Master frequency, standardisation, conversion rpm in controller-internal values

Question:

How can the controller-internal value of a phase difference signal displayed in rpm, e. g. the one of the master frequency input DFIN, be calculated?

Answer:

The phase difference signals (master frequency, variables with '_v' at the end) of the 9300 drive controller and the ECS servo system are displayed in the user-friendly unit 'rpm' via display codes or the diagnostic function in the GDC function editor (e. g. display code C0539 for the input value of the DFSET-IN).
The calculations in the function blocks are not executed in rpm, but in the fix standardisation for phase difference signals in (inc/rev). Consequently, the input values in 'rpm' is modified inside the controller. The corresponding calculation is executed for displaying the phase difference signals in 'rpm'.
Controller-internal phase difference signals always refer to the standardisation 65536 inc/rev (increments per encoder revolution). This information makes it possible to calculate the internal value of the phase difference signal, provided that the speed is known.

Calculation:

• (Speed in rpm) x (65.536 inc/rev) / (60.000 ms/min) = (internal value in inc/ms) or shortened
• (Speed in rpm) x 16384 / 15000 = (internal value in inc/ms)

Example:
Encoder's speed = 4000 rpm
The internal value is calculated as follows: 4000 x 16384 / 15.000 = 4369 inc/ms

Tip:
Under C0425 the DFIN constant (number of encoder pulses per revolution) is entered for the master frequency input DFIN. Independent from this entry the DFIN always shows values in the standardisation 65536 inc/rev!

The following diagram is an overview of the factors for the modified standardisation of phase difference signals and analog values between internal formats and displayed formats.