Rainbow Electronics ATA6830 - Manual (Page 9)

9
ATA6830
4575B–BCD–01/03
Power-up Sequence After power-up the circuit has to be synchronized and a reference run has to be exe-
cuted before a position command can be carried out. Figure 9 shows a timing diagram
on how the necessary sequences follow each other.
Figure 9. Power-up Sequence
The first sequence is the synchronization sequence. Its pattern (Figure 6) should be
sent at least 4 times to be sure that the following commands will be recognized. If there
are distortions on the bus it is helpful to send this sequence more than 4 times. A RC
lowpass filter at the bus pin (Figure 16) helps to reduce distortsions.
After synchronization the stepping motor has to make the reference run to initialize its
zero position. The first reference run will only be executed if the circuit recognizes this
command three times in series. This function is implemented contributing to the impor-
tance of the reference run. After the reference run the circuit will switch to normal
operation. To perform a reference run during normal operation, the command has to be
sent only once. Figure 10 shows the state diagram for the implemented sequence
processor.
1 2 4 1
SYNCHRONIZATION
SEQUENCE
2 10
REFERENCE RUN
SEQUENCE
MESSAGE
FRAME
POWER
UP
POSITION 1
POSITION 2