To extend the number of sensors on the HMG 4000, the special CAN-based HCSI sensors were developed. The HCSI sensors, easily identified by their red type label, are automatically recognized along with all their characteristics by the HMG 4000. Up to 28 HCSI sensors can be connected to the HMG 4000 via the Y-distributor (available as an accessory) to set up an HMG-internal bus system.