I'm looking to trigger data acquisition with a 9188 chassis, but the device I want to use to send the trigger pulse (servo drive) operates at 24V. Will this damage the chassis? Should I step the voltage down to TTL level?
You really should read through the specification of the chassis. If you are using a PFI on the chassis, then it can accept up to 25V without damaging the chassis.
There are only two ways to tell somebody thanks: Kudos and Marked Solutions Unofficial Forum Rules and Guidelines "Not that we are sufficient in ourselves to claim anything as coming from us, but our sufficiency is from God" - 2 Corinthians 3:5