Gelizha, essence safety barrier is stem what of, the simplest answer is the limit, limit pressure (voltage), is to prevent the risk of large current or high voltage signal into the dangerous scene (the most widely used is the petrochemical industry)
Such as oil industry, the scene is a flammable and explosive substance, the scene of the security of 20 ma current, if more than 20 ma current when a sudden increase, then the security grid work.
Application overview
Industrial field generally need to adopt two wire transmission mode of distributor, should not only provide an instrument such as pressure transmitter with 24 v power supply, and the input current signal acquisition, amplification, after operation, and anti-interference treatment, then output isolation of current and voltage signals, or other instrument for the back of the instrument for use.
But some special industrial field not only need two wire transmission, distribution, power supply and signal isolation function provides both at the same time also need to type with intrinsically safe explosion-proof performance, reliably prevent power between high voltage and signal mixed, use the doubling limit loop current, voltage, restricting energy into dangerous places under the safe norm has special function of distributor & ndash; Security gate.
There are two types of security grid, the security gate and the operating end. The test end safety grid and the two wire converter are used; The operating end safety grid is used with electrical converter or electrical valve. There are also type isolative security grids, such as signal input.
The adoption of the isolation type safety barrier pressure limiting, current limiting and isolation measures, not only can prevent dangerous energy from the terminal into the dangerous site, improve the system of the explosion-proof performance, but also increase the anti-interference ability of the system, greatly improve the reliability of the system is running.
Working principle
After the DC-AC-DC transformation, the output module circuit requires a variety of voltages.
Detection end isolation type safety barrier principle is: will be on this Ann energy limit circuit module circuit input current or voltage signal into 0.2 1 VDC, into the module after the acquisition, amplification, computing and anti-interference treatment, then through transformer adjustable output isolated current and voltage signals, or other instrument for the back of the instrument for use. Module also need to output a 18.5 ∽ 28.5 VDC isolation voltage, using the energy limit circuit as a two wire system supply voltage transducer work. The benan energy restriction circuit can limit the high current or high voltage hazard signal to the dangerous scene.
Operating side isolation type safety barrier principle is: the regulator or the operator output of 4-20 ma DC output signal isolation after 4-20 ma DC signal, using the energy limit circuit supply electrical converter or electrical valve positioner field use.
The benan energy restriction circuit can limit the high current or high voltage hazard signal to the dangerous scene.
- Overview of isolatio…
- The use of isolation…
- MDSB309E series oper…
- MDSB309E series oper…
- MDSB308E series end …
