Thanks for the reply Justin. However, the knowledge base entry that you pointed me to seems to be for the AI not the DIO. From the 6009 manual, I know that the 6009 DIO can source up to 8mA with an external pull-up, but I haven't really been able to decipher the sink capability.
The max sink per DIO line may also be 8mA, but I would expect it to be higher (15-25mA).
Hi Justin M,
I know it's been a while (i.e. years) since this thread began; please bear with me...
Page 22 of the USB-6009 manual states that "The default configuration of the NI USB-6008/6009 DIO ports is open collector, allowing 5 V operation, with an onboard 4.7kOhm pull-up resistor."
1. I'm puzzled by this statement. Can this onboard pull-up be disconnected through software or jumpers? If not, then it would seem that the output is not really open collector, but is instead TTL (0V or 5V). In other words, it appears that the USB-6009 digital outputs can not be used to convert from a TTL control signal to a +24V "industrial" control signal?.!