3
Features and Functions
138
Keysight 34980A Mainframe User’s Guide
RTD Measurements
The instrument supports RTDs with
α
= 0.00385 (DIN/IEC 751) using ITS-90
software conversions or
α
= 0.00391 using IPTS-68 software conversions. The
default is
α
= 0.00385.
– The resistance of an RTD is nominal at 0 °C and is referred to as R
0
.
The instrument can measure RTDs with R
0
values from 49
Ω
to 2.1 k
Ω
.
– 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
in
Bank 1 with channel
n+20
in Bank 2 (34921A, 34923A) or
n+35
(34922A,
34924A) to provide the source and sense connections. For example, make the
source connections to the HI and LO terminals on channel 2 in Bank 1 and the
sense connections to the HI and LO terminals on channel 22 (or 37) in Bank 2.
Front Panel Operation:
To select the 2-wire or 4-wire RTD function for the
active channel, choose the following items.
DMM or Channel (Configure) > TEMPERATURE > PROBE TYPE > RTD|4W RTD
To select the RTD type (
α
= 0.00385 or 0.00391) for the active channel, choose
the following item.
RTD TYPE > 0.00391|0.00385
To select the nominal resistance (R
0
) for the active channel, choose the following
item.
RO > 100 OHM
Remote Interface Operation:
You can use the
CONFigure
or
MEASure?
command to select the probe type and RTD type. For example, the following
command configures channel 3001 for 2-wire measurements of an RTD with
α
=
0.00385 (use “85” to specify
α
= 0.00385 or “91” to specify
α
= 0.00391).
CONF:TEMP RTD,85,(@3001)
You can also use the
SENSe
command to select the probe type, RTD type, and
nominal resistance. For example, the following command configures channel 1003
for 4-wire measurements of an RTD with
α
= 0.00391 (channel 1003 is
automatically paired with channel 1023 for the 4-wire measurement).
