I try to use Electrochem PS1 sensors to read the pressure in water pipes. But i can read signals once in every 10 seconds. How can i read signal once in 1 second or in a shorter time than 1 second? Thanks.

 

Rosemount (and others) sell battery powered wireless HART pressure transmitters that are also low power radios. Originally (2 years ago) I understood that the maximum sampling rate for direct connection (not through a repeater) to the wireless gateway is 4 seconds. That might have changed over time.

Honeywell sells battery powered wireless ISA100 pressure transmitters (XYR6000). The sampling rate can go down to 1 second. Their other radio network, the XYR 5000 goes down to 1 second sampling intervals, too, although either are the low powered transmitters with limited range.

The route that I just used is to use a brand x 2 wire, loop powered pressure transmitter.

If 24Vdc is available to power the transmitter, then Banner Engineering's DX-80 I/O radios will do updates faster than one second and Banner radios are far more powerful and shoot longer distances than Wireless HART or Honeywell.

I didn't need one second updates, and Banner's field node radio can be configured to supply power to the transmitter loop. As expected, the battery life is reduced dramatically when the radio battery powers the loop, too. Banner has a 6 cell battery pack to extend battery maintenance.

I found a blog a short while back that tipped me off to the Banner approach:
http://blog.lesman.com/2012/03/07/u...ery-to-power-a-pressure-transmitter/#more-507

or the shortened URL's:
http://tinyurl.com/7yt9oyv
http://preview.tinyurl.com/7yt9oyv

 

This is the reason proprietary wireless tech like Banner's SureCross system is still being used and the use of proprietary tech is growing. (See my interview with Banner's chief engineer Ty Fayfield, and creator of SureCross, in the August 2011 Control magazine-- www.controlglobal.com).

IEC62591WirelessHART can be operated at a faster rate than 1 second. The tradeoff is battery life. I assume the Honeywell proprietary implementation of ISA100 can do that too.

If you want 250 ms update, you need to make the transmitter either a two- or four-wire device and give it instrument power instead of battery. Every WirelessHART device is available that way. You can also use a WirelessHART adaptor on an existing transmitter that is designed specifically for 250 ms update rate.

Walt