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PLC Pump Control

PROJECT: Off Grid Pumping Station


Design and build two pump  control panels  to control the  potable rain water supply,  and provide  a reliable grey water recycling  and dosing  system for the w.c cisterns along with the ability to redistribute  all excess grey water to a remote off the grid irrigation pump station with holding tanks.


The remote irrigation control panel  and pumps would need to distribute the  excess stored  water periodically  to the irrigation  gardens or to the  greenhouses.  The ability to  wirelessly  communicate  between  the master control panel/pump  station and irrigation control panel/pump  station is  essential to  maintain a  control  loop and  to receive trending and alarms.  Trending  on all tank  levels,  tank  temperatures,  pump run times and events and alarms logging was required.

Grey Water Lift Pump + Rain Water Circulation Pump


We designed and built two individual control panels. The master control panel would automate the primary pumps. First, we designed a simple "independent"  PLC control system  using  a  Zelio  PLC  smart  relay  controller  to monitor the rain tank water level  and  temperature. The  rain  tank  circulation  pump  automation is controlled  by a tank  level pressure transducer and pump pressure transducer respectively. End user rain water demand would operate on pump pressure when a tap is opened.


The next step was to install and program an additional Zelio PLC smart relay  controller in the same control panel for the grey water system. Again, we used the basis of this rain tank/pump program for a second simple  "independent" control system to monitor and automate the grey tank lift  pump for w.c cistern water demand and high level water diversion. We added PLC logic  for  the w.c cistern dosing. The grey water level is maintained by an ultrasonic level sensor at <65%. Water above  this level will trigger the grey water irrigation valve to open and diverts the excess grey water to the remote irrigation holding tanks and pumping station.


We designed and automated a simple filter backwash  cycle followed by a grey pump suction line purge to be performed at the end of every grey pump off cycle. This was done by  momentarily changing the VSD speed from 50Hz to 60Hz to maximize stored water pressure in the pressure tank, post pump cycle, in anticipation of the imminent  backwash cycle. This was able to provide an extra 20% pressure gain resulting in 85-90 psi for  the backwash water pressure. This pressure is dissipated within 5 seconds, through the filter and is necessary to perform the filter backwash thoroughly. The pressure drops post backwash to  22 psi at idle, so risks of leaks are very low. The backwash system has extended the filter maintenance schedules significantly to provide a reliable grey water system.


We designed and built a second control panel for the remote irrigation pump and tank automation. We wrote a dedicated program  for a third simple Zelio "smart relay" PLC  controller to automate the off the grid irrigation pumps on timed outputs throughout daylight hours. A diversion valve was added to alternate (or divert excess)  irrigation tank water to the greenhouse/gardens.


All  independent PLC systems were programmed to monitor water levels and temperature, low tank alarms and inline flow switches were incorporated to prohibit pumps running dry. Low pump pressure PLC logic was added to the programming as a precaution for the pumps.

All three independent  PLC's were networked back using Modbus serial RTU to a master PLC with a custom HMI solely for monitoring, secondary control and alarms and events trending. We configured a wireless  transceiver RF (radio frequency) modbus RTU   network for the  irrigation pump station for remote local PLC network communication. Global monitoring and control is achieved from the ethernet network port on the HMI to the world wide web via a smart phone/device.

ZELIO Smart Relay PLC and MODICON PLC Pump Automation and contol

Master   Grey  Lift Pump   and  Rain  Circulation Pump  control panel with two Schneider  Zelio PLC controllers, automating two pump VSD's.  The  Schneider  Modicon M221 Master PLC is networked back to a local HMI panel. The HMI has  a  VPN  ethernet  TCP/IP  communication connection for internet remote access, and end user monitoring and control.

IRRIGATION Water Pump solar Zelio Smart Relay PLC controller

12VDC Solar off the Grid Irrigation  pump control panel with a Schneider Zelio PLC  and wireless RF Modbus transceiver Modbus communication

Schneider Zelio HMI Smart Phone duplication of  Harmony Pump Monitoring and Trending for Tank Level and Pump Pressure

HMI  - Smart Phone duplication of our Harmony HMI Irrigation pump and water tank monitoring

HMI Smart Phone Monitoring of Grey Water Tank Level, water temperature and Pump Pressure

HMI  -Smart Phone HMI monitoring of our  Grey Water Pump and Tank displaying a filter backwash .

Schneider Harmony HMISTU-855 HMI Screen Controller

Rain   Water   Circulation   Pump   +  Tank  Level monitoring  and  control  using  a  Zelio  smart  relay PLC  and  HMI.

Monitoring and trending of water tank level, pump pressure and temperature.

Grey  Water   Pump  +  Tank   Level   monitoring and control using Zelio smart relay PLC / HMI. 

Pump pressure monitoring, water tank level trending and diagnostics. Schneider Zelio and Schneider Modicon PLC automation

Irrigation  Water Pump + Tank Level HMI monitoring using  Zelio  PLC  and  RF  radio  frequency  modbus transceivers  for  wireless  communication  back to the Modicon M221 master PLC controller.


Schneider Zelio SR3B101BD PLC modules for the pump stations control and automation.

Schneider Modicon M221 PLC as the master controller to communicate between all three Zelio PLC's.

Schneider HMISTU-655 Magelis HMI for the monitoring, control, trending and remote ethernet access.

Ebyte Modbus RTU wireless 5KM range transceivers for wireless network communication.

Altivar 3-Phase VSD for pump control.

Grundfos 3 Phase Vertical Multistage Pumps

12VDC Off Grid Pumps

Solar Panels and controller for Off Grid Pump Station.

Actuator valves, non return valves and a pressure tank to provide the automation of the grey pump filter backwash and suction line purge.

Solar Pumping Station

Irrigation pumps  (12V DC /65PSI) and water tanks. Off the grid solar powered remote PLC control panel with wireless modbus communication.

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