User Manual

Thermocouple Input Assembly (T3431)
PD - 6024 Mar - 06 3
Figure 1 . Block Diagram of the Thermocouple Input Assembly.
The Serial data received from the Mux is optically coupled at
the input m odule to provide electrical isolation. The input
module's 68000 - based microcomputer processes the
thermocouple data. This microcomputer’s functions include:
· Digital filtering
· Automatic calibration
· Cold junction compensation
· Temperature conversion and linearization
· Diagnostics
The processor modules send triplicated read data req uests to
the thermocouple input module over the I/O Safetybus. The
processors’ addressing data and data read requests are voted
by the module (preventing I/O Safetybus failures upstream
from the module from affecting module operations). The voted
result is then passed to the I/O bus interface logic.