The "Interpolated Position Mode" was the beginning: With cyclic-synchronous setpoint specification today not only positions can approach coordinated, but also synchronize speeds and torques over several axes in the millisecond cycle. The Servo drive families "Triodrive D / xS" and "Mididrive D / xS"from ESR Pollmeier offer three additional operating modes for the connection via Ethercat or CAN open.
In the interpolated position mode, position actual values are transmitted to the servo drive at regular intervals via the fieldbus, which then finely pol- ishs them to the stroke of the position controller. This means that several axes can be synchronized and exact trajectories can be driven. The drive specialist has been offering this operating mode for many years in its digital servo drives with EtherCAT or CANopen interface.
The real-time capability of the fast fieldbus opens up further possibilities. With the latest generation of servo controllers Triodrive D / xS and Mididrive D / xS, position targets, speeds or torque setpoints can now be transmitted cyclically and synchronously. This makes sense in conjunction with controllers that take over control tasks over several axes. The transmission of the setpoint values as well as optional offset and precontrol values occur at fixed intervals to all drives at the same time, typically all 1 to 4 ms. In this way, motion control applications can be realized in which it depends on the exact interaction of the individual axes.
The operating modes are based on IEC 61800-7-2 as well as on the CAN open profile CiA 402. In the cyclic-synchronous position target specification, intelligent setpoint processing in the servo drive ensures that an "overflow" does not lead to jumps in the movement. This allows endless axes, which only ever position in one direction. Based on the Triodrive D / xS and Mididrive D / xS servo drives, the manufacturer creates individual drive packages in the torque range from 0,5 to 160 Nm - with gears or direct drives even far beyond.