Operating Two Loops Of Control - Honeywell UDC3300 User Manual

Setpoint Rate/Ramp/Soak Program Operation
Viewing Each Loop's Process Variable
Regardless of which loop is being displayed, 1 or 2, the process variable of the non-
displayed loop can be shown in the lower display by repeated presses of the
LOWER DISPLAY key until 1PVXXXX or 2PVXXXX is displayed.
Internal Cascade Indication
When internal Cascade has been configured, an "I" will appear on the left side of the
upper display as long as Loop 1 is operating in the remote setpoint mode. Hold in
the SETPOINT SELECT key until RSP appears in the lower display then release the
key to select remote setpoint.
Switching between automatic and manual mode on either loop will not affect the
internal Cascade indication.

4.10 Operating Two Loops of Control

Operation of two individual loops of control is identical to operating a single loop of
control except that TUNING 2 group applies to Loop 2 only and two PID sets, 3 and
4, are available. TUNING group applies to Loop 1 with PID sets 1 and 2 applicable.
Operating Modes and Setpoint Source
The rules for Auto/Manual modes and changing setpoint sources are the same as
single loop operation.
Keyboard Operation
Note that the loop being displayed is the only loop affected by normal keyboard
operation. However, either loop can be reconfigured when in the Set Up mode
regardless of which is being displayed during normal operation.
Accutune
Two independent loops can be tuned at the same time, if configured. For Cascade
applications the secondary loop (Loop1) should be tuned first, then the primary loop
(Loop 2) should be tuned with Loop 1 in the Cascade Automatic Mode. For more
details on Accutune, see Section 4.15.
Setpoint Ramp or SP Programming
Either loop or both loops can be configured for a single setpoint ramp operation by
enabling the desired loop or loops (see Section 3 – Configuration).
An "H" for Hold or "R" for Run will appear when applicable in the left-most character
in the upper display, depending upon which loop is being displayed.
The RUN/HOLD operation is shown in Table 5-1.
Digital Inputs (Remote Mode Switching)
Digital Input 1 is dedicated to Loop 1 and Digital Input 2 is dedicated to Loop 2 when
two loops or Cascade control is configured. Otherwise, both DI's apply to single loop
configurations.
68 UDC3300 Expanded Model: DC330E User Manual 5/00