Models 947, 948 and 960 Leak Detectors Operations and Service Manual
4-30
4.2.8.5 Test Port Pressure Gauge (TC1) Calibration
This procedure allows for calibration of the test port pressure thermocouple gauge (TC1).
Both the Vacuum and Atmospheric Calibrations procedures must be performed in the order
written. The vacuum calibration is factory set. Do not change this setting unless you have
the appropriate equipment.
NOTE
The calibration of the test port thermocouple (TC1) gauge is
factory set and requires the use of a reference TC and a PC.
4.2.8.6 Vacuum (Low Pressure) Calibration
To perform this procedure:
1. Verify that the leak detector is in the READY condition (the NOT READY LED is
not
illuminated) and that the test port plug is in place.
2. If the system is not already in VENT mode, press the
VENT
button and verify that the
VENT LED is illuminated.
3. Remove the plug from the test port and place a T-Manifold (1 1/8 inches [28 mm] OD)
into the test port.
4. Attach a Tuning Leak (Varian P/N K1608301) and a 531 Thermocouple Gauge Tube
(Varian P/N F0472301) as a reference TC to the T-manifold.
5. Connect the reference TC to an 801 Thermocouple Gauge Controller.
For 120 VAC, order Varian P/N F2739301; for 230 VAC, order Varian P/N F2739302.
6. Wait approximately five minutes for the vacuum system pressure to stabilize.
7. Adjust the Tuning Leak to 100 mTorr as indicated by the Varian 801 and verify that the
test port pressure on the test port pressure graph reads 1.0E-01 Torr.
8. Connect a PC to J1 inside the turret in place of the Service Pendant.
If using HyperTerminal (or equivalent), establish communication with the leak detector.
Refer to:
❑
“Communications Protocol” on page C-1 for the communication parameter setup
❑
“Inputs and Outputs” on page D-1
❑
