Carel ir33 Universale series User Manual page 36

ENG
6.5.5 Continuous compensation (parameter c19=4)
The compensation of St1 is active for values of B2 other than St2: with
this value of c19, parameter P2 can be used to defi ne a dead zone around
St2 in which compensation is not active, that is, when the value read by
B2 is between St2-P2 and St2+P2, compensation is disabled and St1 is
not changed:
if B2 is greater than (St2+P2), eff ective St1 = St1+ [B2-(St2+P2)]*c4
if B2 is between (St2-P2) and (St2+P2), eff ective St1 =St1
if B2 is less than (St2-P2), eff ective St1 = St1+ [B2-(St2-P2)]*c4
Compensation using c19=4 is the combined action of compensation in
cooling and compensation in heating, as described above. The following
diagrams show continuous compensation for positive and negative
values of c4. Neglecting the eff ect of P2, if c4 is positive St1 increases
when B2>St2 and decreases when B2<St2. Vice-versa, if c4 is negative St1
decreases when B2 > St2 and increases when B2 is below St2.
Key:
St1_comp
B2
c4
c22
c21
6.5.6 Enable logic on absolute set point & diff erential
set point (parameter c19=5,6)
When c19=5 the value read by probe B2 is used to enable control logic in
both direct and reverse mode.
If c19=6 the value considered is B2-B1.
Par. Description
c19 Operation of probe 2
5=enable logic on absolute set point
6=enable logic on diff erential set point
Validity: c0=1 or 2
c66 Enabling direct threshold
Validity: c0=1 or 2
c67 Enabling reverse threshold
Validity: c0=1 or 2
"Reverse" control with enabling of "direct" logic:
Looking at the example of a controller with two outputs, one of which
ON/OFF and the other 0 to 10 Vdc. When the temperature read by probe
B2, if c19=5, or the diff erence B2-B1, if c19=6, exceeds the threshold c66
(plus an hysteresis of 1.5°C to avoid swings), control is enabled on St1 and
P1; below this temperature, control is disabled.
OUT2
P1
ir33 universale +030220801 - rel. 1.0 - 16.04.2008
St1_comp
c22
B2
c21
P2 P2
c4>0
St1_comp
c22
B2
c21
P2 P2
c4<0
Eff ective set point 1
Outside probe
Authority
Maximum value of set point 1
Minimum value of set point 1
Def Min Max UoM
0 0 6
-50 -50 150 °C/°F
150 -50 150 °C/°F
OUT
OUT1
100%
0%
B1
St1
"Direct" control with enabling of "reverse" logic:
In this case too, a controller with two outputs, one of which a ON/OFF
and the other 0 to 10 Vdc. When the temperature read by probe B2, if
c19=5 or the diff erence B2-B1, if c19=6, falls below the threshold c67
(beyond an hysteresis of 1.5°C to avoid swings), control is enabled on St1
and P1; above this temperature, control is disabled.
-
6.5.7 Using the CONV0/10A0 module (accessory)
This module converts a 0 to 12 Vdc PWM signal for solid state relays to a linear
0 to 10 Vdc and 4 to 20 mA analogue signal.
Programming: to get the modulating output signal, the PWM control mode is
used (see the explanation for parameter c12). The PWM signal is reproduced
exactly as an analogue signal: the percentage ON time corresponds to the
percentage of the maximum output signal. The optional CONV0/10A0 module
integrates the signal provided by the controller: the cycle time (c12) must be
reduced to the minimum value available, that is, c12=0.2 s. As concerns the
control logic ("direct"=cooling, "reverse"=heating), the same observations
seen for PWM operation apply (see mode 4): the PWM activation logic is
faithfully reproduced as an analogue signal. If, on the other hand, a custom
confi guration is required, refer to the paragraphs on special operation ("type
of output", "activation", "diff erential/logic" parameters).
36
ABILITAZIONE/
ENABLE
ON
OFF
B2
c66 c66+1,5
OUT
OUT1 OUT2
100%
0%
B1
P1
St1
ABILITAZIONE/
ENABLE
ON
OFF
B2
c67-1,5 c67
C19=5
C19=5