Honeywell UDC2800 User Manual

190
Tuning indicators
A “T” will show under SP in the middle display until tuning is
completed.
Operation
The Accutune III algorithm provides user-friendly, on-demand tuning
in this controller. No knowledge of the process is required at start-
up. The operator simply initiates the tuning while in the automatic
mode.
Once Accutune III has been enabled in the TUNE setup group, either
“SLOW” or “FAST” tuning may be used. Which one is used is selected
via the lower display during normal operation.
For the SLOW selection, the controller calculates conservative tuning
constants with the objective of minimizing overshoot. If the
controller determines that the process has appreciable dead time, it
will automatically default to use Dahlin Tuning, which produces very
conservative tuning constants. The SLOW selection may be useful for
TPSC and Position Proportional applications, as it reduces “hunt”
problems for the motor. This selection is also recommended for
applications that have significant deadtimes.
For the FAST selection, the controller calculates aggressive tuning
constants with the objective of producing quarter damped response.
Depending upon the process, this selection will usually result in
some overshoot. For this reason, it may be desireable to enable the
FUZZY tune selection. See Fuzzy Overshoot Suppression for more
information. When Fuzzy tune is enabled, it will work to suppress or
eliminate any overshoot that may occur as a result of the calculated
tuning parameters as the PV approaches the setpoint. This selection
is best suited for processes with a single lag or for those that do not
have any appreciable deadtime. FUZZY tuning does not work well for
processes that have appreciable deadtime.
The Accutune III tuning process will cycle the controller’s output two
full cycles between the low and high output limits while allowing only
a very small Process Variable change above and below the SP during
each cycle. A “T” shows in the upper display until tuning is
completed.
Chapter 5 - Monitoring and Operating the Controller

Honeywell UDC2800 Specifications

General

Control Modes	PID, ON/OFF, Manual
Mounting	Panel Mount
Display	Dual 4-digit LED
Input Types	Thermocouple, RTD, mA, mV, V
Output Types	Relay
Power Supply	100-240 VAC, 50/60 Hz
Communication	RS-485 Modbus RTU
Enclosure Rating	NEMA 4X