Reference: Retrofit of the fountain system at the station square in Bad Saarow
The station square in Bad Saarow is characterized by the fountain "enjoyment of life" by the sculptor Hans Eickworth and well-kept green areas. To irrigate these, various cisterns are filled by a deep well pump. In order to increase the availability of the attachment, a suitable measuring system is to be installed here.
Eike Kammer, Project Manager Retrofit
+49 (0) 3375 2131-155
E.Kammer@eaw-relaistechnik.de
Problem
Strong rainfalls and overflowing cisterns, a blocked deep well pump and empty cistern pumps. In the past, office employees often had to check on site in order to be able to detect defects and malfunctions of the system, or unwanted conditions were registered too late.
In order to relieve the burden on employees and increase the availability of the system, the customer wants a reliable and robust measuring system to be able to record the limit levels of the cisterns on the one hand and the water entering the deep well shaft on the other. The correct functioning of the deep well pump should also be monitored.
In the event of unwanted conditions and malfunctions, the responsible office employees should be informed immediately via corresponding messages on their work mobile phones as well as by e-mail in order to be able to act quickly and specifically in the event of an error. The checking of the system condition, previously only possible through an on-site inspection, will in future be carried out remotely using a status query.
Result
As a result, we were able to offer the Bad Saarow office a tailor-made solution for the specific application. The office employees now benefit from a solid and reliable measuring system and are regularly provided with information on the status of the plant. If an error occurs, the relevant employees are notified immediately. This means that they know immediately where and which error has occurred and can take targeted measures.
Performance
Measurement and monitoring technology
Ultrasonic sensors were installed in the respective cisterns to record the limit and fill levels. Ultrasonic sensors are analogue measuring systems that allow continuous measurement of the fill level of the cisterns. The advantage of this measurement method is, on the one hand, the possibility of free parameterization of the limit levels as well as the implementation of a variable number of limit levels. Furthermore, these measuring systems are extremely robust, maintenance-free and durable due to the non-contact measuring principle.
To protect the system, the deep well pump, which is responsible for the continuous filling of the cisterns, is switched off in the event of a fault via a corresponding contactor in the load circuit. The proper functioning of the deep well pump is realized by means of current monitoring relays in the load circuit, which realizes the following monitoring functions.
- Monitoring for current overshoot and undercurrent
- Monitoring for phase failure/line break
- Underload monitoring in the lower power range - pump idle
- Monitoring for overload - dirty filter system or blockage
- Monitoring for imperfect ground faults, e.g. due to damaged insulation or moisture
Control technique
A Siemens S7-1200 was used as the control technology for this project. This is where the measurement results are evaluated and the power contactor is controlled. Furthermore, the message management and the dispatch of alarm and status mails to the official employees is carried out via a secure SMTP connection with TLS.