"ac torque motors"
If this is controlled by a drive... you might be able to verify that the drive "thinks" it is ready... but that is all!
You can only verify that the drive "THINKS" it is ready!
You will not KNOW that the drive AND MOTOR is really ready... until you, in fact, try it!
"optical interrupter switches"
You CAN NOT absolutely verify these! Unless... you have another sensor that verifies that the Optical Interrupt Sensor is, in fact, where it belongs!
BUT... even then... if the output of a PNP Sensor is shorted to hot... or the input of an NPN Sensor is shorted to ground... you can not KNOW that the sensor is really ready!
You can't KNOW any of this stuff unless you go through the exercise of a real-time simulated run! That is, until you actually send the process into a dry-run to see that the various devices respond as expected!
"tension sensors"
Same as the Optical Interrupt Sensors.
"fiber cutters"
I expect that these are outputs... you need to exercise the device to verify its' action.
"stepper motors"
Same as the AC Torque Motors... All you can do is verify that the Stepper Controller THINKS it is ready! You won't really KNOW, until you try!
"ac variable voltage drives"
Same as the AC Torque Motors and the Stepper Motors.
What you are asking for, in some cases, is absolutely impossible! In other cases, what you are asking for is damned near impossible... without a great deal of built-in support from the manufacturers.
If you want to absolutely verify that all of the devices are ready... you need to run the process through a dry-run. I would call this a dry-run-simulation.
You need to develop a "model" of what should happen.
Then, when you begin the simulation, you need to verify that things unfold as indicated in the "model"!
If so, then all is well.
Otherwise, if something doesn't happen as expected... then post a message indicating that there is a problem with such-n-such.
Your "simulation-model" needs to provide simulated input activity for the various sensors. Those simulated-input activities should be time-based and somewhat (very) similar to real-time product activity. As each step carries on, as expected, keep carrying the "OK" flag forward. However... don't believe that all is "OK" until the simulated sequence is, in fact, completed with the "OK" flag still held high!
Your model has to take into account the possibility of a false-positive!
That is, you need to verify that actual inputs, those affected by your simulated inputs... which drive real outputs, respond AS THEY SHOULD! That includes actual-inputs, which should respond to actual output activity, are going ON AND OFF... WHEN THEY SHOULD!
It is not difficult to build a "model"... you simply have to KNOW YOUR PROCESS!