PDS51 Series
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3.5.6 Well Low Level Probe Wiring
（
Optional
）
In order to avoid the water pump damage caused by dry running, you can connect a
water well probe to the DI2 & GND terminal of the PDS51 solar pump controller to detect
the level of the water well. The length of the water well probe line should not exceed 50m.
The probe shall give a close signal to connect DI2 and GND terminals together when water
level is too low. The well water level can also be detected through the software water
shortage detection function that comes with the controller.
3.5.7 Water Tank Float Switch Wiring
（
Optional
）
We recommend using a float switch to prevent the reservoir from overflowing, the
pump will stop when the reservoir is full. The pump will restart when it falls below the low
water level. It prevents overflow and reduces unnecessary pump wear. The solar water
pump PDS51 controller allows the use of small signal wires to connect a remote float switch,
even if the reservoir is located far away.
Stop Position
Startup
Position
Pumping
Range
Sealed Cable
Figure 3-5-4 Float Switch
Float switch requirements:
1. The minimum wire diameter is 1mm², and the longest distance can reach 50m.
2. If the application is used in long-distance transmission, a shielded wire needs to be used.
The shielding layer close to the controller end needs to be grounded
，
while the layer close to
float switch is not required to be grounded.
