Intelligent Motion Systems IB S Series, Руководство по эксплуатации

Страница: 14 / 81

12
and half step (alternately one phase energized/ two phases energized).
A common on-board oscillator drives the dual chopper. It supplies pulses
which set two flip-flops. When the current in a winding reaches the
programmed peak value a corresponding comparator resets its flip-flop,
shutting down the output stage until the next oscillator pulse comes along.
Because the windings in the motor store energy, current will continue to
flow through the windings during the off period. The peak current for
both windings is programmed by the current adjust input.
The output stage consists of dual full bridge drivers. The IB Series drives
can be disabled by a logic HIGH signal on the enable input. Ultra fast
recovery fly-back rectifiers are used to improve efficiency and help reduce
noise.
O u t p u t W a v e S e q u e n c e s
The IB series drives generate phase sequences for normal, wave and half step
modes. The state diagram and output waveforms are shown below. In all
modes, the transition occurs on the falling edge of the step clock signal.
N o r m a l M o d e
In normal drive mode two phases are energized at all times. This mode is
enabled by a logic HIGH on the Half/Full step input when the IB drive
initializes to state 1.
W a v e M o d e
In wave drive mode one phase is energized at a time. This mode is enabled
by selecting full step mode when the IB drive is in an even numbered state.
Figure 1.2.2: Normal Mode Phase Sequence
1
3 5
7
2
4
6
8
1 3 5 7 1 3 5 7 1
STEP CLOCK
PHASE A
PHASE B
PHASE A
PHASE B