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The better and safety way is using one of well-known field busses as EtherCAT for example. You must locate one or more nodes close to your sensors and choose PLC with field bus option as well.

For constant Set-point Output control signal (current/torque command for example) can switch between 3 (+LSB, 0 and -LSB) and even more states. And such finity resolution of Output leads to non-stability of Feedback (encoder) signal is named a Jitter. The Jitter can be more than +/-1 in units of...

Most laser interferometers have - except absolute position output - such output option as standard quadrature RS-422 signal as well.

1. It isn't so important acceleration or velocity you will use because ones differs by operator Laplace only. But how you plan to receive acceleration/velocity step response with quadrature encoder? 2. Cascade structure has PI-filters for current and velocity loops, P-filter for position...

Some questions before advice: 1. Do plant's transfer function is related to velocity-to-current ratio? 2. Do your PID controller has cascade structure with inner current and velocity loops and PI-velocity filter?

For manual tuning of your servo with one sensor you can use recommendation from Galil - one of motion control worldwide leaders http://www.galilmc.com/support/appnotes/optima/note3413.pdf

You must review SOA of your motor from Speed - Torque curve. As a rule a nominal torque is defined as torque at nominal speed. Pay attention that operation outside SOA allowed for short period of time. You must define cont/peak current of servo drive according to motor Spec also.

If you change resolution of feedback sensor, that control loop gain increased accordingly. Except necessity to assign the same actual position value with each transfer, you need to perform "bumpless" control for eliminate any possible spikes with such transfer.

Rated speed is defined with rated or nominal voltage (12, 24, 36, etc) as a rule. Max speed is max allowed speed from mechanical limitation (bearing, coil,etc).

16-bit isn't such used due to high price vs. really commonly used 8 or 10-bit ones. You can use two or more channels for division full range to couple of ranges - with analogue "course" and "fine" ones.

You can use Laplace and inverse Laplace transforms directly. Equation for such simply function are ready and maybe found thro Internet.

The measuring of any loop bandwidth is well-known procedure. I hope that you use one of standard servo amp. Than you need apply harmonic signal with various frequency without current limitation and test current sense signal. You may ask me more with [email protected]

Bandwidth of current loop can be measured at stall rotor location. You may use current monitor existing for each amp for this goal. Position accuracy, repeatability and "in position" stability (position jitter) except scanning position error and move & settle time can be improved with higher...

Better way vs. PLC is motion controller. Than Dual axes DMC controller with build-in servo amps from Galil maybe good choice for you. Simply programming, 2D interpolation and build-in I/Os with extension option - this is exactly you need.

Such 1kHz bandwidth seems very high even without load. What's bandwidth of inner current loop? With application you'll need to decrease bandwidth due to low stiffness between motor and load especially with robot arm usually. In any case high bandwidth of speed loop allows reaching shorter...

If you want check current mode amp, then you need check motor current (from driver's current monitor) vs. current command and not motor speed. Locking motor shaft (i.e. without rotation) can help you get looked transfer function. But you may use simply gain for current loop simulation.

Peter, refer in Internet bandwidth ratio is of course first approach only. For velocity-to-current bandwidth for example it may be higher due to load-to-motor resonances. You may review such definition for one of Elmo servo amps - http://www.elmomc.com/products/cello-main.htm And real...

Recommendation for choosing bandwidth ratio between inner and outer loops you may find thro Internet - see for example http://www.jashaw.com/pid/cascade.html BTW for compensation one time constant inside current loop enough PI-filter and not PID-filter as you wrote. Such PI-filter structure...

You need to use 2nd power model with electromagnetic and electromechanical time constants for synthesis of velocity control with cascaded inner current and outer velocity loops instead such simply model.

Of course closed speed loop with inner current loop will help you. BTW you may use Halls for speed feedback as well. Pay attention on value of PWM frequency also because your motor may have low inductance leading to high current ripple.