17
14.SUCTION CONTROLS
In “selective mode” when only the main compressor output is activated, the controller assumes that the compressor operates at 100% of its capacity.
When the auxiliary output 2 is activated, the capacity is 66.6% and when the auxiliary output 2 is switched off and the auxiliary output 1 switched on the
capacity is 33.3% of the nominal capacity of the compressor.
14.3 Compressors with proportional modulation (frequency inverter):
Compressors with frequency inverter are controlled using an analog output (0-10 V). Only compressor 1 of each suction pressostat can be configured in
inverter mode (compressor modulation - parameter
1.2.x.22
). The compressor with frequency inverter will be the first to be activated and the last
to be deactivated.
An analog output is selected for the inverter (
1.2.x.34
) and a digital output can be defined for the Start-stop function of the frequency inverter. The
Start-stop output is configured as “Compressor 1 - Main Output” (
1.2.x.35
).
You can set the minimum (
1.10.x.1
), start (
1.10.x.2
), and maximum (
1.10.x.3
) values for the analog output.
14.4 Control modes:
Each suction pressostat can be programmed to operate according to one of the control modes in parameter
1.2.x.2
: Linear Mode, Rotation Mode,
Dead Band Mode, Dead Band Mode with Rotation, and Progressive Algorithm Mode.
14.4.1 Linear mode:
The linear mode is applied when using compressors with the same capacity, either combined or not with a proportionally modulated compressor
(inverter).
14.4.1.1 Linear mode associated with digital outputs only - compressors ON | OFF + Unloaders
When only digital outputs are associated to the Linear control mode, it commands the activation and deactivation of each compressor sequentially and
with pressure intervals of the same magnitude (step).
RCK-602
plus
uses a pressure setpoint and hysteresis value for compressor suction control. If
the compressors have unloader valves (auxiliary outputs), the drive logic is PPUU (Main first and then the unloader valves).
The digital outputs are associated with compressors in
RCK-602
plus
will set the activation and
Main Menu
1.Function setting
1.2 Suction
.
cc
-c
deactivation points according to the hysteresis value and the number of compressors configured in the suction, according to the “step” variable defined
below:
Example: Linear control associated with ON-OFF compressors only
ON | OFF compressors only
When using ON | OFF compressors, each compressor is associated with only one output so the Step is equal to hysteresis by dividing the number of
compressors.
1.2.x.2
Control mode: Linear
1.2.x.3
Setpoint: 25 psi
1.2.x.5
Digital hysteresis: 6 psi
1.2.x.15
Number of compressors: 6
1.2.x.22
Modulation of compressor 1: ON I OFF (0 I 100)
In this case each compressor is associated with one digital output and the Step is set to 6/6 = 1 psi.
Activation step of the digital outputs
Step =
Digital hysteresis
Number of outputs
Pressure Value for activating output “N”
Pressure Value for deactivating output “N”
Activation = Se (N x Step)
Activation = Se ((N-1) x Step)
25
26
27
28
29
30
31
(psi)
C1
C1 + C2
C1 + C2 + C3
C1 + C2 + C3 + C4
C1 + C2 + C3 + C4 + C5
C1 + C2 + C3 + C4 + C5 + C6
OFF
Outputs
1.2.x.23
Modulation of compressor 2 : ON I OFF (0 I 100)
1.2.x.24
Modulation of compressor 3: ON I OFF (0 I 100)
1.2.x.25
Modulation of compressor 4: ON I OFF (0 I 100)
1.2.x.26
Modulation of compressor 5: ON I OFF (0 I 100)
1.2.x.27
Modulation of compressor 6: ON I OFF (0 I 100)
