In the industrial field, measurement, control and automation devices are exposed to many potential interferences. The absence of adequate protective circuits can have serious effects, not only on the measurement and control electronics, but also on the whole application.
Our experience – your benefit!
From the beginning, ADDI-DATA has attached great importance to the protection of customer applications. For now 30 years, we have dedicated ourselves to the development of robust industrial products. Thanks to numerous protective circuits, our PC boards, distributed solutions and accessories provide for a maximum of protection between the control unit and the peripherals.
Interference-free products by ADDI-DATA are equiped with filters for inputs and outputs and are protected against short-circuits, overtemperature and overvoltage.
Protective measures also make sure that ADDI-DATA products themselves do not emit high levels of EMC radiation into their surroundings. This could heavily affect the devices in the immediate surroundings, with particularly serious consequences when used for medical purposes.
In order to avoid emissions, all ADDI-DATA products are tested for CE conformity, i.e. the conformity with EU directives, in accredited laboratories.
The importance of protection
The use of non interference-free products may have serious effects, especially in harsh industrial environments:
- Measuring errors
- Noise in the signal
- Malfunction or destruction of the hardware
- Complete failure of the control unit
PC boards: Developed for industrial use
With analog signals, a differential signal transfer is generally recommended. As opposed to single-ended acquisition, the difference between two signal lines of a sensor is established here. If there is interference on one signal, both signal lines are simultaneously affected. The interference is therefore easily avoided using the differential calculation.
Measurement chain when using PC boards
Optical isolation up to 1,000 V also guarantees the interference-free operation of ADDI-DATA products. Using opto-couplers, AC/DC converters and plug-in connectors prevents rapid transients, overvoltage and ground loops. The layout has a creeping distance of 3.2 mm in accordance with the IEC 61010-1 standard.
For protection against high-frequency interference, ADDI-DATA uses low-pass filters, which block interferences from the signal. They can be individually adapted to customer requirements.
Ethernet systems: Protection through closeness
For a better protection against interference, it is a good idea to move closer to the measuring point. This is possible with the MSX-E series of intelligent Ethernet systems and the real-time open source PAC system from ADDI-DATA, the MSX-Box. With these products, you can reduce the cabling and thus exposure to interference, and the same protection measures apply as for the PC boards.
Measurement chain when using Ethernet systems
In order to provide additional interference resistance, the MSX-E systems have a robust metal housing which protects against EMC radiation, vibrations and temperature. The MSX-E systems have been developed especially for an extended temperature range. The MSX-Box functions as far as possible without rotating parts, enabling it to be moved closer to the application itself. The advantage of distributed solutions: Acquisition very close to the measuring point reduce the risks of interferences having an inpact on the measurement data.
What is the most important task which must be performed by peripheral hardware? It should run without interference and reliably transfer data. Just as reliably as the connected PC board or the Ethernet industrial measurement system. For this, ADDI-DATA offers a varied range of dedicated accessories. Perfectly matched to the PC boards and Ethernet systems they too meet the requirements of use in harsh industrial environments.
Screw terminal panels, relay output boards or connecting cables – the same high standards of reliability and EM compatibility apply as for the PC boards or Ethernet industrial measurement systems themselves. For example, we use D-Sub connectors which are robust, interference-free and provides a high protection against electromagnetic fields.
Structure of ADDI-DATA twisted-pairs cables
On a cable with a D-Sub connector, the cable shielding is connected all round the metal cap of the connector. Thus the cable is earthed at both ends, which is essential for shielding against electromagnetic fields.