Carbon Monoxide Transmitter Modbus
Installation Manual
May 5, 2017
IN-CMD5B4MOD-01-01 Page 1
Introduction
The CO Transmitter uses an electrochemical sensor to monitor the
carbon monoxide level and outputs a field-selectable 4-20 mA or
voltage signal. The voltage signal may also be set to 0-5 or 0-10
Vdc. The sensing range and output may be scaled to either 100,
150, 300, 400 or 500 ppm via the on-board menu. A front panel
LCD is standard to ensure easy setup and operation.
Other standard features include a back light for the LCD, a front
panel test switch, status indication and an alarm buzzer. The test
function may also be controlled remotely with a digital input signal.
A three-key menu is implemented to allow local configuration of all
device parameters.
Optional features include one or two alarm relays and RS-485
network communications configured for either ModBus or BACnet
protocols.
Before Installation
Read these instructions carefully before installing and commissioning the CO Transmitter. Failure to follow these instructions
may result in product damage. Do not use in an explosive or hazardous environment, with combustible or flammable gases,
as a safety or emergency stop device or in any other application where failure of the product could result in personal injury.
Take electrostatic discharge precautions during installation and do not exceed the device ratings.
Mounting
The CO enclosure should be mounted onto a flat surface three to five feet from the floor of the area to be controlled. The
mounting hole locations are shown in the enclosure dimensional drawings. Do not mount the sensor near doors, opening
windows, supply air diffusers or other known air disturbances. Avoid areas with vibrations or rapid temperature changes.
Open the hinged cover by releasing the latch and connect the device according to the wiring instructions. After wiring and
setup are complete, close and latch the cover. The cover may be secured with two self-tapping screws in the holes provided.
Hardware Setup
The only hardware setup required is to select the analog output type with the pcb switch labelled
VOLT
and
mA
. Slide the
switch to the correct position for the required output signal type, either 4-20 mA or 0-5/10 Vdc.
Power and Analog Output Wiring
Use 22 AWG shielded wire for all connections and do not locate the device wires 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 codes.
The wiring configuration depends on the specific model and the installed options. Follow the example wiring diagrams to
determine the correct wiring. All models have the same terminal functions. This device has a half-wave type power supply so
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 so 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 RS-485 network connections.
This is a 3-wire sourcing device. All models require a 24 Vac/dc power supply to operate. Connect the positive dc voltage or
the hot side of the ac voltage to the
ANALOG -
PWR
terminal and the power supply common to the
ANALOG - COM
terminal. Note that the Analog COM terminal is NOT connected to the Relay COM terminals. The device is reverse voltage
protected and will not operate if the power supply is connected backwards.
The linear output signal (either 4-20 mA or 0-5/10 Vdc) is available on the
ANALOG - CO
terminal. The signal is
referenced to the Analog COM terminal. The 4-20 mA output signal operates in the Active mode and does not require a loop
power supply. This means
the signal current is generated by the transmitter and must not be connected to a powered
