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Control Functions
Note: The operating mode changeover can also happen while the machine is on. In
this case, the machine switches itself off complying with all its timings, then changes
mode and thereafter switches itself back on automatically.
Note: During the change, high and low temperature controls are enabled.
Note: Mode changing is disabled during defrosting cycles.
5.3 Setting the RTC
When the power supply is disconnected from the controller for a few days, the RTC
(Real Time Clock) system clock loses its time. When the controller power is
switched on again, you need to reset the RTC alarm (enabled by PA30 = 1). The
following page appears and allows you to set the time:
SET CLOCK DATE&TIME
17/06/2008 10:53:43
OK
After you configure the clock, press OK to update the RTC time. The main
application page is displayed. Press OK to confirm the resetting of clock alarm
(ERTC) at which point the conditions of the alarm has been restored.
If the alarm does not disappear, remove and reconnect the controller power, then
reset the alarm manually.
Note: This function is enabled only if the parameter PG04 = 1, that is, if the system
clock is enabled.
5.4 Compressor Control
The water temperature control (air-to-water or water-to-water machines) is carried
out through the control of mechanical components, that is, compressors and/or
fans. 2 types of controls are provided:
1. lateral-band control on entering chilled water temperature
2. zero energy band control on leaving chilled water temperature
5.4.1 Lateral-Band (LB) Control
Lateral-band is a proportional control function. The chilled water temperature is
controlled by switching the compressors on or off.
The following figure illustrates the behavior of lateral band control (Set point, Set
point + Proportional band) for summer operation (chiller). Depending on the chilled
water entering temperature, the number of compressors (steps) is either increased
or decreased. In this control mode, the entire band is shifted above the set point.
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S1A76018 03/2011