Evco c-pro nano RACK User Manual download pdf (Page 50)

C-PRO NANO RACK E C-PRO MICRO RACK APPLICATION MANUAL

Page 50

As we can see from the figure, the adjustment foresees the setting of certain timings within which, depending

on the zone, the turn-on and shutdown requests for the various steps must be adjusted to work according to

established time intervals.

Based on the difference between the actual suction pressure value and the reference value, the times will vary

proportionally according to the values set. The reference value mentioned represents, according to the case, the

right and left limit of the neutral zone with the addition of another differential (which can be set through a

parameter) within which the proportional variation of the time in question will be found.

At the limits of the adjustment, the values of the turn-on and shutdown times are the maximum and minimum

times that are established by the parameter. To render the request time constant during the turn-on phase, it is

enough to set the NZ TOnMin and the NZ TOnMaz parameters to the same value. The same thing is true for the

shutdown phase.

6.3.3 Sideband adjustment with inverter

This check adds an inverter adjustment to the normal sideband adjustment; in order to do this, it is necessary to

set some parameters relative to the inverter device that is to be used, besides enabling its use.

The parameters relative to the first circuit are the following:

- SPC1 = Setpoint compressors (SP)

- PC14 = Type of adjustment = 0

- PG12 = Activation of the inverter

- PC24 = Inverter differential (DI)

- PC25 = Inverter offset with respect to the suction setPoint (OFSI)

- PC26 = Minimum value of inverter (MinI)

- PC27 = SpeedUp Time

Based on the measured value from the suction probe, the output of the regulator will assume different values.

If the value measures with the probe is less than or equal to the SP + OFSI value, the output of the regulator

assumes the value 0.

If the value measured with the probe is between the SP + OFSI value and the SP + OFSI + DI, the output of the

regulator will assume a value which is proportional to the value of the suction probe.

If the suction probe assumes a value which is higher than or equal to the SP + OFSI + DI value, the output of

the inverter will assume maximum value.

If the MinI parameter has been set, at every turn-on the inverter will maintain that value as a starting value.

If the parameter for the speedUp time has been set, at every breakaway point the inverter will assume maximum

value for the seconds described by this parameter.

The range of values that the inverter output can assume lies between 0 and 100 percentage points, with two

decimal numbers.

SP + OFSI SP + OFSI + DI

Pressure

Inverter

MinI

100.00 %

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Evco c-pro nano RACK User Manual Page 50