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Version 2.02 15.05.2007
Function of VS 3000
34
The run-up speed curve for a system equipped with five fans is illustrated in the following diagram
ZNR.
51203
74
530
E0
t
Speed [%]
100%
Speed
maximum
+ 50%
Speed
minimum
Enabling speed adjuster S1 ON
S2 ON
S3 ON
S4 ON
S5 ON
Start delay
Fan stage
50 %
Operation by power supply S6 ON
Control signal [%] =
(Speed
+ 50%) * (No.RunningStages-1)
(
)
No.RunningStages
min
With a negative control error, all running fans are reduced to minimum speed +20%. If pressure remains below
the setpoint, fan stages are unloaded with the set time delay. Switching from fixed-speed mode back to variable-
speed mode is not made until pressure drops below the tc setpoint. Finally the speed adjuster is disabled
through the first fan output S1 of the VS 3000 when speed drops to 0.
If a minimum speed greater than 0 has been entered for the speed adjuster in the
Min. Speed paramete
r (Menu
3-2-2-1), speed is ramped down to 0 after a definable time (
Basic Time OFF F1
parameter, Menu 3-2-2-2-c) and
fan output S1 is switched off.
Enabling fan stages (Parameter ENAB.COND., Screen 3-1-e)
Enabling of fan stages is directly allocated to the fan relays. Accordingly the speed adjuster and connected fans
can be disabled by disabling Fan Stage 1. When the first stage is disabled, HP control works as a step controller
with stages 2 to n-1.
The maximum number of stages that can be disabled or enabled is as follows:
- VS 3000 basic configuration:
3 fan stages
- One SIOX extension module added:
7 fan stages
- Two SIOX extension modules added:
11 fan stages
The stage
No. Cond.Stages
+ 1 for fixed-speed operation cannot be programmed. It is not shown on the AL 300
Operator Terminal, CI 3000 Store Computer or in the LDSWin PC software.