Torr; Common - HELIX GRANVILLE-PHILLIPS Convectron ATM Instruction Manual

Chapter 3
3.6 Calibrating Convectron
gauge at vacuum
chamber pressure
Figure 3-17 Vacuum chamber pressure calibration test points and potentiometers
CONVECTRON ADJUST
3.7 Modules operating below
–3
10

Torr

36
Periodic resets of the vacuum chamber calibration point improve the
accuracy and repeatability of the Convectron gauge.
Regardless of the process gas that is being used, you should always use N
or air to calibrate the Convectron gauge at vacuum chamber pressure.
1. Turn on the pump and, using N
pressure to descend to a pressure that is lower than 10
2. Refer to Figure 3-17 and use a high-precision, high-input impedance
(Z > 1 MΩ) DVM to measure the voltage across the CONVECTRON
in
ANALOG and COMMON test points on the module front panel.
3. Use a flat-head instrument screwdriver to adjust the CONVECTRON
ADJUST VAC potentiometer to a reading of 0.375 VDC.
CONVECTRON ANALOG
VAC potentiometer
During a fast pumpdown from atmospheric pressure, thermal effects
temporarily prevent the module from measuring pressure accurately below
–3
10 Torr. After approximately 15 minutes, pressure indications the 10
Torr range will be accurate and response will be rapid.
When pressure indication in the 10
Convectron gauge calibration at vacuum chamber pressure may be
performed. The calibration may be performed at a higher pressure if
readings in the 10
resolution is ±0.1 millitorr, if the Convectron gauge has been properly
calibrated at vacuum chamber pressure. If the module frequently operates
in the 10 –4
pressure should be performed frequently.

COMMON

test point test point
–4
Torr range are not required. In the 10
Torr range, Convectron gauge calibration at vacuum chamber
®
Convectron ATM Vacuum Gauge Module Instruction Manual
or air, allow vacuum chamber
2
–4 Torr range has stabilized, a
2
–4 Torr.
–4
–4
Torr range,