Pressure Switch

The data looks like it is for three switch settings. As none of these comes anywhere near the line setpoint settings, one wonders if this data is for the same piece of equipment?

As far as the differential is concerned, it may well be that the setter has no option on the matter, and this is simply the reading obtained from each switch setting. It is usual for the transition point between one state and the other to differ between rising pressure and falling pressure.

If the differential (or deadband) is small, the process will have closer control, but the item controlled (compressor, valve, etc.) will cycle on and off more often.

Conversely, if the differential is large, the process will be less tightly controlled, but the equipment will cycle on and off less often.

Thus there is a trade-off. Your choice will depend on what is more important to your process: tight control or fewer starts/stops and less wear on equipment. It also depends on what differential ranges are available for various models of pressure switch.

Figures look good to me (tho' you didn't say what the datasheet said about hysteresis).

If you need tighter control, get a "better" (lower hysteresis) switch - or consider using an analogue transducer and a PID controller.

more details about data sheet

service & location for this witch is : sales gas

output action : open on high pressure

pressure element : diaphram

model/manufacturer: zppx-p160 /waaree instruments

calibration looks strange because of so high dead band.

my question is is this the right way of calibration

thanks

What does the switch manufacturer have to say on the topic?

Hi,

What the switch manufacture should say is in this website: http://www.atc-inst.com/ , you can check it now!

AMERTEC

The manufacturer's datasheet states that the differential is fixed (but doesn't specify it). It also states that the repeatability is ±1% and the scale accuracy is ±3%.

The figures you've quoted for the calibration show that the setting is spot-on (the switch cuts off at the set pressure).

A differential of 35psi at your working setpoint of 1415psi is less than 2.5%.

Unless I'm not understanding your question, I don't see any problem. Can you explain more?