IPT
2
8
The Interface Solution Experts
IPT
CURRENT/PRESSURE
TRANSMITTER
+IN –IN
P
2
+T
–T
Adjustab
le
Current
Source
Load
(See
Tab
le 2)
M2
M1
Regulated
Instr
ument
Air Supply
+
–
Pressure
Gauge
±0.1%
Pressure
Gauge
±2%
Pressure
Out
Pressure
In
+IN
–IN
+T
–T
Figure 3.
Calibration Setup
Test Jacks
The +T and –T test jacks on the front of the IPT
2
are provided as a convenient means of monitoring
the process loop to which the product is connected
without disconnecting the unit or interrupting the loop.
A milliammeter connected to the +T and –T test jacks
will provide a reading in the range of the unit's output
rating (Figure 3). The model number of the IPT
2
shows its output range.
Caution:
The maximum resistance the milliammeter can
introduce into the test jack circuit and still provide
accurate readings is 10
Ω
.
If the milliammeter readings are not as anticipated,
verify that the milliammeter is rated for no more than
10Ω impedance. If the unit is suspect of improper
operation, remove it from the test jacks and calibrate
the IPT
2
.
Calibration Setup
Figure 3 is an illustration of a typical calibration setup,
including optional equipment. To check or calibrate
the IPT
2
, connect the unit as shown in this illustration.
Calibration Procedure
There are two options shown in Figure 3 for
monitoring the output of the IPT
2
. The input current
may be measured by placing a milliammeter in
series with the input terminals as indicated by M1
or connected across the electrical test jacks by a
milliameter of less than 10Ω impedance (+T and -T)
as indicated by M2.
1. For zero adjustment, connect an adjustable
current source to the electrical input terminal
block. Set the current input signal for zero
percent output (e.g. 4mA for a 4-20mA input,
3-15psig output; 20mA for a 4-20mA input, 15-
3psig reverse output).
Note:
Observe that the red LED indicator on
the front panel is illuminated at zero input
current and glows somewhat brighter with
increasing current.
2. Using an air pressure gauge to measure the input
air supply pressure, connect a fi ltered air supply
to the pneumatic supply port located on the
bottom or rear of the unit.
3. If the unit is supplied with the optional front-
access pneumatic-output test jack, insert
the pneumatic coupler into the receptacle.
This avoids having to disturb any operating
connections or fi ttings.