จำหน่ายเกจวัดแรงดัน Pressure Gauge ทุกยี่ห้อ

ศูนย์รวมเครื่องมือวัดความดัน

Setting the switch points of an electronic pressure switch for an application in the vacuum range is not a self-explanatory task. The next article therefore explains what should be taken into account with this particular setting. It involves a pressure switch with a hysteresis function. Instruments with this particular configuration are most regularly installed in industrial applications.
Electronic pressure switches, including the WIKA models PSD-4 and PSD-4-ECO or the A-1200 pressure sensor with IO-Link, operate as ?normally closed? or ?normally open?, based on the task. เพรสเชอร์เกจ illustrate both switching functions with the respective switch and reset points:
In principle, the next applies: The switch point (SP) is higher than the reset point (RP) and the start of measuring range (MRS) is definitely smaller than the end of measuring range (MRE). This rule can be easily understood with settings for ambient air pressures.
Example: Control of a vacuum pump
On the other hand, setting the switch points in the vacuum range and thus, ultimately, the switching function, requires more attention. To illustrate this, let?s take the control of a vacuum pump, for instance, which must maintain a vacuum between -0.7 bar and -0.5 bar. For the task described, we decide on a pressure switch with a measuring range of -1 ? 0 bar.
The beginning of measuring range (MRS) is therefore -1 bar, the finish of measuring range (MRE) 0 bar. This means: At 0 bar (= start of operation) the switch should be closed, so as to activate the vacuum pump. If the pressure drops to -0.7 bar, the switch must open and stop the pump. As soon as the pressure reaches top of the limit value of -0.5 bar, the pump should once again start and run until the pressure has again dropped to -0.7 bar.
ow must the switch points be set within this vacuum range? Let?s take both pictures and translate MRS and MRE:
Here it is clear that the ?normally open? function must be selected, otherwise the pump would not switch on. After entering the switch points, the schematic is obtained, which shows how the pressure switch functions relative to the example:
Note
Information about WIKA?s electronic pressure switches are available on the WIKA website. Would you like to buy pressure switches? In our WIKA online-shop you will find some of our standard designs. Should you have any questions, your contact will gladly help you.
Also read our posts
What’s meant by the switching function ?hysteresis? with electronic pressure switches?
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What is meant by the ?normally open? switching function with pressure switches?