Tele-monitoring of motor protection circuit breakers

The free, uncomplicated exchange of information between machines and systems is the new vision of self-organizing cooperation with a wide range of monitoring points. The solution is: telematics and web service as the basis for all specifications of inter-manufacturer standards. This will achieve an open network and will make previous, closed (proprietary) solutions a thing of the past.

Introduction

In this day and age of globalization the remote operation and observation of individual components or entire technical processes is an absolute necessity that no manufacturer of technical equipment can ignore.

In the case of equipment that is used globally selected operational conditions can be monitored and evaluated with regard to preventative maintenance.
Spontaneously occurring operational faults are reported to a central service station. Specialists at this station then carry out a fault diagnosis and initiate measures to remedy the problem.

The most important advantages of this technology are:

  • Immediate reaction to system faults in order to avoid subsequent faults
  • Fault diagnosis by specialists in the central office and competent instructions to the local staff in order to remedy the fault
  • Reduction of stoppage times and better utilization of production systems
  • Evaluation of operational circumstances in order to initiate maintenance measures
  • Reduction of personnel costs by eliminating traveling time and costs
  • Determination of operating time in order to calculate leasing charges
  • Determination and reporting of all operational events in databases


This kind of observation and operation project can be easily realized with the availability of reasonably priced, reliable communication modules from mobile telecommunications technology. Some examples of components that can be monitored remotely are pumps (figure 1) for water provision, to pump off ground water and to transfer sewage in water clarification works.

Hardware

Entirely new remote monitoring solutions have been created with the development of mobile communications technology. A GSM module is fitted, just as is found in a mobile telephone except that the acoustic module is replaced by an I/O module.


In most GSM modules this has two digital input ports, two digital output ports and a serial interface.
These input and output ports are sufficient for remote monitoring and operation of a process so no further components are necessary apart from the GSM module. In the event that processes with a larger number of sensors and actors need to remotely communicate then an additional micro-controller is necessary in order to connect them, which in turn communicates with the GSM module via a serial interface.

The sensor and actor signals from the process must then be adapted to the available signal level on the micro-controller. In order to store user software and variables the GSM module, and the micro-controller must have sufficient flash and RAM memory.


Software

There are also various possibilities for the production of the necessary software, depending on the GSM module selected.

The preferred version is the production of software in a Windows environment using a high level language. The compiled user programme should, if possible, be transferred from the PC to the GSM module using a RS232 interface, whereby the PC treats the GSM module as an additional drive.

In order to load the user programme from the PC into the flash memory of the GSM module it must be manufactured with a BIOS or at least a bootrap loader.

 

Communication and transmission methods

A database offers the perfect support for every user in the documentation of processes and management of personnel and equipment.

The database structure should be able to be used by both the provider of the GSM module and the user.

The provider produces and maintains a so-called "PROVIDER database". This contains all the equipment with all the data needed by the user including the telephone numbers of the implemented GSM modules supplied to clients.

Each user now has access to this database but only to the equipment he is using. This does not include an entitlement to make changes to the content of the database. A new client will receive software from the provider to generate a "CUSTOMER database".

He can use this to manage the GSM modules he is using. In order to simplify the creation and maintenance of this database lists are first produced for all equipment groups. These lists include use locations, project names, names and mobile telephone numbers of service technicians, alarm types, input ports on the GSM modules, output ports on the GSM modules etc.

The "CUSTOMER database" contains all the equipment for one user with the corresponding information. A CONFIGURATION MENU is called up in order to create this database. This contains combo boxes for the above-named lists. The user clicks the combo boxes one at a time. After this the relevant characteristics for each application can be selected and allocated from the stored data. This procedure allows the "CUSTOMER database" to be produced simply with the equipment used and the allocated information on:

  • Usage location
  • Project name
  • Equipment type
  • Service technician
  • Alarm type
  • Input signals
  • Output signals

The equipment type with the corresponding information can be found in the "PROVIDER database". During operation the individual equipment can transfer the processed data selected by the parameters to the server via the Internet, where the data is displayed in a status report.

This data is allocated to the relevant equipment in the database and a report is produced. It is then available for further evaluation and can be exported for other applications.

Security precautions

In order to assure the operational security of the remotely installed systems and to avoid access by unauthorized person's security measures can be integrated into the software.

This is possible, for example, by requiring that each person authorized to operate the system must be recognized by the GSM module via a PIN and/or password.

In order to control the functionality of the GSM modules it is possible, when using servers, to request messages from the GSM modules at certain, regular intervals. In the event that one of these messages is not received the server can be used to take measures to clarify reasons and initiate the resolution of a fault if necessary.