Application limits

Introduction

The IQ products CSV, CM-RC-01, CM-RC-02, CM-SW-01 and SE-i1 are featured by an application limit (= application envelope) protection function. It protects the compressor against excessive operating conditions, but allows also to receive warnings via Modbus when coming close to the individual limits. When taking the warnings into consideration, the superior system controller can take countermeasures and thus avoid a compressor stop.

Exemplary application limits with legend

Overview of relevant Modbus registers

Register	Name	Description	Type
12005 (I)	Envelope status	Status of the application limit 0 = Compressor stopped 1 = Compressor starting (application limit protection deactivated for 120 s) 2 = Compressor running within limit (within green dashed line) 3 = Compressor stopping (application limit protection deactivated) 4 = Application limit warning is active 5 = Application limit critical is active 6 = Application limit fault is active 7 = Defrosting mode is active	uint8
12006 (I)	Envelope zone	Zone in which the compressor is currently operating — or, if a fault is active, in which zone the operating point was when the fault was set. 0 = Inside application limit (within green dashed line) 1 = Low evaporation, low condensation 2 = Low evaporation 3 = Low evaporation, high condensation / high pressure 4 = High condensation / high pressure 5 = High evaporation, high condensation / high pressure 6 = High evaporation 7 = High evaporation, low condensation 8 = Low condensation	uint8

Application limit zonesSST: Saturated suction temperature = evaporating temperatureSDT: Saturated discharge temperature = condensing temperature — Application limit zones
SST: Saturated suction temperature = evaporating temperature
SDT: Saturated discharge temperature = condensing temperature