Motion Control Technology
Lynton Manufacturing Service
MODE ‘B’ The Signal Processing Unit
This is the heart of the motion control program.. The functions embedded here form the engine which drives the whole
system. The theory of operation is relatively simple and is based on the equation of linear motion, where the distance covered
is the average velocity x time. Time will be a Constant in the equation from which the distance and velocity are calculated.
An 8253 counter I,C is included on the L.M.S motion control interface board which has been programmed to produce a priority
interrupt every milli-second. This interrupt is the system’s TIME CONSTANT.
When an interrupt is received by the controller 3 primary functions are executed.
1 - The watchdog timer is reloaded. If this timer ever times-out it will shut-down all motor drives and prevent any further
UNCONTROLLED machine moves. The on-screen digital clock is updated as a visual indication that the system is
running correctly.
2 - The Actual Axis Positions are read from the encoder counters and the digital readout display is updated. The encoder
counters themselves are not dependant on this interrupt, they run at a much higher frequency and monitor all axis
positions continually.
3 - A comparison is carried out between the Actual Position (from 2 above) and the calculated position required at this
time period. A voltage Proportional to the difference between these two positions is output to the motor drive
amplifiers. This difference between the ACTUAL and REQUIRED positions is the FOLLOWING ERROR value.
The interrupt routine runs continually, even in MODE ’A’ it runs in the background, looking for any deviation from the current
position, and enables the system to maintain a high positional holding torque. When MODE ‘B’ is initiated by the <F10> key
command, the Edit Screen will change from a Blue to BLACK background and the current program’s instructions will be
processed. To process a move the controller constructs a memory model of the move and records all the calculated positions at
the required velocity every Milli-second (or for every interrupt). Each interrupt then compares the Actual Position against the
recorded model move position thus inducing a FOLLOWING ERROR and a voltage to drive the motor at a speed and distance
equal to the memory model increments.
In order to improve the stability a tachometer is fitted to the motor and the output voltage from the tachometer is INTEGRATED with the PROPORTIONAL following error voltage using a summing amplifier.
This is the heart of the motion control program.. The functions embedded here form the engine which drives the whole
system. The theory of operation is relatively simple and is based on the equation of linear motion, where the distance covered
is the average velocity x time. Time will be a Constant in the equation from which the distance and velocity are calculated.
An 8253 counter I,C is included on the L.M.S motion control interface board which has been programmed to produce a priority
interrupt every milli-
When an interrupt is received by the controller 3 primary functions are executed.
1 -
2 -
positions continually.
3 -
amplifiers. This difference between the ACTUAL and REQUIRED positions is the FOLLOWING ERROR value.
The interrupt routine runs continually, even in MODE ’A’ it runs in the background, looking for any deviation from the current
position, and enables the system to maintain a high positional holding torque. When MODE ‘B’ is initiated by the <F10> key
command, the Edit Screen will change from a Blue to BLACK background and the current program’s instructions will be
processed. To process a move the controller constructs a memory model of the move and records all the calculated positions at
the required velocity every Milli-
equal to the memory model increments.
In order to improve the stability a tachometer is fitted to the motor and the output voltage from the tachometer is INTEGRATED with the PROPORTIONAL following error voltage using a summing amplifier.
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Module 3 The Controller Software
