OMS MAXnet, User Manual

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SERVICE
MAXnet User’s Manual
7-1
7. SERVICE
7.1. USER SERVICE
The MAXnet family of controllers contain no user serviceable parts.
7.2. THEORY OF OPERATION
The MAXnet controller uses a PowerPC microprocessor for the core of its design. The highest
priority process calculates the desired velocity at the selected update rate with a proprietary
algorithm (patent number 4,734,847). This frequency is written to logic on board which generates
the pulses for stepper motor control and/or the appropriate voltage levels for Servo Control. The
velocity profile and synchronization of each axis is also handled by the PowerPC.
The commands from the host computer are temporarily stored in a character buffer until the
MAXnet can parse them. The command is then executed immediately or routed to separate
command queues for each axis. The command queue contains a list of addresses to execute.
The argument queue stores the parameters (as applicable) supplied with each command for the
axis. A command from the host may be expanded into several commands to the appropriate
axis. The GO command, for example, will expand into start, ramp up, constant velocity and ramp
down commands. The LS command will save its parameter in the argument queue, the loop
count, on a loop stack along with the address of the LS command to be used by the next LE
command as a target for a jump command are stored in the command queue. The LE command
will decrement the loop count and jump to the most recent LS command providing the loop count
has not reached zero. If the loop count has reached zero and it is not nested inside another loop,
the queue space will be flagged as available and the next instruction in the queue will be
executed.
The communication interface is performed by the MAXnet microprocessor.