digital output for NI6009

[Dennis_Knutson]

ELIMINATE the case structure.

[Samsur]

Thanks a lot Dennis. Now I can send digital signal to 3 channels, but I need +5V. Now I get three  -5 volts  output in ref to common. But when I change the polarity the output goes to +1.3V.(This time the output was connected to 3 SSRs).Please direct me  what I am missing here.

Thanks

[johnsold]

That sounds like a hardware problem.  How do you have the SSRs wired? Are all the grounds connected properly? What are you using to measure the voltages you reported?  How much current does the input of the SSR require?

Lynn

[Samsur]

Hi,

SSRs are required at least 4 V to turn on . It has polarity. Before going to SSR let me tell you 6009 output first. It has 12 digital out, from where I am using 3 pins to supply 3 voltage. but those volts are negative in ref to port 0.1 , not in ref. to GND. I am unable to supply 3 indidivual +5Vs in ref to GND, however this is my requirement. What might be the problem? 

The port config is attached, Thanks

Samsur

[johnsold]

How much current do the SSR inputs require? The 6009 digital outputs can sink 8.5 mA and can source 8.5 mA in active drive mode, but the output voltage may be between 2.0 and 3.5 V.

Some SSRs require more current than the 6009 can supply.  Operating the device so that it sinks current rather than sourcing current gives you slightly more drive.

How do you have the SSR wired to the the USB-6009, including any connections to power and ground?

Lynn

[Samsur]

Hi Lynee,

Our SSR draws only 1.7 v and as low as 1.5 mA current to turn on. Using an independent power supply I can turn on SSR. But when I connect 6009, the voltage drops down to 1.25 volt and current to 1.06 mA. Do you know which pin I have to connect to get high voltage? and how? I need 3 digital out that can control 3 SSRs independenly?

Thanks

Samsur

[SnowMule]

+1 for sinking current rather than sourcing it.  Hook up one leg of the SSR to +V and drop the DO line to ground to turn it on.

With the 6009, the default power-up state is high (pull-up resistor), so the SSR will effectively "default" to off with this configuration.

[Samsur]

Please calrify, I did not understand the first line,  '+1 for sinking current rather than sourcing it '.

Please indicate the pin number that I need to connect to SSR.

 Thanks

[SnowMule]

Where you've got one line tied to ground and pull the digital output high to turn it on, tie the line to +5 instead and drop the digital output low to turn it on. Invert the logic in software.

The digital outputs on the 6008 can sink a lot more current than they can source.

[apok]

give us the spec sheet for your SSR? and I am sure we can solve this or find an alternative solution..