American Magnetics 110 Liquid Helium Level Meter (CE-Marked) - Manual (Page 19)

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3 Operation
This section describes the front panel display and control functions for the
Model 110A. In addition to the front panel operation described, analog
output signals proportional to the liquid level are provided by rear panel
connectors. Refer to the Appendix beginning on page 17 for more details
regarding the analog outputs.
3.1 Normal Operational Mode
3.1.1 Turn on the power
Turn the power toggle switch to the on position. The green LED located
near the power switch will be energized.
Note
The Model 110A instrument is calibrated at the factory.
No further calibration is required. Please observe the calibration
sticker to verify that the unit is calibrated for the correct active
sensor length.
3.1.2 Read the level display
The Model 110A performs continuous level measurements. Simply observe
the front panel level meter for the current liquid level.
3.1.3 Connect the analog output signal
The connector J1 on the rear of the instrument also provides a 0-10 VDC
or optional 4-20 mA analog signal corresponding to 0-100% of liquid level.
Refer to the Appendix for the pinout diagram of connector J1.
3.2 Contaminated Sensors
AMI expects the helium level sensor to be reasonably clean and free from
oil, water, ice, etc. for proper operation. If correct readings cannot be
obtained, the sensor must be warmed to remove ice, or completely removed
for cleaning or replacement.