INSTRUMENT MANUAL
VACUUM GAUGE MODEL MM200
160Phone:(215) 947-2500 fax:(215) 947-7464 e-mail:sales@televac.com web site:www.televac.com
MM-200_im REV M
Page 128 of 160
TELEVAC
700 CALIBRATION
701 ELECTRICAL "VERIFICATION" OF VACUUM MEASURING
INSTRUMENTS ON VACUUM CHAMBERS
An electrical "verification" of a Televac vacuum measuring instrument provides a way to assure that the vacuum
measuring instrument installed on the vacuum chamber is in electrical agreement with Televac's "standard"
gauges. Our "standard" gauges are directly traceable to NIST.
Electrical agreement with Televac's "standard" gauges is accomplished through the use of an electronic gauge tube
simulator, which is substituted in place of the gauge tube installed on the vacuum chamber. Such ”verification"
does not in itself assure that the vacuum measured in the chamber is correct, since the gauge tube installed on the
vacuum chamber is bypassed. It does give an electrical check of the vacuum measuring instrument and cable.
EQUIPMENT REQUIRED
In order to use the Field Procedure the following equipment is required.
A. Vacuum Chamber Equipment
Each vacuum furnace should be fitted with an instrument with special features.
1. A "zero adjust" (or "heater adjust") calibration potentiometer for each
thermocouple gauge, located on the rear panel.
2. A 10
-3
Torr calibration adjust potentiometer for the cold cathode, located on
the rear panel.
3. Cold cathode gauge tubes of the latest improved design. (Dual magnet type).
Retrofit existing tubes or replace, if necessary.
B. Electrical Gauge Tube Simulators
The devices used to carry out electrical "verification" of the modular vacuum
instruments are referred to as gauge tube simulators. These devices can be
returned to the Televac factory annually to be recertified. They are listed below.
2-2100-93 Cold cathode tube simulator (10
-3
, 10
-5
Torr)
2-2100-237 2A tube simulator (Set at "Redline")
2-2120-000 4A tube simulator (Set at "Redline")