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 on the jumpers. Also, review the
specifications to ensure the power supply is correct and that the
pressure is within the correct range. The product should be allowed to
warm-up for several minutes before attempting to verify accuracy.
Allow the device to operate for 20 minutes before any calibration is
performed.
Normal Operation
If the unit is set to a unipolar range such as 0-1 "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 0-1 "wc, 4 mA or 0 V = 0 "wc and 20 mA or 5 V or 10 V = 1 "wc. Since the transmitter is linear, 0.5 "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.
For a bipolar range such as
±
1 "wc, the pressure applied to the High port should be higher than 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 follows:
4-20 mA
Pressure = [(Output current – 4 mA) / 16 mA] x 2 x Range – Offset
0-5 Vdc
Pressure = (Output voltage / 5 V) x 2 x Range – Offset
0-10 Vdc
Pressure = (Output voltage / 10 V) x 2 x Range – Offset
Wiring Instruction (con’t)
Figure 7
Wiring all output signals and
24 Vdc power from controller
Wiring for all output signals and
external 24 Vac power transformer
Wiring for all output signals and
external 24 Vdc power supply
24 Vdc Power Supply
Pneumatic Connections
The two pressure ports on 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 connect-
ed correctly. Use 1/8" to 3/16" ID flexible tubing for the pressure
connections. A flexible silicone tube is recommended. 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. See figure 10.
Figure 10
High Port
Low Port
Operation can be verified by measuring the output signal. For voltage output configuration, measure the voltage between
the PRESS OUT and COMMON terminals. The voltmeter should read between 0-5 or 0-10 Vdc depending on the output range
selected on the DIP switch. For current output configuration, insert a mA meter in series with the PRESS OUT terminal and it
should read between 4 and 20 mA.
1/8” to 3/16” ID
flexible tubing
Figure 8
Relay Output
Remote Zero
Figure 9
Greystone Energy Systems, Inc. 150 English Drive, Moncton, NB E1E 4G7 Canada Tel: +1-506-853-3057 Tollfree (North America): +1-800-561-5611 Fax: +1-506-853-6014
Email: [email protected] Web: www.greystoneenergy.com
