If the rise time you are seeing is longer than desired, you have two options: use a stronger pull-up resistor (smaller resistance) in your external circuit, or if you have a PXIe-6556 configure it to use the onboard feature Active Load as an internal strong pull up on the line.
The Active Load feature is specific to the PXIe-6556 only, and this feature acts as a load on the line that either sources or sinks current to a programmable commutating voltage that the user selects. When the line voltage is below this commutating voltage line, Active Load sources current to increase voltage. When the line voltage is above the commutating voltage line, Active Load sinks current to decrease voltage.
To use Active Load as an internal strong pull-up on the line, you will need to configure the following properties:
- Active Load
- Commutating Voltage
- Current Range (Active Load can source/sink at maximum 24 mA, minimum 1.5 mA).