To achieve quick response and follow, fast calculation and execution, minimum stop overshoot and stopping time, and 100Hz reciprocating motion for the best performance of warp knitting machine, two EMAC200 controllers were used to control 4 servo motors, with each controlling two. And connect the synchronous bus from the controllers to synchronize the two clocks.
Control Principle and Control Requirements:
(1) The system includes a Master axis. The Master’s current angular position may be acquired from the coaxial connected absolute encoder. The speed of the Master axis is 1,000 to 2,000 rpm.
(2) The system includes 3 to 8 Slave axes. Each Slave turns twice with the Master with in 1 Master rotation (0~360).
(3) Each Slave axis starts its first rotation when the Master axis reaches angle A; and complete the first rotation when the Master axis reaches angle B; then starts the second rotation when Master axis reaches angle C; and complete the second rotation when Master axis reaches angle D.
(4) Each Slave axis corresponds to a different [A, B] and [C, D] angle section on the Master axis. And the angle can be set and adjusted through Ethernet communication on an upper IPC.
(5) As shown, the angle between [A, B] is between 40 and 120; and the angle between [C, D] is between 120 and 180.
(6) Each Slave axis only rotates within its corresponding [A, B] and [C, D] angle range; rotation outside this range is prohibited.
(7) The linear displacement (after conversion) within the [A, B] angle range for each Slave axis is 0-2mm; the linear displacement (after conversion) within the [A, B] angle range for each Slave axis is 0-7mm.
(8) Each linear displacement value for each Slave axis is controlled by the pattern process documents sent by the upper IPC. These pattern process documents are saved in the PLC and require retentive. The length of theses files is up to 32KB.
(9) Regardless of whether the Slave axis is moving, its current location can be manually adjusted.
(10) Regardless of the angle of the Master axis, the slave axis current location can be manually adjusted.
(11) When the Master axis stops, the Slave axes must stop (unless the location is being manually adjusted). The Master axis can stop at any angle position.
(12) When the external power is off, within 30 seconds, the servo drives and servo motors of each Slave axes should be able to function normally with the continuous power supply from the power unit, until the Master axis stops completely.
(13) The load for each Slave axis is 12-15kg.