Control Techniques SM-Encoder Output Plus, Руководство пользователя

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SM-Encoder Plus & SM-Encoder Output Plus User Guide
www.controltechniques.com Issue: 4
6 Parameters
6.1 Introduction
The parameters listed in this chapter are used for programming and monitoring the SM-
Encoder Plus and SM-Encoder Output Plus
The SM-Encoder Plus and SM-Encoder Output Plus are classed as dumb modules as
they do not have their own processors, and as a result all parameters are updated by
the drive processor.
The SM-Encoder Plus and SM-Encoder Output Plus parameters are read/written by the
drive background task or at the combined update time for time critical parameters. The
combined update time depends on the number and type of dumb modules fitted to the
drive. For each dumb module the update rate of these parameters is specified as either
4 or 8ms. The combined update time is the total of the update times for all dumb
modules fitted. (E.g. if two modules with 4ms and 8ms update times are fitted to the
drive, then the combined update time for the time critical parameters of each module will
be 12ms.)
Some functions with the SM-Encoder Plus or SM-Encoder Output Plus modules do not
function correctly if the update time is too long. The input frequency should not exceed
500kHz, but in addition the number of encoder counts seen over one sample period
should not exceed 32768. Provided the frequency is within the 500kHz limit, the
maximum count cannot be exceeded with Fd and Fr encoders with any sample time, or
with Ab encoders if the sample time is 16ms or less. If the sample time is 20ms then the
maximum allowed frequency with Ab encoders is 409.6kHz.
Position/speed feedback update rate
If the module is selected for motor control position feedback then the position and speed
parameters are updated as defined with each parameter, but are available within the
drive at a faster rate as shown below.
If the module is not selected for motor control position feedback the position and speed
are updated as defined with the appropriate parameters.
Dumb module Update time
SM-I/O Plus 8ms
SM-Encoder Plus 4ms
SM-Encoder Output Plus 4ms
SM-Resolver 4ms
Control position Current controller sample rate
Control speed 250us
Position controller position (menu 13) 4ms
Position for SM-Applications module, etc. 250us
The same parameter structure is available in menu 15, 16 and 17 referring to slots 1, 2
and 3.
NOTE