Keithley 3721-ST User Manual

Section 11: TSP command reference Series 3700A System Switch/Multimeter Reference Manual
11-220 3700AS-901-01 Rev. D/June 2018
dmm.rtdalpha
This attribute contains the alpha value of a user-defined RTD.
Type
TSP-Link accessible
Affected by
Where saved
Default value
Attribute (RW)
Yes
Reset
DMM reset
Recall setup
Create configuration script
Save setup
3.850550E-03
Usage
value = dmm.rtdalpha
dmm.rtdalpha = value
value
The RTD alpha value; the range is 0 to 0.01
Details
This attribute is only valid when dmm.func is set to "temperature". All other functions generate an
error and return nil when queried.
This setting only applies when the transducer type is set to 3 or 4-wire RTD. For other transducer
types, the setting is set but not used until the transducer type is set to an RTD type.
The RTD alpha setting is saved with the dmm.func function setting, so if you use another function,
then return to "temperature", the RTD alpha setting you set previously is retained.
The following attributes share common settings and apply to both 3 and 4-wire RTDs:
dmm.rtdalpha, dmm.rtdbeta, dmm.rtddelta, and dmm.rtdzero. Therefore, when both 3 and
4-wire RTDs are set to USER type for RTD, switching transducers between 3 and 4 will cause both
to use the same settings (for example, dmm.rtdalpha, dmm.rtdbeta). If unique settings are
needed, they must be changed, or use two different DMM configurations.
An error is generated if the value is out of range.
Example 1
dmm.func = "temperature"
dmm.transducer = dmm.TEMP_THREERTD
dmm.rtdalpha = 0.005
dmm.transducer = dmm.TEMP_FOURRTD
dmm.rtdalpha = 0.007
dmm.transducer = dmm.TEMP_THREERTD
print(dmm.rtdalpha)
Set an alpha constant for RTD to 0.005 for 3-wire RTD.
Change to 4-wire RTD and change the alpha constant to
0.007.
Switch back to 3-wire RTD. The value has been updated
to 0.007.
Output:
7.000000000e-03

Keithley 3721-ST Specifications

General

Brand	Keithley
Model	3721-ST
Category	Multimeter
Language	English