Pixsys ATR 621 series, User Manual

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ATR 621 - User manual 25

=

Alarm1 selection (Cooling)

: Proportional band multiplier

: Overlapping / Dead band

: Cycle time Cooling
Parameter

(that ranges from 1.00 to 5.00) determinates the proportio-
nal band for cooling action, according to the formula:
- Proportional band for cooling action : =

*

In this way it is possible to have a proportional band for cooling action
that will be equal to heating proportional band if

= 1.00, or 5 times
greater if

= 5.00.
- Integral and Derivative time are the same for both actions.
Parameter

establishes the overlapping (in percentage) betwe-
en the two actions. For installations where heating and cooling outputs
cannot be activated at the same time, a Dead band will be confi gured
(

≤ 0), viceversa an overlapping will be confi gured (

> 0).
Figure below shows an example of double action PID (heating-cooling)
with

= 0 and

= 0.
SPV
PV
ATTIVO
ACTIVE
ATTIVO
ACTIVE

x

(COOL)

< 0

(HEAT)
COMMAND OUTPUT (HEAT)
ALARM OUTPUT (COOL)
SPV
PV
ATTIVO
ACTIVE
ATTIVO
ACTIVE

x

(COOL)

= 0

(HEAT)
COMMAND OUTPUT (HEAT)
ALARM OUTPUT (COOL)