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Question on DRM021 ACIM V/Hz Control Using 56F80x

Question asked by sandrom on Sep 20, 2017
Latest reply on Sep 27, 2017 by sandrom

Greetings all,


I'm struggling on a old Variable Frequency Drive project with uC 56F8023 (i cannot change micro). For better understand how to develop it, I found a 2002 C example project (from Motorola) that can be created from "CW 8.3 for DSC56800/E" (build 091203).

With it you can create a project from "File => New... => Processor Expert Examples Stationery => DemoApplications => MotorControl => 56F8023 => 3ph_ACIM_VectorControl". 

This project refers (I suppose) to the Designer Reference Manual in subject.


It is a very good point to start from, but I can't found detailed documentation of the code.

Do anybody have some more information about it?


The stuff I can't figure out is at the start of main header file:

/* Application maximum values used for scaling */
/* maximal voltage (dc-bus) measurable by ADC 407.0 V = 100 % */
#define APP_VOLT_MAX 407.0 /* [V] */
/* maximal output frequency of generated sinewaves [Hz] 128.0 Hz = 100 % */
#define APP_OMEGA_MAX 128.0 /* [Hz] */

I understood that the 407.0 depends on HW design (as described in comment), but I don't understand where the 128.0 Hz come from!


Can anyone help me understand this? My big problem is that I don't have the demo board and other HW described in the DRM, so I can't do "reverse engineering" for better understand the example project.


Thanks in advance!