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drdaq + EC + ph + some questions

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drdaq + EC + ph + some questions

Postby mouton1664 » Thu Feb 10, 2005 10:06 am

i m a french user of drdaq, so excuse me for my poor english

-I want to know how can I connect EC probe on drdaq ?
- in drdaqscl.c in the linux kernel driver i found

{"Sound Waveform", "Sound", 4, 0xE0, 1200},
{"Sound Level", "Level", 3, 0x10, 1300},
{"Voltage", "Volts", 2, 0x90, 1500},
{"Resistance", "Ohms", 1, 0x50, 1600},
{"pH", "pH", 5, 0x60, 1400},
{"Temperature", "Temp", 10, 0x80, 1100},
{"Light", "Light", 11, 0x00, 1000},
{"External 1", "Ext1", 6, 0xA0, 0},
{"External 2", "Ext2", 8, 0xC0, 0},

/* 10 and 11 are detects for Ext1 and Ext2
{"Detect 1", "", 7, 0x20, 2000},
{"Detect 2", "", 9, 0x40, 2000},

I think is false i have invalid data.
Can you give me the good order of channel to use?

- I dont found the scale array for PH in linux include (.h)
Drdaq is a great product and i hope i can use it under linux it s really important.
I know there is no support for linux but if you have any informations about this thanks to reply me.

Posts: 2
Joined: Fri Dec 17, 2004 12:58 pm

Postby Sarah » Mon Feb 14, 2005 9:34 am


Thank you for your post.

You need to measure conductivity by passing a square wave into the sensor. If you then rectify the signal out of the sensor, you should get a voltage proportional to conductivity. Either that or you could try and source a signal conditioner that will get give you a voltage output.

I'm not sure why you aren't getting any data. The table you describe is correct so there must be a problem elsewhere.

Scaling can be added for pH by adding this as a header file:
static SCALE_POINT sp_ph [] = {
{ 1422, 1000},
{ 2038, 700},
{ 2655, 400},

Hope this helps

Best Regards

some questions

Postby mouton1664 » Mon Feb 14, 2005 3:41 pm

in thread

How do I convert the DrDaq sensor values under Linux?
i see that channel order seems to be
sound level=3 light=6 temp=11 ( for temp i am not sure it s good )
and in your table you ve got sound_level=3 temp=10 and light=11
when i try temp=10 light=11 i got -0,10°C for temp

I will continue to try diiferents channels to have to good values

Do you sell Ec probe for drdaq ?
Do you sell C02 probe for drdaq ?

Thanks you a lot for infos and time to answer.
Best regards
Posts: 2
Joined: Fri Dec 17, 2004 12:58 pm

Postby Sarah » Tue Feb 15, 2005 11:02 am


Thank you for your post.

I am not too sure what you mean by an Ec probe. We do not unfortunately sell a CO2 probe. A full list of all the DrDAQ probes we sell can be found on the DrDAQ website at www.drdaq.com

With regards your linux questions, I am afraid we are unable to answer them. Linux drivers are offered as a service to Pico Technology customers and do not fully support every function in every product. Whilst we will do our best to help Linux customers, a timely response to questions or problems can not be guaranteed. We do not at present have anyone with enough linux knowledge to be able to answer your queries. There may be someone on the forum who can help you.

Best Regards

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