Unit - Vexta EMP400 Series Operating Manual

8 Program command

UNIT

Name
Valid mode
Syntax
Function
Request
Depending on the setting in the D command, the motor may rotate more than you had expected,
Warning
causing a dangerous situation. When setting is performed with a UNIT command, always change (or
check) the settings in the D command. The same goes for the OFS command.
Setting the movement-amount unit
For a positioning operation, the unit for the movement amount can be set to the movement distance
or the rotational angle of the motor. By configuring the movement-amount unit, the movement amount
can be set not only in pulses but in movement distance or in angles, making it easier to set the
movement amount. Changing the movement-amount unit does not affect the operating speed.
When changing the movement-amount unit, the movement
amount per pulse (unit value) must be calculated first.
The calculated unit value will be set with the UNIT
command.
Movement unit and movement amount
By configuring with the UNIT command, the number of pulse outputs changes as shown below:
Unit value = 1, Number of divisions = 1
Unit value = 0.01, Number of divisions = 1
Unit value = 0.01, Number of divisions = 50
Formula: Number of pulse outputs = (D/n1) x n2
Note
When configured with a UNIT command, the number of fractional digits for the movement amount
used in the D command will be the same as the number of fractional digits of the unit value.
Example: When the unit value is 0.1, the movement amount can be set to xxx.x (1 digit after the
decimal point) in a D command.
Example: When the unit value is 0.01, the movement amount can be set to xxx.xx (2 digits after the
decimal point) in a D command.
Example) Performing angular unit setting for a geared motor
Motor: 5-phase stepping motor (500 pulses per revolution)
Gear ratio: 50
Number of step angle divisions: 4 (= n2)
8-46
Unit value=
Set the unit of movement amount
Direct input/program
UNIT(1 | 2)[, | ]n1[, | ]n2
Parameter
(1 | 2) Axis
n1 Movement amount per 0.0001 to 9.9999 (The number obtained by
pulse (unit value)
n2 Number of step angle
divisions
Sets the unit of movement amount.
Also sets the number of step angle divisions to support micro-step. Always set this parameter
when using a driver that supports micro-step.
0>UNIT1
0: UNIT1 = 1,1
360°
=0.0144° (=n1)
500×50
Data range
1 (select axis 1), 2 (select axis 2)
∗ If this parameter is omitted, axis 1 will be
selected.
dividing the movement amount per revolution
by the number of pulses per revolution∗)
1.0 to 255.0 (supports micro-step)
∗ The value when the division of step angle is 1
Unit value＝
* The value when the division of step angle is 1
1,000 pulses will be output with D 1000
100,000 pulses will be output with D 1000
5,000,000 pulses will be output with D 1000
Default
1
1.0
Movement amount per motor revolution
Number of pulses per motor revolution∗