Using Counter Outputs

[James P. Martin]

Hello to all,

I am using a DAQ 6221(68 pin) card , for various analog inputs, but have no idea how to use counters to get a 5V DC output as a pulse train. I have an application in which I will be controlling the temperature through Heaters which will be On & Off using SSRs(solid state relays).

The SSRs operate at 5V DC so I am thinking that if I can use the counters to operate the SSRs so that they switch as per the counter outputs(5V DC) which comes as a Pulses....by pulses I mean if my temperature is far below the set point so I will generate a 100% duty cycle pulse so that relay keeps on for full time...and as temperature approaches the set point the pulse width keeps on decreasing.

So experienced programmers please put some light on my query , and I want to know which terminals I have to use as 5v DC output in 6221 DAQ card.

Regards

[i2dx]

QUOTE(James P. Martin @ Feb 17 2007, 09:33 AM)

Hello to all,

I am using a DAQ 6221(68 pin) card , for various analog inputs, but have no idea how to use counters to get a 5V DC output as a pulse train. I have an application in which I will be controlling the temperature through Heaters which will be On & Off using SSRs(solid state relays).

The SSRs operate at 5V DC so I am thinking that if I can use the counters to operate the SSRs so that they switch as per the counter outputs(5V DC) which comes as a Pulses....by pulses I mean if my temperature is far below the set point so I will generate a 100% duty cycle pulse so that relay keeps on for full time...and as temperature approaches the set point the pulse width keeps on decreasing.

So experienced programmers please put some light on my query , and I want to know which terminals I have to use as 5v DC output in 6221 DAQ card.

Regards

I don't think you need an "experienced pogrammer", you just have to have a look at the example finder, and use one of the "pulse train generation" examples

http://lavag.org/old_files/monthly_02_2007/post-885-1171702212.png' target="_blank">

just if you have never seen the example finder: click "Help" --> "find examples"

[James P. Martin]

QUOTE(i2dx @ Feb 17 2007, 03:50 AM)

I don't think you need an "experienced pogrammer", you just have to have a look at the example finder, and use one of the "pulse train generation" examples

http://lavag.org/old_files/monthly_02_2007/post-885-1171702212.png' target="_blank">

just if you have never seen the example finder: click "Help" --> "find examples"

Thanks for the prompt response

Could you please also explain on which terminals I would get that 5V DC pulse train and what are the connections I must do.

Regards

[Jeff Plotzke]

QUOTE(James P. Martin @ Feb 17 2007, 06:25 AM)

Could you please also explain on which terminals I would get that 5V DC pulse train and what are the connections I must do.

Regards

I would suggest taking a look at the M-Series DAQ Manual here: http://www.ni.com/pdf/manuals/371022g.pdf

Page 7-19 (Page 117 in the PDF) shows the counter outputs applications.

Page A-6 (Page 172 in the PDF) shows the pinouts for your PCI-6221 DAQ card.

So, if you're using counter 0, the pulse train output will be on pin "CTR 0 OUT", pin 2 of the DAQ card. Use any of the "DGND" pins for a ground connection.

[Chris Davis]

You might also want to check how much current your SSR's need to function, the counters the DIO ports don't provide much (~180 mA).