Selecting Units for Your Application
Units are configured independently for each axis on the drive. The WorkBench Units view (accessible from the View Tree under Axis > Settings) helps to select the correct units for the axis mechanics.
There are three primary measures of motion: position, velocity, and acceleration. You must first choose units of measurement for each of these, and then enter the details of the mechanics in order to scale the chosen units appropriately.
The settings for units are automatically applied. The unit settings in the drive will reflect last settings made in the Units screen before exiting. To save settings into the non-volatile memory of the drive, click the Save to Device button in the toolbar.
Type of Mechanics
To set the units in the drive for a particular application, first select the type of mechanics present.
Mechanical Details
Once the chosen units of measurement is selected, the details of the mechanics need to be entered to set the scaling of the chosen units.
In this example, a lead screw with a 10 mm lead and a 5:1 gearbox has been selected. A 10 mm lead means the load will traverse 10 mm for every turn of the screw. A scale factor is applied based on the values entered for the chosen mechanics. This scaling is done through AXIS#.UNIT.PIN and AXIS#.UNIT.POUT , which are automatically adjusted when the mechanics values are entered.
AXIS#.UNIT.PIN is calculated as follows:
10 mm/screw turn * 1 screw turn/5 motor turns = 2 mm/motor turn
Position Units
AXIS#.UNIT.PROTARY sets the position units for rotary motor types.
Rotary Position Units
|
Value |
Units |
|---|---|
|
0 |
counts |
|
1 |
rad |
|
2 |
degs |
|
3 |
|
|
4 |
counts 16-bit |
Linear Position Units
|
Type |
Description |
|---|---|
|
0 |
counts |
|
1 |
Millimeters (mm) |
|
2 |
Micrometers (µm) |
|
3 |
Custom Units (PIN/POUT) per revolution |
|
4 |
counts 16-bit |
Position Range
Min/Max position range depends on the units used.
|
Units |
Min |
Max |
|---|---|---|
|
counts |
-9,007,199,254,740,992 |
9,007,199,254,740,992 |
|
counts 16-bit |
-137,438,953,472 |
137,438,953,472 |
|
rads |
-13,176,794.633 |
13,176,794.633 |
|
degs |
-754,974,720 |
754,974,720 |
|
varies |
varies |
|
|
mm |
-67,108,864 |
67,108,864 |
|
µm |
-67,108,864,000 |
67,108,864,000 |
Velocity Units
AXIS#.UNIT.VROTARY sets the velocity units for rotary motor types.
Rotary Velocity Units
|
Value |
Units |
|---|---|
|
0 |
RPM |
|
1 |
RPS |
|
2 |
deg/s |
|
3 |
(custom units)/s |
|
4 |
rad/s |
Linear Velocity Units
|
Type |
Description |
|---|---|
|
0 |
counts/s |
|
1 |
Millimeters/s (mm/s) |
|
2 |
Micrometers/s (µm/s) |
|
3 |
(custom units)/s |
Velocity Range
Min/Max velocity range depends on the units used.
-
- This limit needs to account for overshoot and velocity ripple. The largest commanded value should be no more than 90% of the velocity limit
|
Units |
Min |
Max |
|---|---|---|
|
RPM |
-30,000 |
30,000 |
|
RPS |
-500 |
500 |
|
deg/s |
-180,000 |
180,000 |
|
varies |
varies |
|
|
counts/s |
-2,147,483,648 |
2,147,483,648 |
|
mm/s |
-16,000 |
16,000 |
| µm/s | -16,000,000 | 16,000,000 |
| Rad/s | -3,141.593 | 3,141.593 |
Acceleration Units
AXIS#.UNIT.ACCROTARY sets the acceleration units for rotary motor types.
Rotary Acceleration Units
| Type | Description |
|---|---|
|
0 |
RPM/s |
|
1 |
RPS/s |
|
2 |
deg/s2 |
|
3 |
(Custom Units)/s2 |
|
4 |
rad/s2 |
Linear Acceleration Units
|
Type |
Description |
|---|---|
|
0 |
counts/s2 |
|
1 |
mm/s2 |
|
2 |
µm/s2 |
|
3 |
(Custom Units)/s2 |
Acceleration Range
Min/Max acceleration range depends on the units used.
|
Units |
Min |
Max |
|---|---|---|
|
RPM/s |
0.224 |
240,000,008.192 |
|
RPS/s |
0.004 | 4,000,000 |
|
deg/s2 |
1.341 | 1,439,999,938.616 |
|
(Custom Units)/s2 |
varies |
varies |
| rad/s2 | 0.023 | 25,132,740.608 |
|
counts/s2 |
16,000,000 | 17,179,869,184,000,000 |
|
mm/s2 |
0.119 | 128,000,000 |
|
µm/s2 |
119.209 | 127,999,999,475.712 |
Custom Units
The drive uses full 32-bit quantization for internal calculations regardless of unit settings. User units settings will not affect performance, resolution, or accuracy of the servo system.
Choose “3-Custom”, and then select your desired position units, for example, millimeters.
Related Parameters
