Meriam M2110P, Руководство пользователя, Страница: 10 / 32

10
6. Zero Reference
Zeroing the gauge consists of accepting the current pressure value as the zero pressure reference. To set the
zero reference pressure, all pressure sources should be disconnected from the gauge, and its temperature should
be stable.
The pressure reading of the gauge is linearly offset from the zero reference value. Absolute-Isolated pressure
sensors are theoretically zero-referenced to absolute zero pressure (perfect vacuum), and cannot be re-zeroed
without a vacuum source.
AFFECT ON OUTPUTS
The SetPoint and Current Loop outputs are calculated based on the displayed pressure. Since re-
zeroing the gauge may change the displayed pressure, the outputs may change accordingly. For safety
purposes, an extra step is required to warn the operator and confirm the desired action. For clarity,
both scenarios are described below, step-by-step.
FACTORY ZERO
The “Factory Zero” can be restored through the serial port service only (SetPoint and Current Loop
models only). This is the value set during calibration of the sensor, and is typically 0.0.
RANGE CHECK
The M2110P can be zeroed only when the applied pressure is within
±
5% of full scale. If the applied
pressure is greater than 5% of full scale, an error code will be displayed when zeroing is attempted.
STEP BY STEP: RE-ZEROING THE GAUGE (Disabled Outputs, P5=0)
Step Action Display
1
Gauge should be in normal Measure Mode , and the
applied pressure is ready for zeroing (typically
vented, or vacuumed for absolute sensors).
Normal pressure display, near 0.0.
Press the Up
↑
and Down
↓
keys simultaneously. 2
If the lockout is active, the gauge will now prompt for entry of
the lockout code. Refer to “STEP BY STEP: ENTERING A
LOCKOUT CODE (When Prompted)” on page 22.
The display will flash “ 0000 ” several times while
the new zero is taken, and then return to Measure
Mode with the new zero activated.
WHEN OUTPUTS ARE ACTIVE (P5>0) ...
1
Gauge should be in normal Measure Mode , and the
applied pressure is ready for zeroing (typically
vented, or vacuumed for absolute sensors).
Normal pressure display, near 0.0.
Press the Up
↑
and Down
↓
keys simultaneously.
2
If the lockout is active, the gauge will now prompt for entry of
the lockout code. Refer to “STEP BY STEP: ENTERING A
LOCKOUT CODE (When Prompted)” on page 22.
The display will begin countdown from
“
0005 ” to “ 0000 ”.
SetPoint and Current
Loop models only