GPRS WELL TO TANK CONTROL
In one of our previous application notes we showed you how SMS well to tank control works. This one on the other hand will show you how that is done via GPRS using GT900 line of products. Our GT900 line can operate in different modes – GPRS Router, SMS Reporter, SMS Gateway. Further text will show you the GPRS Router function.
It is a very common situation that you have well with pump on one location, and water reservoir on a completely different, remote location. These locations are usually on inaccessible terrains, and it would be very expensive and inefficient that workers check manually levels of water in tank. Also, if you would try to refill reservoir on a hunch you are facing two problems – because consumption is not linear, and depends on circumstances, you could possibly have situations that your tank is empty for periods of time, and also that you are overfilling it on the other.
This version of DECODE solution will consist of devices from GT900 family, but this time in GPRS Router mode. Main difference is that this kind of configuration gives you possibility to control whole system from one center (point to multi-point). Also you can make smaller circles of regulation between devices on locations, under the supervision of device in control center. Big advantage of our routers is that all routing can be done directly on the device. You can set up devices using our free GSM Utility software. In this kind of communication you have constant flow of data, opposed to SMS Reporter where data is send periodically. All you need are SIM cards in VPN.
In Control Center you have PC with SCADA on it. Here you have master GT900-110 device that can call up and gather data from all other devices. Also, through SCADA software you can give commands to activate/deactivate relay output of slave devices, generate alarms, notifications for maintenance crew etc. It is connected to PC via DECODE DC USB-RS232 ISO converter with galvanic isolation that protect devices from over-voltage.
On this location we have accumulation of water (lake) and pump that is refiling tanks when water in them gets on designated low levels. The pump is controlled via variable drive which is connected to GPRS Router via Modbus. The router in control center gets information from tank that water level is low. Then, that device sends signal to router in control box pump to activate the pump. When water level gets to designated high level, whole process is repeated with intention of shutting down the pump. We also have in this cabinet 3 EMU devices with task of monitoring voltage, current and analog values and sending information via Modbus through router to control center. They have important role in predictive maintenance and possibility to early show problems with pump based on wrong values of these factors.
As we already mentioned, tank is usually located on remote locations, on inaccessible terrains, without maintenance workers near by. That’s one of the reasons why remote control is logical choice. But lack of infrastructure on these locations can be problem for power supply. That is why our cabinet in this solution is equipped with solar panel and battery. DECODE Solar charger is a device that primary powers consumers and charges the battery from the main voltage. If the voltage of the solar panels is high enough, the device automatically powers the system directly from solar sources. Lead-acid batteries are commonly used in battery-powered systems that require protection from overcharge and deep discharge. In this control box we put GPRS Router 343, same type of router as 110 just with different hardware configuration – 3 relay outputs, 4 optocoupler inputs and 3 analog inputs. This excess of inputs you can use for different kind of alarms (open windows, open doors, high temperature etc.) or anything that you think is important to get notified about.
On other remote locations you can have several draining wells. For this example we took one location with PLC, our GT900-110 and one digital sensor. Control center can read data from PLC or from internal Modbus map of router (data from digital input). This is achieved by setting IMSA parameter on device that is used for identification of inquiry. If router recognizes IMSA parameter it responds from his Modbus map, if it doesn’t an inquiry is forwarded to serial port. This configuration also gives you possibility to set PLC remotely.
Here we tried to show you more complex application of our routers and what you can achieve with just a couple of our devices. This is just a suggestion, you can take some parts of this solution, and use it, or design completely new based on ideas that you saw here.
Decode Marketing Team