Elmo DSP 402 manual 11.3Functional Description

CANopen DSP 402 Implementation Guide

MAN-CAN402IG (Ver. 1.2)

79

Data description:

Value	Description
-32,768…-1	Manufacturer specific
0	Linear ramp (trapezoidal profile)
1	Not supported
2	Not supported
3	Not supported
4…32,767	Reserved

11.3Functional Description

Two different means of applying target positions to a drive are supported by this device profile:

Set of set-points:

After reaching the target position, the drive unit immediately processes the next target position that results in a move in which the velocity of the drive is not normally reduced to zero after achieving a set-point.

Single set-point:

After reaching the target position, the drive unit signals this status to a host computer and then receives a new set-point. After reaching a target position, the velocity is normally reduced to zero before starting a move to the next set-point.

The two modes are controlled by the timing of the bits “new set-point” and “change set immediately” in the controlword, and “set-point acknowledge” in the statusword. These bits allow a request-response mechanism to be set up in order to prepare a set of set-points while another set is still being processed in the drive unit. This minimizes reaction times within a control program on a host computer.

The Elmo drive introduces a buffered mode (bit 13 in the controlword), in which up to 16 subsequent profiled motions can be programmed. The programmed profiles are executed when the previous motion is target reached. In buffered motion, set-point acknowledge behaves in a manner similar to non-buffered mode, whereby the bit is reset when new data can be buffered. Using change set immediately interrupts the buffered motion. In this case, the buffer is reset and the last programmed motion is executed immediately.

The sequence of a set new point is:

1.The host sends the trajectory data and validates it by setting the new set point.

2.The Elmo drive acknowledges reception and buffering of the new data by setting set-point acknowledge.

3.The host sends a command to start the first motion by resetting the new set point.

4.The motion begins. If the drive can accept more set points, the set-point acknowledge resets.