The MZ20A actuator stops controlling, and the Analogue Output remains at zero volts.
Satchwell Sigma, Field Devices
If the controller power and battery switches are switched off, then when the power is switched back on, the Analogue Output remains at zero volts.
To prevent is issue from occurring, it will be necessary to install a 2K2 ohm resistor between each channel and the common zero volt rail, as shown in the picture below.
Add the 2K2 Ohm resistors to the channels controlling the MZ20A actuators. These resistors do not need to be a close tolerance; a Carbon Film ¼ watt 5% is acceptable, (RS Stock No.135-881 or similar).
Note – The MZ20A, are the only actuators that we are aware of that require this modification, therefore if the actuator is changed to another type, the resistor should be removed again.