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. Note: 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 The physical resolution for position measurement of the used encoder/sensor is calculated from the encoder increments (60E6h (Encoder Increments)) per motor revolutions (60EBh (Motor Revolutions)). Gear ratio The gear ratio is calculated from motor revolutions (60E8h (Motor Shaft Revolutions)) per axis rotations (60EDh (Driving Shaft Revolutions)). 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. Described in chapter Assignment of the feedbacks to the control loops is how you can determine which encoder/sensor is to be used for position control and measurement. 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. Described in chapter Assignment of the feedbacks to the control loops is how you can determine which encoder/sensor is to be used for speed control and measurement. Note: 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 You can set an additional factor for the speed unit. Thus, a unit of, e.g., 1/3 revolutions/minute is possible. The factor n is calculated from the factor for numerator (6096h:01h) divided by the factor for denominator (6096h:02h). Acceleration unit The acceleration unit is speed unit per second. Conversion factor for the acceleration unit The factor n for the acceleration unit is calculated from the numerator (6097h:01h) divided by the denominator (6097h:02h). Jerk unit The jerk unit is Acceleration unit per second. Conversion factor for jerk The factor n for the jerk is calculated from the numerator (60A2h:01h) divided by the denominator (60A2h:02h).