{HEAD ~ A control unit} controls {TAIL ~ either the inflow liquid pump} only or both the inflow liquid pump and the outflow device depending on an inflow irrigation liquid pressure from a pressure sensor  
controls
{ HEAD ~ A control unit } controls { TAIL ~ either the inflow liquid pump } only or both the inflow liquid pump and the outflow device depending on an inflow irrigation liquid pressure from a pressure sensor
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH