H&L Local Pressure Protection - Mitsubishi Electric Evolution+ s-MEXT Technical Manual

17.11 H&L Local Pressure Protection
This function, available for all units in the same group and with APL function enabled, permits monitoring the formation of High
Pressure Spots and Low Pressure Spots in a room controlled by various units on the LAN network.
INFORMATION:
The function can be viewed only after enabling the LAN network and the Active Pressure Load
function.
The parameters for setting and enabling this function can be modified only by the Priority unit.
The protection is enabled when the differential pressure read by the local probe of each unit is not too high or too low, according
to the following criteria:
•
High pressure Spot protection:
•
Low pressure Spot protection:
When the function is activated as a result of one the above limits being reached for a time greater than P26.24, it "frees" the
protected unit from having to adjust according to the average pressure, so that it can adjust according to the pressure read by
its own probe, and the pressure fault detected in that individual unit can be managed independently.
After the local differential pressure detected by the "freed" unit has been within the limit of the High pressure Spot and Low
pressure Spot for a time greater than P26.23, the unit is reconnected to the LAN and made to adjust according to the average
pressure.
INFORMATION:
The units are included in the average calculation even if in high or low pressure protection.
The diagram below represents the operating mode described above
Pressure
Local P
Adjustment pressure
Local P
Average P
Version 38
���������� ������������������������ ���������������� > �������������� ������������������������ ���������������� + ��26.21(10����)
���������� ������������������������ ���������������� < �������������� ������������������������ ���������������� − ��26.22(10����)
Pr otection Off and exit of the
P.Average adjustment
Time O n
Figure 17-14: example of operation of the H&L Local Pressure Protection.
Protection Off and return to the
P.Average adjustment
High pressure Spot
Low pressure Spot
Time Off
High Band
Average P
Low Band
Time
Time
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