KGL Operating Manual – VS 3010 BS
2018-07-02
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4.4.8.4 to-Z1 setpoint shift with cascade regulation
The t0_Z1 setpoint is shifted within the range ”to-min. Z1” and ”to-max. Z1” (parameter to-Min. Z1, to-Max. Z1
menus 3-2-1-5 / 3-2-1-6) If cascade regulation is active, the to-Z1 setpoint shift can be overridden if the tc-Z2
actual value is too high. With the parameter ”Begr. to-Sch.” It can be determined whether the to-Z1 setpoint
shift is to be influenced via the tc-Z2 actual value. The function is only active when the cascade controller and
the HP-Z2 transducer are active and there is no fault in the HP-Z2 measuring circuit.
While to-Z2 is lower than ”tc Comp. ON Z2” (see also 2. HP Monitoring), a t0-Z1 setpoint shift in the existing
form is performed. If tc Z2 is greater than the threshold ”tc Comp. ON Z2”, the to-Z1 setpoint will no longer be
increased. It is maintained at the calculated to-setpoint when “tc Comp. ON Z2” has been reached. However a
reduction remains possible.
tc-Z2 exceeds the threshold: tc_Grenz = (tc Comp. OFF Z2 - tc Comp. ON Z2) / 2
Menu 3-3:
tc Comp. OFF Z2: Parameter ”tc Comp. OFF Z2”
tc Comp. ON Z2: Parameter ”tc Comp. ON Z2"
The to-setpoint can be reduced to the level ”to-Min Z1”.
4.4.9 Load shedding
For example, in order to prevent a set energy consumption being exceeded, it may be necessary to initiate a
forced shutdown of consumers. The pack controller is equipped with 2 digital inputs for the load shedding of
the Z1 compressors (terminals 82/83 and 84/85) and 1 digital input (terminals 86/87) for the load shedding of
the Z2 compressors. Accordingly, in the Z1 temperature range a maximum of 2 and in the Z2 circuit a
maximum of 1 compressor can be disabled via load shedding.
Z2 load shedding is only possible when the Z2 compressor is controlled via the suction gas pressure. The
compressors are switched off immediately.
One compressor per load shedding input is unloaded for single-stage compressors. In the case of capacity-
controlled compressors, one compressor capacity stage is switched off per load shedding input as default
(parameter CompOFF.w.LdSh Z1/Z2 set to “N”). If a capacity-controlled compressor should be completely
unloaded via a load shedding input, the parameter CompOFF.w.LdSh Z1/Z2 (menu 3-1) must be set to “Y”.
The respective Z1/Z2 parameter is only displayed for capacity-controlled compressors in Z1/Z2.
Independent of the load shedding signals, a minimum refrigeration capacity in both the Z2 and Z1 temperature
