Chemglass AF-0304 - Manual (Page 6)

1.4. Dual Set Point Controller
The Dual Set Point Controller instruments are combina-
tion controller and indicator digital vacuum gauges. The
controllers power a Pirani-type gauge tube which senses
changes in pressure by measuring the thermal conduc-
tivity of the residual gases in the vacuum system. The
sensors are made of an inert, noble metal that does not
oxidize or corrode. The long-term life expectancy for the
gauge tube is excellent if kept clean and free of oil or
other evaporated contaminates from the vacuum system.
In addition to acting as a digital indicator, the Dual Set
Point Controller instrument operates two control relays.
Set point pressures are set from the front panel and
displayed on the meter. Push-to-set switches simplify
display of the set points. Relays have 3 amp contacts,
form C, and are terminated in screw terminal connectors
on the rear. The mating half of the relay connector is
provided.
The instrument is powered from a 115 VAC or 230 VAC
line as specified when ordering. Power consumption is
about 2 Watts. Either 50 or 60 Hz power may be used.
A 10 foot long gauge tube cable is attached and exten-
sions up to 500 feet (if using #18 wire) may be added
without affecting calibration. See section titled, “Cable
Extensions” for more information.
Installation of the controller is identical to the Digital
Indicator except for wiring the relay connectors for the
control action. This is described in the section titled,
“Relay Output Connector Wiring.”
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