Specifications

Reference Measurement Before Thermocouple Measurements

At this point, the concept of the VT1419A Scan List will be introduced. As each

algorithm is defined, the VT1419A places any reference to an analog input channel

into the Scan List. When algorithms are run, the scan list tells the VT1419A which

analog channels to scan during the Input Phase. Since the algorithm has no way to

specify that an input channel is a reference temperature channel, the command:

[SENSe:]REFerence:CHANnels (@<ref_chan>),(@<meas_ch_list>) is used to

place the <ref_chan> channel in the scan list before the related thermocouple

measuring channels. Now when analog channels are scanned, the VT1419A will

include the reference channel in the scan list and will scan it before the specified

thermocouples are scanned. The reference measurement will be stored in the

Reference Temperature Register. The reference temperature value is applied to the

thermocouple EU conversions for thermocouple channel measurements that follow.

A Complete Thermocouple Measurement Command Sequence

The command sequence performs these functions:

Configures reference temperature measurement on channel 15.

Configures thermocouple measurements on channels 16 through 23.

Instructs the VT1419A to add channel 15 to the Scan List and order

channels so channel 15 will be scanned before channels 16 through 23.

SENS:REF THER, 5000, (@115) 5k thermistor temperature for

channel 15

SENS:FUNC:TEMP TC,J,(@116:123) Type J thermocouple temperature

for channels 16 through 23

SENS:REF:CHAN (@115),(@116:123) configure reference channel to be

scanned before channels 16 - 23

Supplying a Fixed Reference Temperature

The [SENSe:]REFerence:TEMPerature <degrees_c> command immediately stores

the temperature of a controlled temperature reference junction panel in the

Reference Temperature Register. The value is applied to all subsequent

thermocouple channel measurements so there is no need to use

SENS:REF:CHANNELS when using SENS:REF:TEMP.

Programming the VT1419A Multifunction

Plus

Setting Up Analog Input and Output Channels

64 Chapter 3

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