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T775U SERIES 2000 ELECTRONIC STAND-ALONE CONTROLLER
NOTES: (Integral Timing)
1. The Integral time is factory set for 400 seconds. This
is a good middle range and should satisfy many
applications. The integral time can be increased for
applications where sensed response is slow, and can
be decreased for applications where sensed
response is fast (e.g. discharge air control).
2. As a starting point, an optimal integral time for
discharge air typically ranges from 12 to 200
seconds. An optimal integral time for room control
typically ranges from 60 to 2,500 seconds. The
purpose of integral action is to reduce or eliminate
SETUP
OUTPUTS
MOD 1
DERIVATIV
Fig. 41. Setup - Outputs - Mod Out - Derivative.
SETUP
OUTPUTS
MOD 1
SCHEDULE
Fig. 42. Setup - Outputs - Mod Out - Schedule.
62-0255—09
SETUP
OUTPUTS
MOD 1
DERIVATIV
0
SEC
ENTER
DERIVATIVE
TIME FOR
MOD 1
M24603
SETUP
OUTPUTS
MOD 1
SCHEDULE
YES
NO
USE
SCHEDULE
FOR
OUTPUTS
M24604
20
the offset from setpoint during steady state control
that is often seen in proportional only control.
3. Keep in mind that control is most sensitive to
throttling range. Adjust the throttling range first before
any adjustment to integral time. Adjust throttling
range to be as wide as possible to start since this will
provide the most stable control. Remember that the
integral will eliminate the steady state error so you do
not need to have a small throttling range to have
accurate control. (Integral action allows for controlling
to a setpoint even with a wide throttling range).
1.3.1.4. DERIVATIVE
The Derivative default value is factory set to zero (no
derivative control). It is strongly recommended that the
derivative remain at zero (0) unless you have a very good
reason to adjust it. Derivative control is not needed in the
vast majority of HVAC applications.
1. From the Mod menu, use the p and q buttons to
highlight DERIVATIV.
2. Press the u button to display the Derivative sec-
onds.
3. Use the p and q buttons to increase/decrease the
value.
Default: 0 (zero)
Range: 0 to 3,600 seconds
4. Press the u button to accept the seconds and return
to the Mod menu.
1.3.1.5. SCHEDULE
The Schedule option displays only if the USE SCHED
parameter is set to Yes (see page 22).
1. From the Mod menu, use the p and q buttons to
highlight SCHEDULE.
2. Use the p and q buttons to highlight YES or NO.
Default: YES
3. Press the u button to accept the selection and
return to the Mod menu.
Each output can be set up to follow or ignore the built in
scheduler. To disable the scheduler for all outputs, see
"1.3.3.1. USE SCHED" on page 22.
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