Table of Contents
Advertisement
AT
Autotuning: Autotuning is the automatic calculation
and entering of the control parameters (P, I and D) into
memory. The PXZ will autotune both reverse and direct
acting control applications. Autotuning will also auto-
matically set anti-reset wind-up (Ar). There are two
types of Autotuning that can be performed by the con-
troller, Autotuning at main setpoint or Autotuning at 10%
of full scale below main setpoint. Autotuning at 10% of
full scale below main setpoint may yield slightly differ-
ent values, not as precise, but the process overshoot
encountered during the autotuning procedure would
not be as great. Enter the value for the type of autotun-
ing you would like to run on your particular application
based on overshoot tolerances and the precision of the
PID parameters needed. For more information on princi-
ples of Autotuning, refer to Appendix A. See also page
9.
Setting:
0 - Autotuning off
1 - Autotuning performed at setpoint
2 - Autotuning performed at 10% of full scale
below setpoint
Standard type (AT=1)
Start of AT
End of AT
AT in operation
Set value (SV)
PV
(Measured value)
100%
ON
ON
OFF
OFF
0%
PID control
ON-OFF action
TC-2 Cycle Time (Output #2) The Cycle Time for output #2 is
that time where the output is on for a percentage of
that time and off for a percentage of that time, creating
a proportioning effect. Output #2 is the cooling side of a
heat/cool PXZ controller. A shorter cycle time provides
higher proportioning resolution and better control but
causes increased strain on the output device. Enter a
value that is based on the limitations of your con-
troller's output type.
Setting Range: 1 to 150 secs.
For relay output: Set to 30 secs or more
For SSR/SSC drive output: Set to 1 sec or more
For current output: Set to 0 (normally not indicated).
Not indicated without the control output #2 option.
CooL Proportional Band Coefficient for Cooling: The
Proportional Band Coefficient for Cooling is a multiplier
for the proportional band on the cooling side of a
heat/cool PXZ controller. It varies the width of the pro-
portional band on the cooling side. A large value would
establish a larger proportional band for more powerful
cooling loads. A small value would establish a smaller
proportional band for less powerful cooling loads.
Enter a value based on the power of your cooling load.
Setting Range: 0.0 to 100.0
Not indicated without control output #2 option.
Set to "0" for On/Off control.
Proportional Band
Prop. Band for Heating X Input Range =
Prop. Band for Cooling X Input Range =
Deadband/Overlap X Input Range
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
Low PV type (AT=2)
Start of AT
End of AT
AT in operation
Set value (SV)
PV
(Measured value)
100%
ON
ON
OFF
OFF
0%
PID control
ON-OFF action
2
X
2
=
X
200%
db
Deadband/Overlap: The Deadband/Overlap is that per-
centage of the heating side of the proportional band
where the heating (output #1) and the cooling (output
#2) outputs are separated by a Deadband or where
they Overlap on a heat/cool PXZ controller. A value
greater than zero establishes a Deadband or area
where neither the heating nor cooling outputs are
energized for more powerful heating and cooling loads.
A value less than zero establishes an Overlap or area
where both the heating and cooling outputs are ener-
gized at the same time for less powerful heating and
cooling loads. Enter a value based on the power of
your heating and cooling loads as well as the applica-
tion's efficiency in maintaining tight heat/cool control.
Setting range: -50.0 to 50.0% of the heating proportion-
al band.
Not indicated without control output #2 option
Deadband/Overlap
SV-10%FS
bAL
Balance: Balance is used to pre-position the propor-
tional band with respect to setpoint. With Balance (MV
Offset) set at 50% the proportional band will be cen-
tered around setpoint. To move the band left or right,
decrease or increase the balance setting respectively.
Setting range: 0-100%
Ar
Anti-Reset Wind-up: Anti-Reset is used to limit the
range where integration occurs. This helps in stabiliz-
ing a system. With Anti-Reset at 100%, integration will
occur throughout the proportional band. With Anti-
Reset set to 90%, integration will occur at 90% of the
band above the setpoint and 90% of the band below
the setpoint.
Autotuning automatically sets Ar.
Setting range: 0-100% of full scale, set in E.U.
11
# of units in the
Prop. Band for Heating X Input Range
= Proportional Band
for Heating
100%
# of units in the
Prop. Band for Cooling X Input Range
= Proportional Band
for Cooling
100%
# of units in the
Deadband/Overlap X Input Range
= Deadband/Overlap
100%
Input Range= (
minus
)
Heating Side
Coolng Side
100%
<1
OUTPUT
=1
0%
2
>1
Setpoint
TEMP
Coolng Side
Heating Side
100%
OUTPUT
Deadband
0%
Setpoint
TEMP
Heating Side
Coolng Side
100%
OUTPUT
Overlap
0%
Setpoint
TEMP
Hide quick links:
Advertisement
Table of Contents
