Technosoft iPOS4808 MX Series, Technical Reference

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Technosoft 2014 91 iPOS4808 MX Technical Reference
6. Scaling factors
Technosoft drives work with parameters and variables represented in the drive internal units (IU).
These correspond to various signal types: position, speed, current, voltage, etc. Each type of
signal has its own internal representation in IU and a specific scaling factor. This chapter presents
the drive internal units and their relation with the international standard units (SI).
In order to easily identify them, each internal unit has been named after its associated signal. For
example the
position units are the internal units for position, the speed units are the internal
units for speed, etc.
6.1. Position units
6.1.1. Brushless / DC brushed motor with quadrature encoder on motor
The internal position units are encoder counts. The correspondence with the load position in SI
units
1
is:
] IU [ Position _ Motor
Tr lines _ encoder _ No
] SI [ Position _ Load

 
 

4
2
where:
No_encoder_lines
–
is the rotary encoder number of lines per revolution
Tr
–
transmission ratio between the motor displacement in SI units and load displacement in SI
units
6.1.2. Brushless motor with linear Hall signals
The internal position units are counts. The motor is rotary. The resolution i.e. number of counts per
revolution is programmable as a power of 2 between 512 and 8192. By default it is set at 2048
counts per turn. The correspondence with the load position in SI units is:
For rotary motors: ] IU [ Position _ Motor
Tr resolution
] SI [ Position _ Load


 

2
For linear motors:
Pole_Pitch
Load_Position[SI] = ×Motor_Position[IU]
Tr
where:
resolution
–
is the motor position resolution
Tr
–
transmission ratio between the motor displacement in SI units and load displacement in SI
units
Pole_Pitch
–
is the magnetic pole pitch NN (distance expressed in [m])
1
SI units for position are: [rad] for a rotary movement, [m] for a linear movement