Refrigerant compressor

A method for monitoring a refrigerant compressor comprising a drive motor and

• a compressor unit which compresses a refrigerant entering through a suction inlet and allows it to exit through a pressure outlet, and a compressor monitoring system which is integrated into a compressor control system for the compressor, the compressor control system being part of the refrigerant compressor and determining a compressor condition by means of a first condition value that corresponds to a first saturation temperature in the suction inlet and a second condition value that corresponds to a second saturation temperature in the pressure outlet,
• said method comprising the following steps:
• presetting a deployment field of a deployment diagram, the deployment field incorporating the permissible compressor conditions in a compressor-specific manner, storing the preset deployment field in said compressor monitoring system of the compressor control system,
• determining the compressor condition by detecting the first condition value which corresponds to the first saturation temperature in the suction inlet and the second condition value which corresponds to the second saturation temperature in the pressure outlet,
• comparing the compressor condition with permissible compressor conditions lying in the stored deployment field of the deployment diagram,
• initiating a process of switching-off the refrigerant compressor if the compressor condition departs from the deployment field, the compressor monitoring system cooperating directly with a motor control system of the compressor control system for the purposes of switching-off the drive motor,
• determining the relative position of the determined compressor condition with reference to a deployment boundary enclosing the deployment field, and
• making available the information about the relative position of the compressor condition at a control interface for a higher-level control system of a refrigerant circulation system;
• wherein initiating the process of switching-off is a delayed switching-off process according to which the monitoring system determines a first time point at which the deployment boundary was overstepped, and if after a delay period the compressor condition is still outside the deployment field, the compressor monitoring system conveys a switch-off signal to the motor control system.