Specifications

For Thermocouples the <sub_type> parameter can specify CUSTom, E,

EEXT, J, K, N, R, S, T (CUSTom is pre-defined as Type K, no reference

junction compensation. EEXT is the type E for extended temperatures of

800 °C or above).

To set channels 24 through 31 to measure temperature using type E thermocouples:

SENS:FUNC:TEMP TC, E, (@124:131)

(see following section to configure a TC reference measurement)

Thermocouple Reference Temperature Compensation

The isothermal reference temperature is required for thermocouple temperature EU

conversions. The Reference Temperature Register must be loaded with the current

reference temperature before thermocouple channels are scanned. The Reference

Temperature Register can be loaded two ways:

4. By measuring the temperature of an isothermal reference junction during an

input scan.

5. By supplying a constant temperature value (that of a controlled temperature

reference junction) before a scan is started.

Setting up a Reference Temperature Measurement

This operation requires two commands, the [SENSe:]REFerence command and the

[SENSe:]REFerence:CHANnels command.

The [SENSe:]REFerence <type>, <sub_type>,[<range>,](@<ch_list>) command

links channels to the reference temperature EU conversion.

The <ch_list> parameter specifies the sense channel that is connected to the

reference temperature sensor.

The <type> parameter can specify THERmistor, RTD, or CUSTom. THER

and RTD, are resistance temperature measurements and use the on-board

122 µA current source for excitation. CUSTom is pre-defined as a Type E

thermocouple which has a thermally controlled ice point reference junction.

The <sub_type> parameter must specify:

–

For RTDs; “85" or ”92" (for 100 ohm RTDs with 0.00385 or 0.00392

ohms/ohm/°C temperature coefficients respectively)

–

For Thermistors; only “5000" (See previous note on page 61)

–

For CUSTom; only “1"

The optional <range> parameter can be used to choose a fixed A/D range.

When not specified (defaulted) or set to AUTO, the module uses

auto-range.

Programming the VT1419A Multifunction

Plus

Setting Up Analog Input and Output Channels

Chapter 3 63

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