18
300544660_002_C1
11/2016
- © Leybold
Zero Adjustment
Like all precision electromechanical measuring instruments, the transmitter requires periodic zeroing of its output to
provide the best possible measurement accuracy. Leybold recommends that the transmitter be zeroed upon initial
installation into the user’s process system
to compensate for any drift that may have occurred during transportation
and installation. Subsequent zeroing frequency must be determined by the user according to each application, but
in general, more frequent zeroing should be expected if the transmitter is frequently exposed to atmospheric
pressure, or if it is used in an application where the best measurement repeatability is needed.
To zero the transmitter, the vacuum system must be pumped down to its lowest achievable vacuum pressure,
which ideally
should be less than 0.01% of the transmitter’s full
-scale measurement range. The table below
provides the recommended vacuum pressure needed for each available range.
Once the recommended zeroing pressure has been achieved, the zero pushbutton offers multiple adjustment
modes depending on the customer requirements. The first mode is to set t
he transducer’s output to zero.
Briefly
press the ZERO button with a small diameter rod such as the User switch adjustment tool provided with each
device.
The transducer’s output will shift to zero when this is done. The STATUS LED blinks until the adjustment is
completed. However, if no action is taken within 8 seconds of entering this mode, the STATUS LED stops blinking
and the transducer exits this mode.
Recommended Zeroing Pressure
Torr
mbar
Pascal
≤ 0.1
≤ 0.132
≤ 13.3
≤ 0.01
≤ 0.013
≤ 1.3
≤ 1x 10
-3
≤ 1.3x 10
-3
≤ 0.13
≤ 1x 10
-4
≤ 1.3x 10
-4
≤ 0.013
≤ 1x 10
-5
≤ 1.3x 10
-5
≤ 1.3 x 10
-3
Transmitter Full-Scale
Range - Torr
1000
100
10
1
0.1
Use care when activating the zero pushbutton. It can be easily damaged or even knocked off its
mounting on the electronics by excessive force. If this occurs, the transmitter electronics will not
operate correctly.
Caution
!
!
