Calibrating a P/I Transmitter
9
Table 5. Pump Features
Item Description
Pressure
Vacuum
Switch
Rotate forward (clockwise) for pressure,
backward (counter-clockwise) for
vacuum.
Pressure
Vacuum
Release
Valve
Rotate fully backward (counter-
clockwise) to release all pressure or
vacuum. (Rotate slightly for partial
release.) Rotate fully forward (clockwise)
to close valve.
Fine
Adjustment
Knob
Rotate either direction for precise
adjustment of applied pressure or
vacuum. Full rotation is about 30 turns.
Internal
Pump
Increase pressure on the inward stroke.
In vacuum mode, decrease pressure on
the outward stroke.
Calibrating a P/I Transmitter
To calibrate a P/I (pressure to current) transmitter, apply a
pressure to the transmitter and measure the transmitter’s
current loop output. You can apply pressure with the
Calibrator’s internal pump or with an external pump. An
internal relief valve activates when pressure/vacuum
exceeds the rating for the Calibrator model (50-60 psi for
718 30G, 140-150 psi for 718 100G.)
W Warning
To avoid a violent release of pressure or vacuum,
always depressurize the system slowly using the
pressure/vacuum release control before detaching
any pressure line.
Using the Internal Pump
The internal pump can provide 30 psi (2.0685 bar) for
Model 718 30G or 100 psi (6.895 bar) for Model 718
100G.
The preferred use for the internal pump is shown in Figure
4, where the calibrator displays pressure measured with
the internal sensor and provided by the internal pump.
The internal pump can also be used with certain Fluke
700 Series Pressure Modules. In this case, pressure
measured by the Pressure Module is displayed by the
Calibrator. Appropriate Pressure Modules for each