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Max refuses to configure my SCC-CO20 according to the instructions sent with the unit. Flags it as invalid configuration.

When I configure it with voltage as the actuator, it indicates invalid configuration and doesn't provide my DAQ board in the hardware pull-down lists. If I switch to current as the actuator, I can select my board and channel, but then the test of the system yields error -10007. In neither case do I get current from the screw terminals on the SCC-CO20.
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Mike,

I have a couple of questions:

1. Have you added the SC-2345 as the accessory for your DAQ device in MAX and also configured the module from the same location (Devices and Interfaces >> Your DAQ Device >> Properties >> Accessory)?

2. The instructions you followed to create the virtual channels, were they on pages 13-14 of the SCC-CO20 User Guide? (Link available below.)

SCC-CO20 Isolated Current Output Module User Guide

3. Which version of NI-DAQ are you using? You can find out in MAX, under Software. This could be the cause of your problem because an Actuator of Current should make your configuration invalid, not Voltage.
The most recent version of NI-DAQ is 6.9.3, and it can be downloaded from the following location:

NI-DAQ Version 6.9.3 for Windows 2000/95/98/ME/NT/XP

Let me know.

Spencer S.
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Hi Mike,

***Yes, I am aware I am replying to a very old post***

I have encountered this exact same issue with every version of older NI-DAQ and even newer NI-DAQmx I have ever used.  It occurred with the version that shipped with Labview 6.x all the way up to the latest version, whatever ships with Labview 8.x.  Not to mention the recently recalled NI-DAQmx 8.6.0f12 which I have not tried... and will not!  I have 3 new drink coasters!

Basically here is a crude work around.  First, you can only put the SCC CO-20 module in 2 specific slots on any of the SCC chasis boards. They are the only 2 slots that can handle A/O device modules (either voltage or current output).

All the CO-20 does, is provide a shunt resistor to convert voltage supplied by the board into current.  I=V/R.  My work around is to just configure it in MAX as an FT-01 or a voltage device.  That way, the board just gives it voltage, and magically, by way of the shunt resistor, you get current out of the module.  Then, just convert your values mathmatically in your code.

You can also build your own MUCH CHEAPER "home-made" CO-20 using an FT-01 and a shunt resistor of your choice (usually 250 or 500 ohm.  This is pretty basic current loop stuff, but it works well.  FT-01 modules are only about $30 and a resistor is $0.15.  An SCC-CO20 costs way more than that.  > $200???

NI has in the past just told me I had the SCC-CO20 in the wrong slot (not the case) or some other hoopla. Sadly, I have not gotten much support on this issue.  Once I figured it out on my own, I stopped asking them.  Mainly, because I really dont think anyone understands the problem, or because I have not explained it properly, or because SCC equipment is old and they don't want to spend alot of time on it anymore (which is understandable).  Someday, if ever given the chance, I would like to show this little gremlin to an NI rep first hand.

Anyway, I still say it is a BUG in NI-DAQ but just wanted to let you know, I feel your pain, Brother!  You are not crazy or alone.

Braincramp. 

 

 

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