Handbook
November 2011
/
59-UMC0071
/
Issue
01
Mercury
iTC
Page 140
LEVEL-METER DAUGHTER BOARD
Original Instructions
13
If required, change the value displayed in the
Pulse Counting Period (ms)
field.
14
Tap
Home
to return to the Home page.
15
If required, access the Channel Display Configuration page and change the
displayed value from
Pulse
to
N2 Level
.
16.4
Specification of the level-meter board
Table 16-2
Environmental specifications of the level meter
Parameter
Specification
Recommended ambient temperature
20°C to 30°C
Ambient temperature (with reduced performance)
0°C to 50°C
Altitude
Up to 2000 m
Vibration
Fixed laboratory installation
Table 16-3
Specification of the helium probe
Parameter
Specification
Excitation current settings
20 mA to 280 mA in 20 mA steps
Excitation current accuracy
±5%
Excitation voltage
40 V maximum
Probe resistance
0
Ω
to 300
Ω
Probe resistance measurement accuracy
±0.2%
Probe resistance measurement stability
±0.1%
Probe resistance ADC measurement resolution
Better than 0.005%
Probe connections isolation to chassis
>50 VDC
Table 16-4
Specification of the nitrogen probe
Parameter
Specification
Probe source voltage
12 VDC
Probe source oscillator frequency range
5 kHz to 65 kHz
Probe sensing resolution (level)
0.1%
Probe sensing accuracy (level)
0.5%