When it comes to automation solutions for water treatment applications, there are plenty of options. From a standalone station supervising a single pump to a more complicated system of multiple stations with a two-way communication. Here, we are going to look at the case of a double-pump station, which is being constantly polled for data from the centralized SCADA system.
Water Treatment Application
Solutions
The controller we are going to consider for this task will be the XLe, Horner’s most compact and most cost-effective device on the market (we also recommend the touch screen version: XLt). In a case like this, with a pump site in a remote location there’s no need for a device with a bigger screen. This time the screen will be used entirely for maintenance and debugging. The rest of the monitoring should be fully covered by the SCADA system.
Of course the application itself can be as advanced as the programmer wants it to be, but there are few key procedures that our application should have. These would be: Manual/Auto mode, Alarm Handling, Communication (for example via GPRS) and local Data Logging to reduce polling rates of the SCADA.
Our pump station in auto mode would be responsible for maintaining the level (of water, sewage, etc.) between the set low/high levels. The program should also alternate the workload, so the usage for both pumps is close to equal. If the emergency level is reached, both pumps should immediately be switched on. Manual mode is most often used for maintenance and allows the operation of both pumps.
Reporting to the main station could be done in several different ways, for example via GPRS modem, radio modem or Ethernet connection. Because of the remote location of our site the first two options seem to be the most appropriate. The central SCADA system is usually responsible for dozens of similar sites so the connection speed has to be taken into account.
Cscape Demo
The file consists of:
- sample hardware configuration (XLe + GPRS modem)
- Overview screen (Screen 1)
- Datalog Configuration (menu Program -> Datalog Configuration…)
- Alarm messages configuration (Screen Editor -> menu Config -> Alarm)
- GPRS configuration (menu Program -> Messaging -> GPRS…)
- Code for auto mode (Logic Modules -> Main Loop Modules -> Main -> Auto_Mode)
- Code for handling Communication (Logic Modules -> Main Loop Modules -> Comms)
- Code for handling Alarms (Logic Modules -> Main Loop Modules -> Alarms)
(Cscape 9.10B or higher needed)
You can choose from four different I/O models of any XL series controller. In case the embedded I/O does not fully cover your needs you can always add a module from the available I/O Systems.