Sensors and Measurements
We have a set of several measurement systems, which are used in a wide variety of applications. This includes simple measurement circuits e.g. for measuring voltages and currents with analogue input and analogue output as well as interface boxes with several analogue and digital inputs and digital output via bus signal.
If required, our measurement interfaces are designed to operate in high noise ambient, e.g. in converter power stages.
Basic Measurement Circuitry
For common applications like measuring DC-link or phase voltages and temperatures we use our well known circuits, which can be adapted to a wide range of applications. The measured signals are well filtered then amplified and then converted to a digital dignal for our control systems.
As an example the bandwidth of our basic measurement interfaces includes the following:
- Dc-link voltage up to 4 kV
- Dc-and ac currents from amperes to kiloamperes
- Temperatures e.g. NTC of IGBT
- Flow rates
Sometimes the signal measurement cannot be realized effectively or economically with self-made interfaces. This is for example the case if voltages are too high or signals are too fast or both. In this case we can take commercially available measurement systems and integrate them into our system. For example an oscilloscope is taken to measure fast transient overvoltage in switching moments. The oscilloscope itself is fully digitally controlled by our system and the measured data is also taken by our system. Consequently, the complete evaluation and visualisation is done with our system and the user does not need to set up several measurement systems and gets the performance he needs.
In many applications the signal that needs to be measured is far away from the control system. For these applications we build customer specific I/O boxes which are used to interface several sensors with the control system. Additionally, these boxes provide outputs to control external circuitry. In order to achieve minimal time delay and robustness against electromagnetic interferences the data is transferred via our MerkurLink bus system.
As an example a multipurpose I/O module might include the following interfaces:
- Three 230 V ac inputs for phase voltages
- Four analogue inputs for the connection of current sensors
- One analogue input for an external dc-link voltage measurement
- A few ports to connect some temperature sensors
- A relay or PWM-output to control a fan
Don’t hesitate to ask us for your application, we will find a custom solution for you.
Additionally to the obvious applications our measurement systems are also developed for the following applications
- Measuring leakage currents
- Observing IGBT driver supply currents
- Evaluating switching overvoltage
- Checking voltage ripples