HE693THM665  Isolated Thermocouple Module

The Isolated Thermocouple Input Modules allow thermocouple temperature sensors to be directly
connected to the PC without external signal processing (transducers, transmitters, etc.). All analog and
digital processing of the thermocouple signal is performed by the module. These backplane-isolated (or
bus-isolated) modules report temperature values to the PLC I/O table in increments of 0.5°C, 0.5°F,
0.1°C, or 0.1°F respectively. The module features six thermocouple channels whose temperature values
are reported to 6 %AI input registers. Each channel can be individually configured for a specific type of
sensor wire. There are 6 %I alarm bits and one setpoint alarm for each channel. (The HE693THM667
has 12 alarm bits and two setpoints per channel.) Alarm setpoints are configured for each channel using
6 %AQ registers. An available feature on the isolated thermocouples is the use of external AD592 cold
junction compensation. This allows cold junction compensation to be accomplished in a remote
isothermal terminal strip with standard copper wire run from the remote terminal strip to the module.
There are four versions of the Horner APG Isolated Thermocouple Input Module: HE693THM668,
HE693THM667, HE693THM666 and HE693THM665. The HE693THM668 is a six-channel module with
+/-1500V AC isolation to the PLC backplane and +/-250V AC isolation channel-to-channel. The
HE693THM667 is similar to the HE693THM668 except that the HE693THM667 has 2 setpoints per
channel. The HE693THM666 is equivalent to the HE693THM668 with the addition of a 60Hz notch filter.
The HE693THM665 is also equivalent to the HE693THM668 with addition of a 50Hz notch filter. The
purpose of these filters is to eliminate noise generated by power lines in the United States (60Hz) and
Europe (50 Hz).