Pump station automation with PLC
Pump stations are among the most common automation targets in Ukraine. Water supply, sewage, irrigation — all require pump control with pressure or level maintenance. A PLC replaces dozens of relays and timers with one compact device.
Over the past 3 years we have built about 40 pump stations using Delta DVP and Siemens S7-1200.
Basic architecture
| Component | Qty | Example |
|---|---|---|
| PLC | 1 | Delta DVP-SA2 / Siemens S7-1214C |
| VFD | 1-2 | Delta VFD-E 2.2-5.5 kW |
| Pressure sensor | 1-2 | 0-10 bar, 4-20 mA |
| Level sensor | 1-3 | Float or ultrasonic |
| HMI | 1 | Delta DOP-107 / Siemens KTP700 |
Algorithm: PID + cascade
Pressure sensor outputs 4-20 mA, PLC calculates PID and sends frequency to the first VFD.
- One pump insufficient → PLC starts second
- Pressure above setpoint → reduce frequency or stop extra pump
- Rotation — daily for even wear
Protections
- Dry run: level sensor or pressure relay
- Overload: current monitoring via VFD
- VFD fault: fault signal → stop + HMI alarm
- Flooding: float sensor in pump room
PLC selection
Delta DVP-SA2 ($150-200) + DVP-04AD ($80) or Siemens CPU 1212C ($250-350) + CM 1241.
Frequently Asked Questions
Which PLC for a borehole pump?
Delta DVP-SS2 + VFD for one pump. DVP-SA2 or S7-1212C for 2-3 pumps.
VFD needed for every pump?
No. One VFD for the lead pump, others direct-on-line via contactors.
Automation cost?
For 2 pumps at 2.2 kW: $800-1,500 with HMI.
Dry-run protection?
Float sensor ($20), pressure relay ($50), or current monitoring via Modbus (free).
Remote control?
Via Ethernet module or GSM modem — PLC sends data to SCADA or cloud.
Summary
Budget: Delta DVP-SA2 + VFD + sensor. Siemens level: S7-1200 + Sinamics + KTP700.
