CY545 Stepper System Controller
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© 2002 Cybernetic Micro Systems
Chapter 16 - Timing and Control
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commands between jog steps, providing jog motion and command execution at the same time!
However, the Jog signal is ignored while these commands are executing.
While jogging, the CY545 will use a step rate derived from the parameter of the First Rate
command. The normal initial stepping rate for continuous motions is taken from the First Rate
parameter value, and this rate is divided by 20. Note that the same step rate is used by the
Home command. The CY545 Step Rate Table lists the step rates for continuous motion. These
rates should be divided by 20 to obtain the jogging step rate. With a 12 MHz clock, jog rates
from about 1 step per second to about 1000 steps per second are possible.
The CY545 will not accelerate or decelerate during jogging, running only at the rate derived
from the current value of the First Rate parameter. However, the interactive command execution
during jogging does allow you to modify the step rate, by issuing a First Rate command with a
new parameter value.
Automatic Position Display
Also, when bit 4 of the Mode Register is set, the CY545 will display the current position at the
end of every jog or Home command step. The position is output to the currently enabled display
device, and will affect the step rate. For example, sending the current position to a serial device
would require enough time to issue the 11 character position string at the baud rate defined for
the serial interface.
The JOG signal also represents a minimal mechanism for testing the CY545 and motor
subsystem. Without any commands, it is possible to move the motor in either direction, verifying
that the PULSE and CCW signals are correctly connected to the motor power driver, and that
the motor is properly connected. This also verifies that the CY545 is functioning at least in a
very basic fashion.
Home Signal
The CY545 supports an additional stepping function, but it uses the user selectable function
signals to implement the process. This function is the automatic home sensor seek, and is
selected by the Home command.
A single argument to the Home command specifies which user selectable bit or bits to monitor
during the step to home. The parameter value is treated the same as for the Til and Wait
commands, and is reproduced below:
00H to 07H
Test one of user bits 0 to 7 for 1
08H to 0FH
Test one of data bus bits 0 to 7 for 1
10H to 17H
Test one of user bits 0 to 7 for 0
18H to 1FH
Test one of data bus bits 0 to 7 for 0
80H to 0BFH
Test user bits 0 to 5 for a group match
You have the option of checking any one signal for the home sensor, or using the six-signal
group of user bits 0 to 5. Normally, a single home sensor would be connected to a single user
bit signal.
This command uses the same step rate as the jog function described above, a division by 20 of
the step rate selected by the First Rate parameter value, so the CY545 will step the motor at
about 1 to 1000 steps per second while seeking the home sensor signal.
