PROFIBUS PA and Foundation fieldbus bus terminator
VBT10 is a bus terminator for PROFIBUS-PA and Foundation fieldbus (FF) digital networks. Developed according to the IEC 61158-2 standard, it consists of a series RC circuit, where components of high precision and low temperature variations are used to guarantee the perfect impedance matching and minimize signal reflections.
Some details of your application:
- 02 bus terminators must be connected per Profibus PA or Foundation fieldbus network segment, one at the output of the DP/PA coupler or power supply impedance (FF) and the other at the last device, depending on the adopted topology.
- If there is a junction box at the end of the main trunk with several spurs, the bus terminator can be connected at this point, which will facilitate maintenance when it is necessary to remove the field device. But, if the spurs have different lengths, the terminator must be placed at the end of the longest spur to avoid reflections.
- A missing terminator or its connection at the wrong point degrades the signal due to the antenna effect.
- A missing of a terminator can increase the signal by more than 70% and an additional terminator can attenuate the signal by up to 30%. Under these conditions, the communication signal may have intermittent failures.
VBT10 has a reduced and robust design, providing easy installation inside junction and protection boxes, as well as in the terminals of field device.