The Greenline shielding design
By using the HBK measurement technology with its special shielding concept against electromagnetic interferences, Trasko Automatyka Sp. z o.o. was able to set up a process control system providing reliable results. They used the following setup:
- A T20WN torque sensor for measuring signals
- The PMX signal conditioning system for production control
- The catman software for measurement visualization and analysis
- Special double-shielded cables to connect the different parts of the measurement chain.
Protecting measurement systems against electromagnetic interference has been a long-time specialty of HBK products. For example, all electrical/electrotechnical components of the complete measuring chain are tested and technical safety issues are analyzed in HBK’s accredited in-house laboratory, thus ensuring that all normative requirements are satisfied.
Finally, a decisive factor for successfully building an “immune” measurement chain in the assembly line was the use of a special shielding design (“HBK Greenline”), ensuring safe and failure-free operation. Greenline-protected equipment neither emits any disturbances into the environment nor excessively loads the mains power supply. Using this setup, the complete measuring chain is fully enclosed in a Faraday cage through the unique design of the cable shield. The cable shield is flattened, connected to the transducer housing, and routed to the amplifier housing through conductive connectors. These measures substantially reduce the effects of electromagnetic disturbances.
Following are practical hints on how to ensure the shielding design: All components of the measuring chain (including all cable joints, such as connectors and couplings) have to be surrounded by a closed, EMC-tested shield. Shield transitions must be realized in the form of flattened, closed and low-impedance joints. This is ensured if original HBK connectors are used.