Pixsys ATR244, Быстрый старт, Страница: 17 / 148

User manual - ATR244 - 17
8.9 Dual Action (Heating-Cooling)
ATR244 is suitable also for systems requiring a combined heating-cooling action.
The command output has to be configured as PID for Heating (Par. 38
ac.t.1
or Par. 57
ac.t.2
=
Heat
and
P.b. 1
or
P.b. 2
greater than 0), and one of the alarms (
AL.1.F.
,
AL.2.f.
,
AL.3.f.
,
AL.4.f.
,
AL.5.f.
or
AL.5.F.
) has to be
configured as
cooL.
The command output must be connected to the actuator responsible for heating, while the alarm will
control cooling action.
Parameters to be configured for the heating PID are:
ac.t.1
or
ac.t.2
=
Heat
Command output action type (Heating);
P.b. 1
or
p.b. 2
: Heating proportional band;
i.t. 1
or
i.t. 2
: Integral time of heating and cooling;
d.t. 1
or
d.t. 2
: Derivative time of heating and cooling;
c.t. 1
or
c.t. 2
: Heating time cycle.
Parameters to be configured for the cooling PID related to regulation loop 1 and alarm 1 are:
AL.1.F.
=
cooL.
Alarm 1 selection (Cooling);
p.b.m.1
: Proportional band multiplier;
o.d.b.1
: Overlapping / Dead band;
c.c.t.1
: Cooling time cycle.
Par.
p.b.m.1
(that renges from 1.00 to 5.00) determines the proportional band of
cooling action basing on the formula:
Proportional band for cooling action =
p.b. 1
x
p.b.m.1.
This gives a proportional band for cooling which will be the same as heating band if
p.b.m.1
= 1.00, or 5
times greater if
p.b.m.1
= 5.00.
Integral and derivative time are the same for both actions .
Par.
o.d.b.1
determines the percentage overlapping between the two actions. For systems in which
the heating output and cooling output must never be simultaneously active a Dead Band (
o.d.b.1
≤ 0),
must be configured, vice versa you can configure an overlapping (
o.d.b.1
> 0).
The following figure shows an example of dual action PID (heating-cooling) with
i.t. 1
= 0 e
d.t. 1
= 0.
1
ACTIVE
ACTIVE
SPV
PV

x

= COOL

x

= COOL

x

= COOL

< 0

=
0

> 0

( HEAT )

( HEAT )

( HEAT )
COMMAND OUTPUT ( HEAT )
ALARM OUTPUT ( COOL )
COMMAND OUTPUT ( HEAT )
ALARM OUTPUT (
COOL
)
COMMAND OUTPUT (
HEAT
)
ALARM OUTPUT ( COOL )
SPV
PV
ACTIVE
ACTIVE
SPV
PV
ACTIVE
ACTIVE
2
ACTIVE
ACTIVE
SPV
PV

x

= COOL

x

= COOL

x

= COOL

< 0

= 0

>
0

(
HEAT
)

( HEAT )

( HEAT )
COMMAND OUTPUT (
HEAT
)
ALARM OUTPUT ( COOL )
COMMAND OUTPUT ( HEAT )
ALARM OUTPUT ( COOL )
COMMAND OUTPUT ( HEAT )
ALARM OUTPUT (
COOL
)
SPV
PV
ACTIVE
ACTIVE
SPV
PV
ACTIVE
ACTIVE