5 | Baker Hughes
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Calibration with the Test Jack:
Connect pin 1 of the Jack Plug to the positive (+) lead of the
current calibrator and pin 3 of the Jack Plug to the negative (-)
lead of the current calibrator and then insert the Jack Plug into the
Test Jack. The current calibrator is now the input signal source.
Calibrate as stated above. Removing the Jack Plug will return
operation of the unit back over to the original current source.
Figure 4
Monitoring with the Test Jack:
Connect pin 1 of the Jack Plug to the negative (-) lead of the
ammeter and pin 2 of the Jack Plug to the positive (+) lead of
the ammeter. Insert the Jack Plug into the Test Jack and use the
ammeter to monitor the input current loop�
Tight Shut-Off Adjustment
Instructions
Figure 5
The Tight Shut-Off potentiometer can be adjusted to set the zero
point at which the instrument ‘shuts off’.
For Example:
Tight shut-off is deactivated in the factory.
Figure 6
Setting of shut-off point:
1. With the instrument under test connected to the required
supply pressure and load ports, apply a demand current
signal of that value at which shut-off is required.
2. If the output pressure is >start-up pressure (~0psi), adjust
potentiometer slowly clockwise until the output pressure
falls to zero. Do not turn the pot beyond this point. The shut-
off point is now set.
Shut-off point check:
Increase the input signal by approximately 0.5mA (e.g. to 3.8mA)
the output pressure will rise above 0psi. Reset the input signal to
the required shut off point (e.g. 3.3mA) and the output pressure
will fall to zero.
Simple Functional Checks
Apply a 4-20mA signal and an air supply of 30psig and observe
the output on a pressure gauge. It should control smoothly. The
Test Jack can also be connected as a monitor measure.
Problem
Possible Causes
Suggested
Action
Maximum
output
not available
Supply pressure
too low
Check and adjust
supply
Calibration error
Recalibrate
Air leak in
instrument
Locate leak and
repair
Excess outlet flow
Check with
specification
Minimum output
too high
Calibration error
Replace
Recalibrate
Delay on
start up
A delay of a few
seconds is normal
None
Erratic
operation at low
pressure
Signal currents
below 3.5mA are
insufficient for
normal operation
Increase current
May need
recalibration
Tight shut-off set
No output
available
Tight shut off
potentiometer
adjusted
Turn until a
pressure output
is observed
on gauge or
pressure sensor
Erratic at all
pressures
Controller cannot
provide 6.5V
continuously
Reduce loop
resistance or
change controller
Contamination
Check I/P filter
status
