Long distance pump control

[Electromatic]

I've been asked to help reconfigure a municipal water pump booster station. There is a pressure tank about 2,000ft from the pumps. The water (not electrical) engineer wants a simple pressure switch at the tank to tell the pumps to turn on or off.
What are the difficulties with using a dry contact at this distance?
Alternatively, we could use a pressure/level transducer and a 4-20mA signal. I understand the theory of loop impedance limitations, but I've never had to completely design a transmitter, sensor, cable system. What do I need to look out for at this distance--or would most equipment be fine?

TIA

 

[electrofelon]

i would just use the pressure switch to control a contactor.

 

[ptonsparky]

I've never used a dry contact at that distance.
A two wire control may hold in due to capacitance, IIRC. Adding load at the coil end helps or use three wire and add a load directly at the pressure switch

 

[ptonsparky]

It's been awhile. DC seemed to work.

 

[ptonsparky]

Radio would be the next.
I have a spare that reaches 1.5 mile .

 

[Electromatic]

Would a 4-20mA signal with shielded, twisted pair be feasible? Would I have to be extra careful in selecting a sensor and input based on impedance? We wouldn't need a true analog signal--we could just set low and high mA values as on and off.

 

[hillbilly1]

I’ve done one using a 120.volt cube relay controlled by a level sensor at a water tower about a quarter of a mile away. Very little voltage drop because of the low current of the cube relay. It in turned controlled the starters for the pumps. Same could be done with the pressure switch. Kinda old school though, most nowadays use variable speed pumps for better pressure control.

 

[don_resqcapt19]

Would a 4-20mA signal with shielded, twisted pair be feasible? Would I have to be extra careful in selecting a sensor and input based on impedance? We wouldn't need a true analog signal--we could just set low and high mA values as on and off.

I have done industrial 4-20 mA instruments loops that were that long without issues. Most of the ones I worked with were limited to 750Ω, with the PLC input having 250Ω, leaving 500Ω for the wiring.