Matching problem of solenoid hydraulic valves power supply

Some time ago, a client of mine encountered a problem that hydraulic YUKEN DSG-03 solenoid valve can not be opened.24V power supply to 9 solenoid valves by switching power supply,use collinear supply power to 9 solenoid hydraulic valves at the same time,and control signal to control the action of an hydraulic dsg solenoid valve.But why do often solenoid hydraulic valves can not move? What is the reason?

Through the specific communication, we learned that customer use the 1.5 party line length of 230 meters, so it is not difficult to understand why the solenoid hydraulic valve does not move.Because the power supply voltage selection of 24V, we need to consider the loss, if the cable is too thin and too much, loss will be too large. When the power supply to the YUKEN DSG-03 solenoid valve coil, the voltage is only 16V, has been lower than the normal open voltage of 20V, leading to the solenoid valve coil can not act. There are 9 solenoid hydraulic valve at the same time, so that the terminal voltage and power must be guaranteed to the solenoid hydraulic valves.