OD_60A8_00 SI Unit Position

Function

This object contains the position unit.

Object description


Index	60A8_h
Object name	SI Unit Position
Object Code	VARIABLE
Data type	UNSIGNED32
Savable	yes, category: application
Access	read / write
PDO mapping	no

Description

Object 60A8_h contains:

Bits 16 to 23: The position unit
Bits 24 to 31: The exponent of a power of ten

Units of the international unit system (SI) as well as a number of specific units are supported. It is also possible to specify a power of ten as a factor.

Listed in the following table are all supported units for the position and their values. Depending on the unit that is used, feed constant (6092_h) and/or gear ratio (6091_h) are/is taken into account.


Name	Unit symbol	Value	6091_h	6092_h	Description
meter	m	01_h	yes	yes	Meter
inch	in	C1_h	yes	yes	Inch (=0.0254 m)
foot	ft	C2_h	yes	yes	Foot (=0.3048 m)
grade	g	40_h	yes	no	Gradian (unit of angle, 400 corresponds to 360°)
radian	rad	10_h	yes	no	Radian
degree	°	41_h	yes	no	Degrees
arcminute	'	42_h	yes	no	Arcminute (60'=1°)
arcsecond	''	43_h	yes	no	Arcsecond (60''=1')
mechanical revolution		B4_h	yes	no	Revolution
encoder increment		B5_h	no	no	Encoder increments. Dependent on the used sensor (encoder/Hall sensor) and control mode. In open loop and sensorless mode, the number of pole pairs (2030_h) multiplied by 65536 corresponds to one motor revolution.
step		AC_h	no	no	Steps. With 2-phase stepper motors, the number of pole pairs multiplied by 4 is equivalent to one revolution. With 3-phase BLDC motors, the number of pole pairs multiplied by 6 is equivalent to one revolution.
electrical pole		C0_h	no	no	Electric poles. With a stepper motor that has, e.g., 50 pole pairs, the unit corresponds to 1/50 of a revolution.
dimensionless		00_h	yes	yes	Dimensionless length unit

Listed in the following table are the possible exponents and their values:


Factor	Exponent	Value
10⁶	6	06_h
10⁵	5	05_h
...	...	...
10¹	1	01_h
10⁰	0	00_h
10^-1	-1	FF_h
...	..	...
10^-5	-5	FB_h
10^-6	-6	FA_h


Example
	If 60A8_h is written with the value "FF410000_h" (bits 16-23=41_h and bits 24-31=FF_h), the unit is set to tenths of degree (factory setting).
	With a relative target position (607A_h) of 3600, the motor moves exactly one mechanical revolution, if gear ratio is 1:1. The feed constant plays no role in this case.


Example
	If 60A8_h is written with the value "FD010000_h" (bits 16-23=01_h and bits 24-31=FD_h(=-3)), the unit is set to millimeter.
	With a relative target position (607A_h) of 1, the motor moves exactly one mechanical revolution, if gear ratio and feed constant are 1:1. If the feed constant is set according to the lead screw pitch of a linear axis, the motor turns far enough that a feed of 1 mm is achieved.