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3.2 General Wiring Information
High voltage terminals (120/240 VAC) are located within the DVP-120, presenting a hazard to service technicians. Only qualified
technicians should open the DVP-120 case and service the internal circuits. Ensure power is removed from the DVP-120 prior to servicing
the unit.
With the exception of the safety ground, all field wiring is completed via modular connectors (provided). After wiring, simply plug the
modular connectors into the matching connectors on the printed circuit board (PCB).
Note: It is recommended to always install with wires enclosed within the rigid metallic conduit.
3.2.1
DVP-120
The power and signal connections to the remotely mounted sensors should be size AWG18 (minimum) for short runs. Refer to Table 3-
2 for recommended wire gauges. Four conductor cables may be used in all cases since the DVP-120 employs DC power for remote
sensors to help prevent electrical noise from interfering with the sensor output signal.
Do not bundle sensor power and/or signal connections with other AC power cables to prevent electrical interference. If other AC power
connections must be bundled with the DVP-120 sensor cables, the sensor connections should be made with two twisted pairs of the
appropriate gauge, with an overall foil and braid shield. All shields should be terminated at the DVP-120 end of the cable only. A ground
stud is provided near the bottom left corner of the panel.
3.2.2
DVP-120B
The power connections to the MRS-485 and remote mounted sensors and should be size AWG18 (minimum) for short runs. Refer to
Table 3-2a for recommended wire gauges. The power for the MRS-485 adapter is connected via a two-terminal screw type connector,
12 to 24 VAC or 12 to 24 VDC and no polarity.
The MRS-485 adapter output is wired in the standard 2W-Modbus circuit definition with selectable built-in terminating resistors at the
ends of the RS-485 bus. It is recommended to always use twisted wires to reduce noise and allow for reliable data communication over
greater distances. For best performance use shielded 3-conductor wire with one twisted pair providing a pair for signal (A & B), common
(COM) and shield ground (SHD) connections. Use at least 3-conductor wire with one twisted pair providing a pair for signal (A & B) and
common (COM) connections. The Macurco MRS-485 Modbus output is connected via a four-terminal screw type connector.
Running the Modbus cable adjacent to or in the same conduit with high voltage wires is not recommended as there may be interference
from the high voltages.
WARNING
Figure 3-2 Typical Layout
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