Chapter 4 Features and Functions

Temperature Measurement Configuration

RTD Measurements

To connect an RTD to the module’s screw terminals, see page 21.

∙The instrument supports RTDs with α = 0.00385 (DIN / IEC 751) or α = 0.00391 using ITS-90 software conversions. The default is

α = 0.00385.

∙The resistance of an RTD is nominal at 0 °C and is referred to as R0. The instrument can measure RTDs with R0 values from 49Ω to 2.1 kΩ. The default is R0 = 100Ω.

∙“PT100” is a special label that is sometimes used to refer to an RTD with α = 0.00385 and R0 = 100Ω.

∙You can measure RTDs using a 2-wire or 4-wire measurement method. The 4-wire method provides the most accurate way to measure small resistances. Connection lead resistance is automatically removed using the 4-wire method.

∙For 4-wire RTD measurements, the instrument automatically pairs channel n with channel n+10 (34901A) or n+8 (34902A) to provide the source and sense connections. For example, make the source connections to the HI and LO terminals on channel 2 and the sense connections to the HI and LO terminals on channel 12.

∙Front-Panel Operation: To select the 2-wire or 4-wire RTD function for the active channel, choose the following items.

TEMPERATURE , RTD , RTD 4W

To select the nominal resistance (R0) for the active channel, choose the following item.

Ro:100.000,0 OHM

To select the RTD type (α = 0.00385 or 0.00391) for the active channel, choose the following item.

ALPHA 0.00385

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