Quick Guide ______________________________________________________________________________ PDT102
© Vaisala 2015. All rights reserved. __________________________________________________________________ 2
ELECTRICAL WIRING
PDT102 with voltage output operates on any supply voltage between
12...36 VDC drawing less than 10 mA (24 VDC typical).
Use of a shielded cable, with the shield grounded, is required. Do not connect
the shield to the transmitter. Maximum cable length for voltage output wiring
is 30 m (98.4 ft).
+
–
+
–
POWER
SUPPLY
Figure 3
Voltage Output Wiring
The voltage required for a 4...20 mA output is dependent on the loop
resistance of the circuit. Refer to Figure 5 showing the minimum supply
voltage (Vmin) required for a given Loop Resistance (RL).
+
–
R
S
POWER
SUPPLY
Figure 4
Current Output Wiring
0
10 12
20
30
36
40
1250
1091
1000
750
500
250
0
545
24
Loop Resistance (Ω)
Supply
Voltage (V)
Vmin = 34V+ [0244A*(R L)]
*includes a 10% safety factor
RL = RS + RW
RL = Loop Resistance (ohms)
RS = Sense Resistance (ohms)
RW = Wire Resistance (ohms)
Figure 5
Load Limitations
FRONT ACCESS TEST JACKS (OPTION)
The front access test jacks provide on-line process reference signal or
calibration signal without disconnecting power supply wiring. Measurements
can be made using a standard multimeter. Reference signals through the test
jacks are made in series for 4...20 mA output and in parallel for voltage
output.
Gold plated contacts accept standard 0.08˝ microtip test leads, snapping in
place for secure measurements.
PROCESS VALVE ACTUATOR (OPTION)
The process valve actuator option includes the process valve actuator,
actuator tool, and 7˝ of silicon tubing. The actuator tool identifies the
Calibration (CAL) and Monitoring (MON) modes, and has ports for the (HI)
and (LO) pressure references. From the (OFF) position the actuator tool can
be inserted and removed.
-
In the CAL mode the PDT102 is isolated from the process and allows
externally generated test pressure input for calibration.
-
In the MON mode the system pressures can be monitored using a
handheld pressure instrument without physically unplugging the process
tubes. In this mode an on-line measurement can be captured. Using the
front access test jacks, a reference signal can also be captured without
process interruption.
CALIBRATION
Calibration should be performed after installation and after 100 days from
installation. Yearly recalibration is recommended.
1.
Pneumatically connect the transmitter’s pressure ports to each other. If the
transmitter has the process valve actuator option, rotate it clockwise 90
degrees to isolate the PDT102 from the process, and short the HI and LO
ports on the actuator tool using the silicon tubing supplied.
2.
Measure the analog output of the transmitter to establish the zero offset.
3.
If the reading is not at the middle of the output range (for example, 12 mA
for 4 … 20 mA output), the zero point of the transmitter has shifted. To
remove the zero shift, adjust the transmitter as described below.
ADJUSTMENT
Note:
You need a high accuracy pressure standard and high quality electrical
meter to adjust the PDT102.
1.
Connect the pressure standard to the ports of the PDT102.
2.
Bring the pressure to 0 % of the transmitter’s span (-50 Pa or -0.25 in H
2
O,
depending on model).
3.
Adjust the zero potentiometer on the front of the transmitter so that the
analog output value is at the low end of its range. Use a 3/32” or 2.5 mm
slotted or Phillips screwdriver to turn the potentiometer.
4.
Now bring the pressure to 100 % of the transmitter’s span (+50 Pa or
+0.25 in H
2
O, depending on model).
5.
Adjust the span potentiometer on the front of the transmitter so that the
analog output value is at the high end of its range.
WARRANTY
For warranty information, visit our Internet pages at:
DISPOSAL
Dispose of the unit according to local regulations. Do not dispose of
with regular household waste. Recycle all applicable material.
