American Magnetics 187 Self-Compensating Liquid Level Controller - Manual (Page 26)

15
Operation
Operational Guidelines
3.1.4 Configuring the HI and LO Alarms
To adjust the HI and LO alarm levels, use the HI and LO menus accessible
by using the
‡+, and ‡/2 keys, respectively. The setpoints may be
located anywhere between 0% to 100% of the measured span. The HI and
LO alarm adjustments are compatible with all three units modes.
a. When the measured liquid level exceeds the HI alarm, the HI
LED on the front panel is energized and a set of relay contacts
are closed on the 9-pin D-sub connector J8 on the rear panel
(see the Appendix for the pinout). When the level reaches or
falls below the HI alarm, the LED is extinguished and the relay
contacts open.
b. When the measured liquid level falls below the LO setpoint, the
LO LEVEL LED on the front panel is energized and a set of
relay contacts are closed on the 9-pin D-sub connector J8 on the
rear panel (see the Appendix for the pinout). When the level
reaches or exceeds the LO setpoint, the LED is extinguished
and the contacts open.
Note
The HI and LO contacts are both closed on power-off of the
instrument which is a state unique to the power-off condition.
Note
If the length settings are adjusted subsequent to configuring the
various settings, the percentage of the measured span will be
maintained for all alarms or setpoints. For example, if the measured
span is set to 100 cm and the HI alarm is set to 80 cm, then
adjusting the measured span to 150 cm will result in the HI alarm
being automatically scaled to 120 cm—i.e. the setting of 80% of the
measured span is retained.
3.1.5 Configuring the A and B Setpoints
The A and B setpoints, which specify the upper and lower limits for the
liquid level control band, are accessible via the
‡$ and ‡% keys. The A
and B setpoint adjustments are compatible with all three units modes.
a. When the measured liquid level reaches or exceeds the A
setpoint, the A LED on the front panel is energized. When the
level falls below the A setpoint, the LED is extinguished.
b. When the measured liquid level falls below the B setpoint, the B
LED on the front panel is energized. When the level reaches or
exceeds the B setpoint, the LED is extinguished.