NI-PCI-6010 Questions

[baris_oz]

Dear NI Tech Support,

I am working on a master thesis that is about positioning control of a pneumatic system. Actually I am working with a DAQ device first time, so I don't know much about it. I need to produce 4-20 mA to operate my valve (5/3). As I understand from the datasheet, I cannot produce 4-20 mA from PCI-6010. First of all, is this true? And if it is true, can I put a resistance that is 250 ohm in front of one of the Analog Outputs (1-5 V) to drive valve and is it safe?

I have found another solution about it. It is said that I can use an Inter-Integrated Circuit (I2C) to resolve this problem, but i don't think it's necessary because PCI-6010 already has DAC, is it right?

Sorry for bothering you with this simple problem, but I couldn't find any other support. 

Thank you in advance.

[KateB · Accepted solution]

You cannot simply connect resistor to 6010 AO and make it drive 4-20mA due to two reasons.

1. 6010 AO can drive +-5mA only.

2. You didn't put load into calculation and that would make current varying.

One of possibility is to use active voltage to current converter connecting to 6010 AO as found in http://en.wikibooks.org/wiki/Circuit_Idea/Op-amp_Inverting_Voltage-to-Current_Converter

[baris_oz]

Thanks for replying.

Any thoughts about XTR110? You can look at its datasheet from; http://www.ti.com/lit/ds/symlink/xtr110.pdf

And one more question, as seen from the specifications of PCI-6010, its analog outputs have a range of -5V to +5V, did I understand it right and if i did, can i use it 0-5V or 0-10 V ?

[KateB]

For a circuit, you never try, you never know. For AO, just +-5V, not 0-10V.