Rockwell Automation 1771-TCM,D17716.5.108 TEMPERATURE CONTROL MOD - Manual (Page 10)

Introduction to the Temperature Control Module
Chapter 1
1-2
The control-variable output of each loop is sent from the 1771-TCM
module to the PLC data table as a numeric value. The ladder logic can
monitor this numeric value as well as send it to an analog output module to
generate the control variable output signal to the temperature control
actuator.
The control-variable output of each loop is also sent from the 1771-TCM
module to the PLC data table as the duty cycle of a bit that is cycled at a
regular period. We call this bit a time-proportioned output (TPO) bit. The
ladder logic can send this signal to a digital output module to generate the
control variable output signal to the temperature control actuator.
X
Y
On
Off
Duty Cycle = Ċ
X
Y
TPO Bit
The 1771-TCM module provides:
8 PID loops
auto-tuning of PID loops
a thermocouple input (+100mV) for each PID loop
16-bit analog-to-digital converter resolution
a heat signal (for each PID loop) to the data table as a numeric value
a cool signal (for each PID loop) to the data table as a numeric value
a heat signal (for each PID loop) to the data table as a TPO bit
a cool signal (for each PID loop) to the data table as a TPO bit
temperature values in
C or F
self-calibration (external reference required)
software
configuration
user-selectable high and low alarms with dead band for hysteresis
self
diagnostics
input open-circuit detection
Features of the Temperature
Control Module