User-defined units
The controller offers you the possibility to set user-defined units. It is thereby possible to set and read out the corresponding parameters, e.g., directly in degrees [°], millimeter [mm], etc.
Depending on the mechanical circumstances, you can also define a Gear ratio and/or a Feed constant.
Value changes of all objects that are described in this chapter are not immediately applied in the Operation enabled state of the CiA 402 Power State Machine. For this to happen, the Operation enabled state must be exited.
Units
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 for 60A8h (Position unit) or 60A9h (Speed unit). Depending on the unit that is used, Feed constant (6092h) and/or Gear ratio (6091h) are/is taken into account.
Name | Unit symbol | Value | 6091h | 6092h | Description |
---|---|---|---|---|---|
meter | m | 01h | yes | yes | Meter |
inch | in | C1h | yes | yes | Inch (=0.0254 m) |
foot | ft | C2h | yes | yes | Foot (=0.3048 m) |
grade | g | 40h | yes | no | Gradian (unit of angle, 400 corresponds to 360°) |
radian | rad | 10h | yes | no | Radian |
degree | ° | 41h | yes | no | Degrees |
arcminute | ' | 42h | yes | no | Arcminute (60'=1°) |
arcsecond | '' | 43h | yes | no | Arcsecond (60''=1') |
mechanical revolution | B4h | yes | no | Revolution | |
encoder increment | B5h | 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 (2030h) multiplied by 65536 corresponds to one motor revolution. | |
step | ACh | no | no | Steps. With 2-phase stepper motors, the number of pole pairs (2030h) multiplied by 4 is equivalent to one revolution. With 3-phase BLDC motors, the number of pole pairs (2030h) multiplied by 6 is equivalent to one revolution. | |
electrical pole | C0h | no | no | Electric poles. With a stepper motor that has, e.g., 50 pole pairs (2030h), the unit corresponds to 1/50 of a revolution. | |
dimensionless | 00h | yes | yes | Dimensionless length unit |
Listed in the following table are all supported units for the time and their values for 60A9h (Speed unit):
Name | Unit symbol | Value | Description |
---|---|---|---|
second | s | 03h | Second |
minute | min | 47h | Minute |
hour | h | 48h | Hour |
day | d | 49h | Day |
year | a | 4Ah | Year (=365.25 days) |
Listed in the following table are the possible exponents and their values for 60A8h (Position unit) and 60A9h (Speed unit):
Factor | Exponent | Value |
---|---|---|
106 | 6 | 06h |
105 | 5 | 05h |
... | ... | ... |
101 | 1 | 01h |
100 | 0 | 00h |
10-1 | -1 | FFh |
... | .. | ... |
10-5 | -5 | FBh |
10-6 | -6 | FAh |
Encoder resolution
Gear ratio
Feed constant
The feed constant is calculated in user-defined position units from the feed (60E9h (Feed) per revolution of the output shaft (60EEh (Driving Shaft Revolutions).
The feed constant is useful for specifying the lead screw pitch for a linear axis and is used if the unit is based on length dimensions or if it is dimensionless.
Calculation formulas for user units
Position unit
Object 60A8h contains:
- Bits 16 to 23: The position unit (see chapter Units)
- Bits 24 to 31: The exponent of a power of ten (see chapter Units)
Example |
|
If 60A8h is written with the value "FF410000h" (bits 16-23=41h and bits 24-31=FFh), the unit is set to tenths of degree (factory setting). | |
With a relative target position (607Ah) 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 60A8h is written with the value "FD010000h" (bits 16-23=01h and bits 24-31=FDh(=-3)), the unit is set to millimeter. | |
With a relative target position (607Ah) of 1, the motor moves exactly one mechanical revolution, if Feed constant and Gear ratio 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. |
Speed unit
Object 60A9h contains:
- Bits 8 to 15: The time unit (see chapter Units)
- Bits 16 to 23: The position unit (see chapter Units)
- Bits 24 to 31: The exponent of a power of ten (see chapter Units)
Example |
|
If 60A9h is written with the value "00B44700h" (bits 8-15=00h, bits 16-23=B4h and bits 24-31=47h), the unit is set to revolutions per minute (factory setting). |
Example |
|
If 60A9h is written with the value "FD010300h" (bits 8-15=FDh(=-3), bits 16-23=01h and bits 24-31=03h), the unit is set to millimeters per second. |
The speed unit in Velocity mode is preset to revolutions per minute. You can only set the unit via the 604Ch Vl Dimension Factor.
Conversion factor for the speed unit
Acceleration unit
The acceleration unit is speed unit per second.
Conversion factor for the acceleration unit
Jerk unit
The jerk unit is Acceleration unit per second.