21
5. If the cycle times of one or both outputs are long and the process
dynamic, there is a good chance that both outputs will be cycling
on and off at the same time around main setpoint. This is evident
if one or both outputs are relays.
6. Autotune is not effective on the cooling side of Heat/Cool control.
Autotune the controller for heat only and then manually tune the
cooling parameters.
Wiring and Setting
1. Make sure that your PXZ has the correct output type installed for
Output #2. Verify that the TC2, COOL, and DB parameters are indi-
cated in the primary (setpoint) menu.
2. Wire your cooling load to the Output #2 terminals located on the
back of your PXZ controller.
3. In the secondary (system) menu, program the correct code for
Heat/Cool action. See page 13 for the complete code table.
4. In the primary (setpoint) menu, program TC2, the cycle time for
Output #2. The table below is a general guide to TC2 settings.
5. Autotune or manually tune the PID parameters of your PXZ
controller. Autotune will work for the heating PID parameters
but not on the cooling parameters. You must manually tune the
cooling parameters.
6. With the heat side tuned, manually set the COOL parameter or
Proportional Band Coefficient for Cooling. If the cooling output is
less powerful than the heating output, the Cooling Proportional
Band must be narrower than the Heating Proportional Band; the
COOL parameter would be less than “1”. If the cooling output is
more powerful than the heating output, the Cooling Proportional
Band must be wider than the Heating Proportional Band; the COOL
parameter would be more than “1”. See the programming section
for more details.
7. Finally, you can add a Deadband/Overlap. The programmed
Deadband/Overlap parameter can be within -50% to +50% of the
Heating Proportional band. To establish a Deadband, parameter
“db” is set somewhere between 0% and 50% of the Heating
Proportional band. To establish an Overlap, db is set somewhere
between -50% and 0% of the Heating Proportional Band.
8. Manually fine-tune the parameters COOL and db until just the right
amount of cooling is achieved. Refer to the programming section
for more details on these parameters.
Heating Side Cooling SIde
Heating Proportional Band Cooling Proportional Band
[P/2] [P/2 COOL]
I I (same as for heating)
D D (same as for heating)
Relay 30
SSR Driver (pulsed DC) 2
4-20mA DC Not indicated or 0
Heating Side Cooling Side
Output#2 Type Setting(Secs)
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
To Next Page
Loading...
