Watson-Marlow qdos H-FLO Reference Manual page 115

14.4.6 Control Settings>Floating ground
A single 4-20 mA signal could be connected to two or more pumps in series. This would allow
both pumps to be controlled through one input signal whereby, if either of the pumps fails or is
powered off, then another pump would receive the control signal.
Toggle
Enabled
Disabled
Contact your local Watson-Marlow representative if more information is required.
Action
Floating ground
Grounded at pump
115