alarm functions 1 - 4 and pump control functions 8 - 10 are
always entered in the P-1 units of measurement selected (
but not %)
. The setpoints are
measured from the bottom up, referenced to zero or empty except for the differential
functions, 4 and 10. There the setpoints represent the absolute differential between
levels, regardless of the level with respect to zero.
Relay status - non run modes
When the fail-safe timer expires, pump control relays respond as previously described.
However, alarm relays will respond in the following manner.
Upon entering the CALIBRATE mode, all pump control relays will be turned OFF.
Alarm relays will hold their prior status, but will respond to measurements take when
“MEAS” is pressed.
Simulation
Parameters P-76 through P-78 can be used to simulate relay operation in the
CALIBRATE mode. Pump relays will be held OFF during simulation, however their
corresponding LED’s will respond. Remote totalizer and flow sampler relay operation
do not apply to simulation. Refer to Section VII.
NOTE
If the relay status can affect plant operation or personnel safety, it is advis-
able to override the relay functions or disconnect the relay wiring during
calibration or simulation.
KEEP POWER DISCONNECTED
AT MAIN BREAKER WHEN
HydroRanger I COVER IS OPENED
fail-safe hold hold
FAIL-SAFE MODE
P-74
RELAY STATUS
fail-safe high on
fail-safe low off
high alarm low alarm
off
on
hold
PL-399 5 – 7
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