Dwyer 32DZ - Manual (Page 13)

June, 2000 Page 13 of 40 949-1318
The calculations for the PID values are the same as used in the standard Ziegler
- Nichols equations that have been recognized as standard for decades.
The only modification to the application of the Ziegler - Nichols equations is
controlled by the
dFC1 dFC1 dFC1 dFC1 dFC1 and dfC2 dfC2 dfC2 dfC2 dfC2 menu items. These menu items control the
amount of rate (derivative) that is applied. A dFC1 dFC1 dFC1 dFC1 dFC1 or dfC2 dfC2 dfC2 dfC2 dfC2 setting of 3 33 33 (factory
default) or less allows for less damping. A dFC1 dFC1 dFC1 dFC1 dFC1 or dfC2 dfC2 dfC2 dfC2 dfC2 setting of 4 44 44 allows
for critical damping as set forth in Ziegler - Nichols. A dFC1 dFC1 dFC1 dFC1 dFC1 or dfC2 dfC2 dfC2 dfC2 dfC2 setting
of 5 55 55 or more allows over damping of the process.
Program Setup and Operation
In the secondary menu set tun1 tun1 tun1 tun1 tun1 or tun2 tun2 tun2 tun2 tun2 to SELF SELF SELF SELF SELF . Skip Lrn1 Lrn1 Lrn1 Lrn1 Lrn1 / Lrn2 Lrn2 Lrn2 Lrn2 Lrn2 and check
to make sure that dFC1 dFC1 dFC1 dFC1 dFC1 / dfC2 dfC2 dfC2 dfC2 dfC2 is (are) set to the desired value. Back up to
Lrn1 Lrn1 Lrn1 Lrn1 Lrn1 / lrn2 lrn2 lrn2 lrn2 lrn2 and set to YES YES YES YES YES . The control will begin the Self Tune function.
While the Self Tune function is active, the right hand decimal point on the
lower display will blink. When Self Tune is complete, the blinking will stop.
After Self Tune is complete, the tun1 tun1 tun1 tun1 tun1 / tun2 tun2 tun2 tun2 tun2 setting(s) automatically
switch(es) to PID PID PID PID PID . This allows examination and / or modification of the
values calculated. We recommend that you do not change the calculated
values unless you have a firm understanding of the parameters involved and
their function. For more information on PID tuning, please contact your
supplier.
OPERATION AND PROGRAMMING OF OPTIONS
Option 992, Serial Communication.
The serial communications option allows the control to be written to and read
from a remote computer or other similar digital device. Communication is
allowed through a RS-485 (Option 992) port.
See Wiring for Optional Inputs and Outputs for information on wiring the
communication lines. Wiring for the RS-485 is run from control to control in
a daisy chain fashion with a termination resistor (120 ohms) across the
transmit and receive terminals of the last control in the chain.
Select the control address and communication baud rate with the Addr Addr Addr Addr Addr and
bAUd bAUd bAUd bAUd bAUd menu items in the Secure Menu. The address for Zone 1 will be the
address selected. The address for Zone 2 will be the address selected for Zone
1 plus one. For example, if
Addr Addr Addr Addr Addr is set to 1E , Zone 1 parameters will be
addressed through address 1E and Zone 2 parameters will be addressed
through address 1F .