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Programming the Outputs
control signal. If you need to switch from acid to
caustic on a pH control application or feed inhibitor
based on conductivity, you can reverse control using
these steps.
1- Press MENU
2- Scroll to the I/O Setup selection and press
OK
3- Scroll to select the relay desired and press
OK
4- Scroll to Control Action and press OK
Screen shows "ON decreases sensor" which
is normal for blowdown function as the
conductivity should decrease when the
blowdown valve is open.
5- To invert the output to "ON increases
sensor" press the SWITCH [F1] key,
then press OK.
Since the basic control has changed, the display
changes to the relay Adjust Set-points screen to
allow you to edit the new set-points. You will
notice that the On: and Off: values have been
reversed.
6- Use the ARROW and OTHER keys to
change the limit points if needed, then
press OK to accept and use these
values.
10.11 Special Control Functions:
Special controls are additional types of control
that improve on simple ON/OFF control. The
three general control modes have the following
special controls;
Feed Control Types: Time Cycling, Time
Modulate, and Proportional, Integral and
Derivative (PID) control.
Blowdown control Types: Captured Sample,
Varying Cycles.
Events-Other control Types: Prebleed Lockout,
Alarm output, Sensor wash
When using Timed Cycling, Time
Modulate or PID control, best results for
tuning the loop are achieved if you only
change one variable at a time and wait for
two or three cycles to observe the effect
of this change. This would include
changing the stroke % of the pump and
any setting in the special control program.
Page 76 of 102
SPECIAL CONTROL TIP:
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