Sensor wiring - PENN Controls - MR534AFDN - MR534AFDV - Electronic Refrigeration, Defrost, and Multi-Purpose Controller - MR5xx Panel‐Mount Refrigeration and Defrost Controller

MR5 Series Panel Mount Case Controller Installation Guide

PENN Controls
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MR5xx Panel‐Mount Refrigeration and Defrost Controller
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Installation Guide
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See Table 1 for information about the wire gauge required to wire the sensors to the MR5 Controller.

Observe the following guidelines before you wire the sensors to the MR5 Controller:

  • Sensor leads are not color coded or polarity-specific.
  • Keep the sensor leads as short as possible in your application. Additional resistance in long sensor cables can create an offset between the actual temperature and the displayed temperature.
  • It is best practice to use a 0.33 mm2 (22 AWG) stranded twisted-pair shielded cable and wire size.
  • It is best practice to use solder connections. Alternatively, use butt splice connectors. Do not use wire nuts to connect the sensor leads to extension leads.
Important: When you connect sensors with shielded cable to an MR5 controller, connect the cable shield drain lead to one of the C terminals on the sensor input terminal block. Do not connect the shield at any other point along the cable. Isolate and insulate the shield drain at the sensor end of the cable. Connecting a cable shield at more than one point can enable transient currents to flow through the sensor cable shield, which can cause erratic control operation.

Table 1 shows the wire gauge and maximum sensor wire length when you extend A99 sensor wire leads in the field.

Table 1. Maximum sensor cable lengths and wire sizes
Wire gauge Maximum sensor cable length
1.3 mm2 (16 AWG) 150 m (492 ft.)
0.82 mm2 (18 AWG) 100 m (328 ft.)
0.52 mm2 (20 AWG) 60 m (196 ft.)
0.33 mm2 (22 AWG) 40 m (131 ft.)