water quality probes and pcb design

Jul 09, 2014 3 Replies

Hi.



Am building one let's say plc board around dspic. We are almost finish with the schematics part but now i run into one problem. The PCB, among bunch of other stuff, should have inputs for water quality probes. At the begginig there was just temperature probe



Searching on the net i found one very good product.

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So under description is stated that this probe can be connected over rs23/485 which is ok for me.



Did someone of you used such probes and/or try to write a mcu program ?


Just a few questions:

I have done analytical chemistry (HPLC, GC, etc.) - what exactly are trying to measure?

Which dspic are you using? I have used pic24FJ128GC010 but probably overkill.

You are in the area of analytical chemistry. I note the probe has a fDOM feature - what is the sensitivity and specificity of it? Any docs?

I'd be on guard that the probe just measures water resistance at the end of the day.

To repeat myself, what specifically are you trying to measure? Water resistance does not measure dissolved organics like CCl4.

jb

Thank you for reply. Am using dspic33FJ128 , 100 pin count because the board is like one small PLC with bunch of things.

Regarding your question:

- the program is user defined so end user will define what he need on the field. At the moment i know just few things and one of them is that this probe should be used for temperature, ph and depth measuring.

Data will be send over RF to the nearest centre ( cca 300 meters clear view ) and saved on the PC. Other option is to read the data directly on the site. This is the part where i have problems because i dont have much info regarding this probe. Can the probe be connected to the

485/232 port of MCU ?

If so then i guess that the probe is sending formatted serial data, that could be read as standard serial data. Or ?

en2 wrote in news:lpk124$o2r$ snipped-for-privacy@l01news1.ot.hr:

The sensors you mentioned use either Bluetooth or USB tot communicate.

The processor you mentioned supports RS232/RS485 (except for the voltage levels) so programming this micro should be straight forward... If the sensors used RS232/RS485.

FAIK the micro does not support USB so you'd have to look for another PIC or for other sensors.

BTW This PIC is a very powerfull device. It looks like serious overkill to use this device for only collecting and sending data.

petrus bitbyter

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