6070E available current for controlling modules

[sedao]

We have NI 6070E. from its family specifications, it seems that MAXIMUM 5mA current drive is available at voltage output;
Meant to control 24V 2W solenoid valves, chose SSR ODC5, which requires MINIMUM control logic current 5mA;
Do they (6070E and SSR ODC5) match?

[MarkLe]

Hi Sedao,

Thanks for your e-mail and forum posting about this issue - whether your SSR backplane and modules will match up with your E Series DAQ card (6070).

The figure you quoted for current drive is for the Analogue Voltage output for the card, the AO provides a high precision voltage source in the range 0-10V, but does not supply much current (as you saw +/- 5mA), it is used to provide a reference voltage rather than switch loads of any kind.

The SSR modules you are looking at however, will be driven from the digital output ports of the card, which provide either a 'low' level voltage (0-0.4V) or a 'high' level voltage (4.35V+) without as much precision as the Analogue Output, but with a far greater capacity to source or sink current (they are designed for switching things on and off).

The datasheet for the 607x series specifies that the card can Source (drive out) 13mA when the output is high, and Sink (switch down to Ground) 24mA when the output is low, so either of these modes will have the current capacity to drive the SSR modules.

The SSR series user manual:

http://www.ni.com/pdf/manuals/371174a.pdf

states that the modules do need the DAQ card to sink current from them, therefore the 6070 will be able to switch a module requiring anything up to 24mA, so should be fine for the SSRs you are using!

Best wishes,

Mark

National Instruments UK and Ireland

[sedao]

Very useful info, comprehensive explanation. Thanks a lot

[sedao]

Hi,

I am thinking about the cable distribution and connections:

The one 6070E I am using now has been occupied for some AI works. A SH68-68-EP cable connects the 6070E and 68pin connector block.
In this circumstances, would I be able to get this 6070E connected with SC-2050 to drive SSRs? If I would, should I buy SH6850 cable, how to distribute the cables/connections?

Thanks
sEdAo

[MarkLe]

Hi Sedao,

Thanks for your second question about connecting your 6070E to the SSR backplane.

You will be able to connect this card to the 2050, either by buying the cable you suggested, or you can use your existing cable with a 68M-50F connector adapter, as described in this KB (which is talking about interfacing M series, but the principle is the same for the E series):

http://digital.ni.com/public.nsf/websearch/9D688D259C0D796748256F7D0080FC4F?OpenDocument

You can then connect the relay backplane on from the 2050 using the SSR connection cable from connector J5. If you still want to use the AI lines in this configuration with the accessory, you can do this because the 2 50 pin connectors (J1&J2) on the 2050 are daisy-chained - so you can connect your accessory onto the second (unused) 50 pin connector on the 2050 using either a R6850 (or SH6850) or a 6868 cable with adapter (as above).

You can also access the analogue input channels directly from the accessory J3 - 26 pin male connector, but we only sell cables to connect this through to the 5B range of accessories, not the accessory you are using at the moment - I would recommend using the solution above.

Page 2-4 of the SC-205x Series User Manual discusses all of these connections in more detail, you can find it here:

http://www.ni.com/pdf/manuals/371176a.pdf

I hope this helps!

Best wishes,

Mark
National Instruments UK & Ireland

[sedao]

very helpful. xoxo