R7426A,B,C,D TEMPERATURE AND UNIVERSAL INPUT CONTROLLERS
13 63-2565
Default Programming DefProg (C.23)
R7426D controllers also have the DefProg (C.23) parameter.
Setting DefProg to 1 resets parameter values to default (see
Tables 9 and 10 for default values). After default
programming, DefProg is reset to 0.
NOTE: A display of
def
indicates default programming.
Span Adjustment: UStartPoint/UendPoint (C.24/C.25)
I01 and I02 accept any analog inputs within the range of 0 to
10 Vdc. They also provide an input span adjustment to match
the connected transmitter range.
Input span start and end points can be adjusted with
UStartPoint and UendPoint. After adjustment, the span
converts to a 0 to 100 percent input range.
NOTE: UStartPoint and UEndPoint are common for both
inputs I01 and I02.
OffDelay for On/Off Output (C.26)
On/Off output is controlled by the Plant/System On/Off input. It
provides an Off switching output with adjustable delay time.
This can operate, for example, a fan for a certain time after
humidification ends.
Table 11. OffDelay.
StartTime (C.28)
The
StartTime
determines the time in the start-up routine
during which the W1 setpoint decreases from its temporary
value to the normal programmed value.
NOTE: This only operates with an OAT sensor connected
and the OAT is below 42°F.
Parameter Settings and Adjustment
High/Low Limit Setpoint: W
lim
(P.02)
For high or low limit control, parameter W
lim
is the setpoint.
During limit control, the throttling range Xp2 and reset time tr2
are active. Limit control is active only when I02 temperature
signal (I02ext is 0) is available, or sensor I01 (I02ext is 1) is
used for limit control.
For cascade control, limit setpoint W
lim
determines the
control point at which:
• Submaster setpoint (W
cas
) maintains the limit value.
• W
lim
is not shifted by the master control loop.
NOTE: High or low limit control is in accordance with the
configuration parameter LimTyp (C.13).
Compensation Changeover Point: W
comp
(P.03)
The parameter W
comp
defines the start point of summer or
winter compensation. Compensation is performed:
• Above W
comp
for summer compensation.
• Below W
comp
for winter compensation.
Summer/Winter Reset: Su/Wi (P.04/P.05)
Summer/Winter reset settings determine the compensation
sensor (I03) reset effect (I0Comp) on the main setpoint (W1).
To calculate winter and summer reset, throttling range must be
considered in proportional-only control (see Tables 12 and 13.)
NOTE: Compensation changeover (Xp) at +20°C OAT with
either P+I or P+I+D control is 0.
Table 12. R7426A,B,C Summer/Winter Reset Calculation.
Table 13. R7426D Summer/Winter Reset Calculation.
Reset Span Adjustment: R
cas
(P.07)
The reset span adjustment (R
cas
) determines the reset effect
in either degrees (R7426A,B,C) or percent (R7426D). If I01
(I01) deviates by 50 percent of the throttling range (Xp1), this
effect alters the submaster setpoint (W
cas
).
Throttling Range: Xp1/Xp2 (P.08/P09)
Throttling range (Xp) adjustment determines the change
required at the main sensor and limit or cascade sensor to
operate the output device through full stroke. Xp1 is the main
control loop throttling range. Xp2 is used when limitation or
cascade control (submaster control loop) are active (see
Table 14).
Input Function Switching Action Delay in min.
On Normal control Off to On 0
Off Output O1 is 0
percent
On to Off 0 to 60
Control
Schedule
Room
Temperature (I01)
OAT
(I03/I0comp)
Throttling
Range (XP)
Winter 68°F (20°C) 68°F (20°C) 3.6°F (2°C)
72°F (22°C) 5°F (-15°C)
Summer 68°F (20°C) 68°F (20°C) 3.6°F (2°C)
79°F (26°C) 95°F (35°C)
Control
Schedule
Humidity
(I01)
OAT
(I03/I0comp)
Throttling
Range (Xp)
Winter
(negative
reset)
50% rh 68°F (20°C) 5% rh
40% rh 5°F (-15°C)
Summer
(positive reset)
50% rh 68°F (20°C) 5% rh
60% rh 95°F (35°C)
AutWi
∆I01 Xp+
∆OAT
-------------------------
22 20–()2+
35
--------------------------------
0.12≅==
AutSu
∆I01 Xp–
∆OAT
-------------------------
26 20–()2–
15
-------------------------------
0.27≅==
--------------------------------
-------------------------------
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