Figure 5. four-wire rtd connections on one channel, Taking measurements from two-wire rtds, Figure 6. two-wire rtd connections on one channel – National Instruments FP-RTD-122 User Manual

Page 6: Measuring resistance directly

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FP-RTD-122 and cFP-RTD-122

6

ni.com

Figure 5. Four-Wire RTD Connections on One Channel

Taking Measurements from Two-Wire RTDs

Connect either wire of a two-wire RTD to the EX+ terminal and the
other wire to the COM terminal, and connect a short jumper wire
between the COM and SENSE terminals.

Figure 6. Two-Wire RTD Connections on One Channel

Measuring Resistance Directly

You can use the [c]FP-RTD-122 to measure resistance in ohms.
In this way, you can take measurements from RTDs of types that
the [c]FP-RTD-122 does not directly support (such as 120

Ω nickel

RTDs) and from resistive devices other than RTDs. You can choose
one of two resistance ranges: 0–400 and 0–4,000

Ω. Resistance

values outside the range you select, including open circuits, result
in an

Out of range

error for the affected channels. The

[c]FP-RTD-122 ignores any configuration of RTD type for
channels with resistance ranges selected.

4-wire RTD

[c]FP-RTD-122

Leave this wire

unconnected

EX+

SENSE

COM

2-wire RTD

EX+

SENSE

COM

[c]FP-RTD-122

Short Jumper Wire

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