Fisher 244EH, 244ER manual Sensor Connections, RTD or Ohm Inputs

Figure 2-11. Transmitter Field Wiring Diagrams

Use the following steps to wire the transmitter:

1.Connect the positive lead from the power supply to the transmitter terminal marked “+” and the negative lead to the transmitter terminal marked “–” (see Figure 2-11and Figure 2-13).

2.Tighten the terminal compression screws to ensure adequate contact. No additional power wiring is required.

3.After making connections, recheck the polarity and correctness of connections, then turn the power on.

Model 244EH

Power0000A02C

Supply

-244

Model 244ER

Power0000A02D

Supply

-644

Note: Signal loop may be grounded at any point or left ungrounded.

Sensor Connections

The Models 244E are compatible with a number of RTD and thermocouple sensor types. Figure 2-12shows the correct input connections to the sensor terminals on the transmitter. To ensure proper sensor connections, anchor the sensor lead wires into the appropriate compression terminals and tighten the screws.

RTD or Ohm Inputs

The transmitters will accept a variety of RTD configurations, including 2-wire, 3-wire, 4-wire, and compensation loop designs. If the transmitter is mounted remotely from a 3-wire or 4-wire RTD, it will operate within specifications, without recalibration, for lead wire resistances of up to 10 ohms per lead (equivalent to 1,000 feet of

20AWG wire). In this case, the leads between the RTD and transmitter should be shielded. If using only two leads, both RTD leads are in series with the sensor element, so significant errors can occur if the lead lengths exceed three feet of 20 AWG wire (approximately 0.05 °C/ft). For longer runs, attach a third or fourth lead as described above.

2-13