ICP DAS USA PMC series, User Manual

Page: 107 / 340

ICP DAS PMC/PMD Series User Manual
94
The IF Condition will use this already-adjusted value in the
evaluation operation, and the AI value retrieved from the “I/O
Information” page or Modbus Table via PMC-5151 would be the
adjusted value. The default value for MAX and MIN is 0, it
means the Scale function is disabled.

Deadband: In order to avoid signal oscillation that may result in
instability to the measurement of the AI channel value or system
operations, the user can set up a Deadband value for the AI
channel to reduce the oscillation effect to the channel value. The
detailed description of Deadband operation is as below:
There are three operation styles for AI Deadband. The AI Channel
setting in following examples is 0mA ~ 20mA.
(a) In the IF Condition, when AI > or >= a numerical value:
Assuming the Deadband value is set to be 2 mA, and the
following statements are defined in the related logic Rule: IF
AI>10mA, THEN DO=ON, ELSE DO=OFF, that means,
when AI receives a signal that exceed 10mA, the DO channel
will change to ON immediately, however, when the AI
channel value drops and becomes lower than 10mA, the DO
channel will not change back to OFF immediately until the
value reaches 8mA (10mA minus the Deadband value 2mA),
as shown in the following figure.
Figure7-22 : AI Deadband Operation(> or >= a numerical value)
(b) In the IF Condition, when AI < or <= a numerical value:
Assuming the Deadband value is set to be 2 mA, and the
following statements are defined in the related logic Rule: IF