Danfoss VLT Series Operating Instructions Manual

Also see for VLT series: Service manual Installation guide Operating instructions Operating instructions Service manual

Danfoss VLT Series Operating Instructions Manual Manual pdf 13 page image

1.4.3 Master-Follower ConfigurationIn this configuration each pump is controlled by a frequency converter. All of the pumps and frequency converters must be of the same size. Staging andde-staging decisions are made based on the speed of the frequency converters. The constant pressure is controlled by the master drive operating inclosed loop. The speed will be the same in all running pumps with extended control. Up to 6 pumps can be controlled (with Advanced Control up to 8pumps).In the Master/Follower mode, MCO 101 supports up to 6 pumps - MCO 102 up to 8 pumps. Please seeMaster/Follower Operation Application for FC200 (Annex A) for further details.Illustration 1.8: ExampleFor this configuration relay selections in Group 27-7* “Connections” are as follows:27-70 RELAY 1 → [1] Drive 2 Enable27-71 RELAY 2 → [2] Drive 3 Enable27-72 RELAY 10→ [3] Drive 4 Enable27-73 RELAY 11→ [0] Standard Relay27-74 RELAY 12→ [0] Standard RelayThe master-follower configuration provides the gentlest transition from one stage to the next and the most energy efficient operation. For most installationsthe energy savings make this the most cost effective configuration.The system will automatically runtime balance all pumps depending on the pump prioritization made in par. 27-16. The Master/Follower system willprovide a certain level of redundancy. If the master drive trips, it will continue to control the follower drives.MCB-107 External 24 VDC power supply can be added to increase the level of redundancy.Furthermore it reduces wear and tear on pumps and motors. The relays set to [0] Std. Relay, can be used as general purpose relays, controlled by theparameters in group 5-4*.VLT® Operating Instructions1 Extended and Advanced Cascade ControllerOptionMI.38.C3.02 - VLT® is a registered Danfoss trademark 131