User`s manual

Using the Relay Multiplexer Modules 39Chapter 3
Measuring Temperature Using Thermocouples
(E1344A/47A Modules Only)
• Closing the AT and AT2 Tree Switches allows a multimeter connected
to the AT Tree Switch Terminals to measure the voltage of a
thermocouple or resistance of a thermistor connected to any channel.
• Closing the RT and AT2 Tree Switches allows a multimeter connected
to the AT Tree Switch Terminals to measure the resistance of the
thermistor on the terminal module.
• Use the thermistor resistance to calculate the temperature of the
terminal module to compensate thermocouple temperature
measurements (see “Comments” later in this section).
Example: Setup for
Measuring
Thermocouple
Temperature Using an
External Multimeter
Figure 3-6 and the following commands show how to set up channel 01 of a
single module switchbox to measure temperature of a thermocouple using
an external multimeter. Execute:
CLOS (@192,193)
192 and 193 close the AT2 and
RT tree switches.
measure thermistor temperature
Use multimeter.
OPEN (@193)
Opens the RT Tree Switch.
CLOS (@101,190)
Closes channel 01 and the AT
tree switch.
measure thermocouple voltage; calculate
compensated thermocouple voltage Use multimeter.
Figure 3-6. Temperature Measurement on Channel 01 Using a Thermocouple