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Chapter 7
535-PROF User's Manual
Applications
Hardware Configuration
•
Configure Unit 1 for a 4-20mA output (analog module for control).
•
Configure Unit 2 for the optional Remote Setpoint (see Chapter 4).
Software Configuration
1. For Unit #1
a. In
CONFIG.
menu, set
CTRL. TYPE
to STANDARD.
b. In
PV1 INPUT
menu, set the
PV1 TYPE
parameter.
If type is V/mA, set
LOW RANG
E and
HI RANGE
parameters to match
the transmitter range.
2. For Unit #2
a. Set the RSP input jumper in the
mA
position on the Microcontroller
Circuit Board (see Chapter 4).
b. Go to the
REM. SETPT
menu.
c. Set
RSP:LO. RNG.
to 0. Set
RSP:HI.RNG.
to 100. This will set the
range of the remote setpoint to 0 TO 100 (to correspond to the 0% to
100% output range of Unit #1).
d. Wire the control output of Unit #1 to the remote setpoint input of
Unit #2 as shown in
Figure 7.21.
e. When in operation, Unit #2 must be under remote setpoint control.
Tuning Cascade Control
1. The secondary loop is controlled by Unit #2, which does most of the work in
controlling the process. Put the secondary loop/Unit #2 under Manual con-
trol, and perform a Pretune on it. Once that Pretune is completed, put the
Unit #2 under Automatic control.
2. The primary loop is controlled by Unit #1, which controls disturbances or
load changes in the process. Now place the primary loop/Unit #1 into Manual
and perform a Pretune on this loop. Once this Pretune is complete, the
Cascade Control Loop is completely tuned. Place Unit #1 into Automatic
control to allow the system to control to the desired Setpoint of the Primary
loop.
