Omron EJ1G, User Manual

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6
I/O Configuration and Main Functions
Section 1-2
EDU: End Unit
Note Auxiliary outputs are output via an internal bus.
1-2-2 What Is Gradient Temperature Control?
Gradient temperature control is a control method that achieves a uniform tem-
perature or preset temperature profile over a 2D surface. An example applica-
tion would be multi-point control of surface temperature using multiple
heaters. The gradient temperature control algorithm directly controls the aver-
age temperature of all points as well as the temperature difference between
each pair of points. The algorithm also includes methods to eliminate the
interference of each control output on the other control points.
When temperature inputs are received, the average temperature of all points
and the temperature differences between each pair of points are calculated.
PID control is performed for the present value (PV) of each of these control
points.
In addition, PID output values are distributed to prevent them from affecting
PID control performance at other points, thus eliminating interference. This
means that the interference of heaters on other control points is reduced to
enable uniform in-plane temperature control.
1-2-3 Main Unit Functions
Basic Units (TC4 and
TC2)
• Basic Units are used as the control I/O devices. (The HFU performs con-
trol processing.)
• There are two models of Basic Unit: The TC4 with four I/O channels and
the TC2 with two I/O channels.
• Universal input supports a thermocouple, platinum resistance thermome-
ter, or analog input.
• The type of input can be set separately for each channel.
• Control outputs are pulse voltage outputs.
Adjacent Unit
Port A communications
Port B communications
Auxiliary output 1 (See note.)
Auxiliary output 2 (See note.)
Gradient Temperature Control
Controls temperature
differences.
Controls average
temperature.
Suppresses interference of
control outputs on other points.