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GS-AQOPM Series
Wiring Instructions
The sensor has standard screw block connectors and easy wire access to facilitate wiring. It is recommended that
shielded twisted pair wiring at least 22 AWG be used for all connections and that the device wires not be run in the
same conduit with wiring used to supply inductive loads such as motors. Disconnect the power supply before making
any connections to prevent electrical shock or equipment damage. Make all connections in accordance with national
and local electrical codes.
The device should be connected to a 24Vac/dc, class 2 power supply. The PWR terminal is used for the positive DC
voltage or the hot side of the AC voltage. The device is reverse voltage protected and as such will not operate if con-
nected backwards.
The common of the power supply is connected to the terminal marked COM. Note that this device has a half-wave type
power supply which means the power supply common is the same as the output signal common. Therefore, several
devices may be connected to one power supply and the output signals all share the same signal common. Use caution
when grounding the secondary of an ac transformer or when wiring multiple devices to ensure that the circuit ground
point is the same on all devices and the controller. In general, the transformer should not be connected to earth ground
when using devices with an RS-485 network connection.
The analog output signal is available on the OUT terminal. This signal is jumper selectable for either voltage or 4-20 mA
output signal type. See Figure 6. The voltage output signal defaults to 0-5 Vdc but may be changed to 0-10 Vdc via the
menu. These options are clearly indicated on the device PCB. The analog output signal is typically connected directly to
the Building Automation System (B.A.S.) and used as a control parameter or for logging purposes. Check the controller
Analog Input type to determine the correct connection and signal type before applying power. The device generates
the analog output signal (sourcing) and must not be connected to a
powered input or device damage may occur.
For voltage type output signal the device has a minimum load that
it is able to drive, similarly for current type output signal the device
has a maximum load that it is able to drive with a particular power
supply voltage. Observe and follow these ratings in the Specica-
tion section or inaccurate reading may result. The 4-20 mA output
signal can easily be converted to a 1-5 Vdc signal for controllers
accepting this type of input. Simply insert a 250 ohm (0.1% is best)
resistor between the “+” and “-” inputs of the controller. This will
convert the 4-20 mA signal to the desired 1-5 Vdc. See Figure 7.
If the device includes the optional network connection, use twist-
ed shielded pair to connect to the terminals marked A-, B+ and SH
(SHIELD). The positive wire connects to B+, the negative to A- and
the cable shield must be connected to the SH terminal on each
device. The shield wire should be connected to earth ground at one
end of the network only. If the device is installed at either end of
an RS-485 network, an end-of-line (EOL) termination resistor (121
Ω) should be installed in parallel with the A- and B+ terminals. See
Figure 8. This device includes a network termination resistor and
jumper that can be used to connect the EOL resistor on the PCB.
Simply move the jumper to the EOL position and no external resis-
tor is required. See Figure 9.
A network segment is a single shielded wire loop run between
several devices (nodes) in a daisy chain conguration. The total
segment length should be less than 1220 meters (4000 feet) and
the maximum number of nodes on one segment length is 128.
Nodes are any device connected to the loop and include controllers
but do not include the EOL terminators. To install more than 128
devices, or to increase network length, repeaters will be required
for proper communication. The maximum daisy chain length (seg-
ment) depends on transmission speed (baud rate), wire size and
number of nodes. If communication is slow or unreliable, it may be
necessary to wire two daisy chains to the controller with a repeater
for each segment.
