American Magnetics 135 & 136 Liquid Helium Level Instruments (CE-Marked) - Manual (Page 30)

18 Rev. 3
Operation
Normal Operational Mode
c. In addition to the LED functions, the controller output
receptacle may be energized and de-energized as discussed in
step 5 below.
Note
The A setpoint must always be above the B setpoint. The firmware
does not allow these setpoints to be reversed. Both setpoints may be
set from 0% to 100% of the LENGTH setting as long as A > B.
3.2.5 Select the operational mode of the controller output receptacle
The operation of the CONTROLLER OUTPUT receptacle of the
instrument is controlled by the fill toggle switch. Operation of the fill
toggle switch is as follows:
a. CLOSED (or OFF): With the power on and the fill switch in the
CLOSED position, the instrument serves only as a level
monitor, giving a level reading on the digital display and
providing data via any analog or communication options
installed. All four setpoint LEDs (and associated J2 connector
relay contacts) operate normally, however, the controller output
receptacle on the rear panel will always be de-energized.
b. OPEN (or ON): With the fill switch in the OPEN position, the
rear panel CONTROLLER OUTPUT receptacle will become
energized, thereby initiating flow if the solenoid-operated fill
valve is properly connected. The FILL LED on the front panel
will light indicating the presence of power at the controller
output receptacle. The operator is solely responsible for
terminating the fill flow.
c. AUTO: With the fill switch in the AUTO position, the
instrument is capable of automatically initiating and
terminating liquid fill via the control valve, thereby
maintaining the level between the selected A and B setpoints. If
the liquid level falls below the B setpoint, the rear panel
CONTROLLER OUTPUT receptacle and front panel FILL LED
are energized. When the liquid level subsequently reaches or
exceeds the A setpoint, the controller output receptacle is de-
energized and the FILL LED is extinguished.
Note
The Model 136 has precautionary measures programmed for cases
where the sensor may be accidently disconnected. If the sensor is
disconnected, the level reading will be 100% after the next
measurement, which effectively de-energizes the controller output if
operating in the AUTO mode.
0RGHO