4.4
MIR-491 cooling functions
With MIR-491, configuration parameter
CYCL
(
ConF
/
Cntr
/
CYCL
) can be
used for matching the cycle time of 2-point and 3-point controllers. This can be
done using the following 4 methods.
4.4.1
Standard (
CyCl
=
0
)
The adjusted cycle times
t1
and
t2
are valid for 50% or -50% correcting
variable. With very small or very high values, the effective cycle time is extended
to prevent unreasonably short on and off pulses. The shortest pulses result from
¼ x
t1
or ¼ x
t2
. The characteristic curve is also called “bath tub curve”
Parameters to be adjusted:
t1
: min. cycle time 1 (heating) [s]
(
PArA
/
Cntr
)
t2
: min. cycle time 2 (cooling) [s]
4.4.2
Water cooling linear (
CyCl
=
1
)
For heating (
Y1
), the standard method
(see chapter 4.4.1) is used. For
cooling (
Y2
), a special algorithm for
cooling with water is used. Generally,
cooling is enabled only at an
adjustable process temperature
(
E.H2O
), because low temperatures
prevent evaporation with related
cooling, whereby damage to the plant is avoided. The cooling pulse length is
adjustable using parameter
t.on
and is fixed for all output values.
Configuration level
MIR-491 cooling functions
40
Operating manual MIR-491
0,0
1,0
2,0
3,0
4,0
5,0
6,0
5
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95
Controller output [%]
relative
cycle
duration
T / T
1
t1
2 x
t1
3 x
t1
4 x
t1
-50% -67% -80% -100%
-30%
-20%
-10%
-6%
t.off
t.on
