TAC 2112, Руководство пользователя, Страница: 39 / 70

TAC 2112, Manual Functional Description
TAC AB, 1999-08-01 0-004-7459-3 (GB), 7:7(
22
)
7.3.4 Automatic adjustment of the reset curve
In systems with reference sensors, the controller can adjust the reset
curve automatically. The temperature at the reference sensor is used
to continually carry out small corrections (±1
°
C) to the three points
(y0, y1 and y2) of the reset curves. After about a week, the reset curve
will have been adapted to suit the appropriate building.
Curve adjustment controller
The automatic curve adjustment is carried out by an I controller
(integrated controller), actual values and setpoints for the room being
used as input parameters. The following data apply for the controller:
I time: 1–720 minutes
Dead zone: 0,5
°
C
The I time corresponds to the time taken, in minutes, for the controller
to adjust the reset curve, at a constant control deviation of around 1
°
C
in the room.
Example: If the deviation is 2
°
C, the I time becomes 2 × 1 min., and
so forth.
Maximum curve adjustment
Adjustment of the reset curve has an adjustable limitation known as
Maximum curve adjustment . When the equipment is supplied, this is
set to ±5
°
C from the nominal curve. The nominal curve is the curve
from which the limitation is calculated.
Maximum
curve
Nominal curve
Adjusted curve
= permissible range for automatic curve adjustment
adjustment
Automatic adjustment of the reset curve
The nominal curve is determined by the fact that it takes on the values
of the adjusted curve. This takes place in the following cases:
•
When the controller is reset (all parameters resume their defaults).
•
Any curve point is adjusted manually.
•
The Maximum curve adjustment parameter is changed.