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.
| 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.) |