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CONFIGURATION
The transmitter is configured with switches located on the circuit board as shown on the PCB drawing.
These switches are used to select the output signal type and the input pressure range. The unit is factory
configured to operate in the 4-20 mA output mode. This can be changed to the voltage mode by moving
the switch from the position marked 4-20 mA to the position marked Voltage. Once the output mode
is changed to voltage, the output scale may be changed to either 0-5 Vdc or 0-10 Vdc. This is done by
moving the switch to the 5V or 10V position marked 5/10 on the five position DIP switch. The pressure
range is set with a five position DIP switch.
Switch Setting LP-00
LP-01
LP-02
LP-03
LP-04
LP-05
LOW
1" WC
3" WC
6" WC
10" WC
0.25" kPa
0.5 kPa
MID
2" WC
5" WC
10" WC
15" WC
0.5" WC
1 kPa
HIGH
4" WC
8" WC
12" WC
20" WC
1 kPa
2 kPa
For example, if the LOW range is selected on the LPS-00 model, the pressure range will be 0-1” wc. If the
4th DIP switch labeled (+/-) is also set to ON, then the pressure range will be –1 to +1” wc. This means
that each model has six pressure ranges. For the LPS-00 they will be 0-1, 0-2, 0-4, ± 1, ± 2 and ± 4 “wc. Set
LOW, MID or HIGH DIP switch to ON to select desired range. Note: If no range is selected LCD will display
"Err" indicating no range selected.
PNEUMATIC CONNECTIONS
The two pressure ports on the end of the enclosure are labeled High and Low. The output signal reads a
positive value when the port pressure is higher on the High port than the Low port so ensure these ports
are connected correctly. Use 0.170” I.D. flexible tubing for the pressure connections. Arrange the tubing
to minimize stress on the connections and ensure there are no kinks in the tubing. For most accurate
measurements, do not leave the Low port open to the atmosphere, run a return line from the Low port
to the vicinity of the point being measured.
Ensure the tubing to be used is clean and do not allow material to fall into the pressure ports as
contamination could damage the sensor. When removing tubing use care to avoid breaking the ports. In
some cases it is better to cut the tubing off rather than pulling it off but be careful not to cut the fitting or
an air leak may occur.
POWER UP INSTRUCTION
Before turning on the power, verify all wiring to ensure that it complies with one of the included wiring
diagrams and verify that the output signal type is correctly selected with the switches. Also, review the
specifications to ensure the power supply is correct and that the pressure is within the correct range.
At this time, also inspect the internal pressure tubing that connects the sensor to the external ports to
ensure that the tubing did not get kinked during shipping or installation.
Proper operation can be verified by measuring the output signal. For voltage output configuration,
measure the voltage between the OUT and COM terminals. The voltmeter should read between 0-5
Vdc or 0-10 Vdc depending on the output range selected. For current output configuration, insert a mA
meter in series with the OUT terminal. The mA meter should read between 4 and 20 mA.
OPERATION
If the unit is set to a unipolar range such as 0-2” wc, then the pressure applied to the High port must be
higher than the pressure applied to the Low port. In this case, if the Low port is left open to ambient
pressure and the High port is used to measure a positive pressure, then the output pressure can be
calculated as follows:
4-20 mA
Pressure = [(Output current - 4 mA) / 16 mA] x Range
0-5 Vdc
Pressure = (Output voltage / 5 V) x Range
0-10 Vdc
Pressure = (Output voltage / 10 V) x Range
In the case of 0-2” wc, 4 mA or 0 V = 0” wc and 20 mA or 5 V or 10 V = 2” wc. Since the transmitter is linear,
1” wc would be 12 mA or 2.5 V or 5 V. If the positive pressure connection is reversed then the transmitter
will always output 4 mA or 0 V.
If the unit is set to a bipolar range such as ± 2” wc, then the pressure applied to the High port should be
higher than the pressure applied to the Low port for a positive output response. In this case, differential
pressure can be measured using both ports. If the High port has a positive pressure with respect to
the Low port, then the output indicates a positive pressure. Negative pressure is indicated if the High
pressure is less than the Low pressure. For bipolar ranges, the output pressure can be calculated as
IN-GE-LPXXXS-02
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