trigger external relay with pci 6024e

[patelka]

Hi

I am very very new to whole NI and Labview and control systems. I am a student working on a project for one of my course. SO please be patient with my questions. Please let me know I didn't provide enough information or am too vague.

Currently we have SCXI 1000 chasis with SCXI 1120 and SCXI 1180 that are used with PCI 6024E. Only one analog output is being currently used through SCXI 1180.

I am going to attach one optical encoder to the system through SCXI 1180 to the counter terminal.

Now I have to control about 10 relays. I was thinking of buying SCXI 1160 with SCXI 1324 terminal block.

I would like to control two more switches. The problem is the they are to be placed in high current line (12-15A). I was wondering if I can control external high-current relays through the remaining DIO terminals of my PCI 6024e card. If I can do this then what would be my coil ratings for these relays?

I would appreciate any insight or possible solution to this.

Thanks
Keyur

[Yardov]

Hi Keyur,

I am glad you are asking those questions because they are very common and are not naive at all.
Unfortunately we do only have one device that can handle up to 12A, more than that, you will have to use other relay. If you want to use one of the remaining DIO lines (I think there are only 4 for your card), then you will need to have a relay that can be driven with at most 24 mA and 5 V. Look at the specs in this link for these numbers.
Other solution is to use one of those relays to turn on other higher current one.
Hope this helps.

[patelka]

Thanks Yardov, that was very helpful.

Just for clarificaiton, SCXI 1160 is completely independent of the PCI 6024E card, but the signal from SCXI 1120D does goes to the 'analog inputs' of the PCI card. is that correct?

So, where does the excitation signal for the switches in the SCXI 1160 card, comes from? is it the chassis that takes care of it?

Thanks again.

Keyur

[Henrik_Volkers]

Is your high current AC or DC?

If AC you might use solid state relays with 5V input and use standard DIO lines (have a look at the max. current spec).  Here is one http://pewa.panasonic.com/pcsd/product/ssr/pdf_cat/aqr.pdf I found at digikey, but look for something similar at your fav. dealer.

[Yardov]

Hi Keyur,

The SCXI uses one AI from the DAQ card for all analog measurements (if is configured in serial mode which is default).
The excitation signals for the 1160 comes from digital lines. This does not mean that the entire current comes from those lines directly. SCXI chassis makes sure to use as much power from his AC connection and respond to DAQ commands.
The Getting Started manual is a great source to understand each module and the general use of the SCXI.

Hope this clarifies more how the system works,