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Chapter 3 - Device Profile
CD1-k – CANopen Communication Profile
3.11 – STEPPER EMULATION MODE
The stepper motor emulation application is only possible for motors equipped with a resolver such as a position
feedback sensor (see object 3070: motor feedback selection). The Pulse and Direction input configuration must
be selected in the Encoder input selection (see object 3080). The Pulse train and the Direction signal are both
generated by the host controller via its stepper motor control interface.
The Stepper emulation mode of operation is selected by setting the value –1 in the object 6060. When Pulse
following control is enabled in the control word, the servo motor position setpoint is recieived via the Pulse and
Direction input pins of the CD1-k amplifier.
3.11.1 - FUNCTIONAL DESCRIPTION
The specific bits of the control word (object 6040) used in stepper emulation mode are described below:
Bit Function
4
Enable pulse following
5 reserved
6 reserved
The specific bits of the status word (object 6041) used in stepper emulation mode are described below:
Bit Function
12
Pulse following OK
13 reserved
When the amplifier is switched on with the stepper emulation mode selected, Pulse following control is disabled. In
this case, the input pulses are not counted and the motor is enabled at standstill.
When bit 4 of the control word (Enable pulse following) is set at 1, the motor starts following the input pulses.
If a pulse train is received by the amplifier when bit 4 of the control word (Enable pulse following) is set at 1, the
motor speed is ramping according to the ramp function (object 604F). When the motor speed value corresponds
to the pulse train frequency, bit 12 of the status word (Pulse following OK) is set at 1. At this moment, the motor
position is locked in phase and frequency with the pulse train. The polarity of the motor speed is given by the logic
state of the Direction input.
When bit 4 of the control word (Enable pulse following) is set at 0 while the motor is running, the motor speed is
ramping to 0 according to the ramp function (object 604F). Bit 12 of the status word (Pulse following OK) is set at
0 as soon has the motor starts braking.
3.11.2 – PARAMETER SETTING
The motor displacement direction with regard to the Direction input logic state can be configured by using bit 5 of
the Polarity parameter (object 607E).
The motor Maximum speed value is calculated according to the host controller pulse frequency limit as follow :
Maximum speed (rpm) = 120 x pulse frequency limit (Hz) / Revolution increments (object 608F sub-index 1)
The Max Motor Speed parameter (object 6080) is set to the previously calculated maximum speed value + 10% to
avoid amplifier speed saturation.
The Revolution increments value (object 608F sub-index 1) for a stepper emulation application is calculated as
follow : Revolution increments = 2 x number of controller pulses for one motor shaft revolution x second sensor
scaling factor (object 306C). The second sensor scaling factor is set at 1 for stepper emulation application.
3.12 – ELECTRONIC GEARING MODE
Electronic gearing allows to synchronize the position of the servo motor with the position of a master axis
according to a given gearing ratio value. The master axis is equipped with a position sensor connected to the
second sensor input of the CD1-k amplifier.
The Electronic gearing mode of operation is selected by setting the value –2 in the object 6060. When Motor
Gearing control is enabled in the control word, the servo motor position setpoint is received via the second sensor
input (encoder or resolver according to the object 3070).