[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction:TYPE
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction:TYPE
Syntax
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction:TYPE <type>[,(@<ch_list>)]
[SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction:TYPE? [(@<ch_list>)]
Description
Thermocouple measurements require a reference junction temperature. For the reference junction temperature, you can use an internal measurement on the module's terminal block, an external thermistor or RTD measurement, or a known fixed junction temperature. This command selects the reference junction source for thermocouple measurements on the specified channels.
Used With:
- 34901A 20 Channel Multiplexer (2/4-wire) Module
- 34902A 16 Channel Multiplexer (2/4-wire) Module
- 34908A 40 Channel Single-Ended Multiplexer Module (RTD only; not FRTD)
Parameters
Name Type Range of Values Default Value <type> Discrete {INTernal|EXTernal|FIXed} This is a required parameter. <ch_list> Channel List One or more channels, as shown:
(@310) - channel 10 on the module in slot 300.
(@305:310) - channels 05 through 10 on the module in slot 300.
(@202:207,209,302:308) - channels 02 through 07 and 09 on the module in slot 200 and channels 02 through 08 on the module in slot 300.
If you omit the optional <ch_list> parameter, this command applies to the currently defined scan list.
Remarks
- The accuracy of the measurement is highly dependent upon the thermocouple connections and the type of reference junction used. Use a fixed temperature reference for the highest accuracy measurements (you must maintain the known junction temperature). The internal isothermal block reference requires no external wiring but provides lower accuracy measurements than a fixed reference.
- To store a reference temperature, first configure channel 1 on a multiplexer card for an RTD or thermistor measurement (see CONFigure:TEMPerature command). Then assign the measurement from that channel as the external reference using one of the following commands:
[SENSe:]TEMPerature:TRANsducer:FRTD:REFerence
[SENSe:]TEMPerature:TRANsducer:RTD:REFerence - When you initiate a measurement on an external reference channel (see INITiate or READ? command), subsequent thermocouple measurements use the stored temperature as their reference. The temperature is used for all subsequent thermocouple measurements on that card.
- If you select a fixed reference junction source, you can specify a value between -20 °C and +80 °C using the [SENSe:]TEMPerature:TRANsducer:TCouple:RJUNction command. You must always specify the temperature in degrees Celsius regardless of the temperature units currently selected (see UNIT:TEMPerature command).
- The instrument selects the fixed source after a Factory Reset (*RST command). An Instrument Preset (SYSTem:PRESet command) or Card Reset (SYSTem:CPON command) does not change the setting.
Return Format
The query returns INT, EXT or FIX for each channel in the <chan_list>. Multiple channels are separated by commas.
Examples
The following command sets the reference junction type to an external thermistor on channels 01 through 04 in slot 200.
TEMP:TRAN:TC:RJUN:TYPE EXT,(@201:204)
The following query returns the reference junction type for the four channels shown.
TEMP:TRAN:TC:RJUN:TYPE? (@201:204)
Typical Response: EXT,EXT,EXT,EXT