6MVE
2.3 Wiring:
Wiring Guidelines:
• Electrical wiring must comply with all applicable
codes
• Use stranded, copper wire/cable with a minimum of
167°F rating (75°C rating).
• Always use insulated, stranded, shielded copper cable
for all communication cables. Refer to individual device
manuals for wiring instructions.
• Do not pull communication wiring with AC power cables.
This can cause electrical interference.
• Use only the existing conduit hole for connections to
each device.
• Bonding between metallic conduit connections is not
automatic with the non-conductive enclosure. Separate
bonding must be provided.
• During installation, cover conduit holes and close the
enclosure cover to prevent debris from falling into the
equipment.
AC Power Wiring:
• Power should be provided by a dedicated 15A circuit
breaker. It is recommended that the circuit breaker be
located near the equipment, and clearly marked as the
disconnect for the MVE gas detection control panel.
• See Specication on page 37 for requirements.
L N
Line
Neutral
Earth Ground
• For 200-240Vac input voltage, the input voltage selector
switch must be switched. The factory setting is 100-
120Vac. It is located on the side of the right power
supply. See illustration on page 11. Red circle shows
location of switch. The switch is located behind the
protective cage of the power supply, but is accessible by
using a small screwdriver or pointy object.
Communication Wiring:
The MVE controller has four Modbus communication
channels. Up to 255 devices can be installed on the MVE,
distributed among the four channels.
It is recommended to pull 24Vdc power cable with the
communication cables. These cables can share the same
conduit.
• RS-485 communication cable, 22-24 AWG, 2 conductor,
twisted pair, shielded, stranded, with drain wire (Alpha
Wire 6460 or Quabbin 8302 or equivalent)
• 4,000 ft max per channel.
• For optimum performance, it is recommended that no
more than 128 devices are connected on any of the four
channels.
• For optimum performance, CTI recommends that the
MVE controller is always at the end of the line. When the
MVE controller is at the end of the line, the EOL switches
should always be set to the ON position.
• Avoid splices and T-taps. All terminations should be
made at network device wire terminals
• Wire shields must be connected at all shield terminals,
creating a continuous shield run from the controller to
the device at the end of the line.
B A GND SHLD
To rst device
SHIELD
not used
A
B
COM 1
Terminal Block Plug (Field Wiring):
SHLD: To shield terminal of rst network device.
GND: Not used
A: To RS-485-A terminals of rst network device.
B: To RS-485-B terminals of rst network device.
See DuoSense-M and MVFD installation manuals for more
details on communication wiring.
Each device has a communication port with two terminals,
A and B. In these two terminals, the communication
cable is connected so that all the devices that take part in
the communication are connected in parallel. All of the
‘A’ terminals must be connected together and all the ‘B’
terminals must be connected together, respectively.
