User's Manual

PMAC User Manual
x Table of Contents
Calculation of Subsequent Moves.....................................................................................................................214
Implications of Calculating Ahead ...................................................................................................................216
SYNCHRONIZING PMAC TO EXTERNAL EVENTS .....................................................................................219
Features to Help Synchronize Motion...................................................................................................................219
Position Following (Electronic Gearing)...............................................................................................................219
Position Following I-Variables ........................................................................................................................219
Changing Ratios on the Fly ..............................................................................................................................220
Superimposing Following on Programmed Moves...........................................................................................220
Time-Base Control (Electronic Cams) ..................................................................................................................220
What Is Time-Base Control?.............................................................................................................................220
Real-Time Input Frequency ..............................................................................................................................221
Constraints on Selection of RTIF......................................................................................................................221
How It Works ....................................................................................................................................................222
Instructions for Using an External Time-Base Signal ......................................................................................222
Time-Base Example ..........................................................................................................................................224
Triggered Time Base.............................................................................................................................................225
Instructions for the Triggered Time-Base.........................................................................................................226
Triggered Time-Base Example .........................................................................................................................226
Set up and Definitions.......................................................................................................................................227
Motion Program ...............................................................................................................................................227
PLC Program ...................................................................................................................................................227
Synchronizing PMAC to Other PMACs ...............................................................................................................228
Clock Timing.....................................................................................................................................................228
Sharing Clock Signals.......................................................................................................................................228
Connections ......................................................................................................................................................228
External Time Base...........................................................................................................................................229
Motion Program Timing...................................................................................................................................229
Minimizing Initial Offset...................................................................................................................................229
Position-Capture Functions ...................................................................................................................................230
Setting the Trigger Condition ...........................................................................................................................230
Using for Homing .............................................................................................................................................230
Using in User Program ....................................................................................................................................230
Offset from Motor Position...............................................................................................................................230
Position-Compare Functions .................................................................................................................................231
Required M-Variables ......................................................................................................................................231
Preloading the Compare Position ....................................................................................................................231
Offset from Motor Position...............................................................................................................................232
Synchronous M-Variable Assignment ..................................................................................................................232
WRITING A PLC PROGRAM..............................................................................................................................233
PLC Programs .......................................................................................................................................................233
When to Use......................................................................................................................................................233
Common Uses ...................................................................................................................................................233
32 PLC Programs ..................................................................................................................................................233
Entering a PLC Program..................................................................................................................................233
Opening the Buffer............................................................................................................................................234
Downloading the Program ...............................................................................................................................234
Closing the Buffer .............................................................................................................................................234
Erasing the Program ........................................................................................................................................234
PLC Program Structure .........................................................................................................................................235
Calculation Statements .....................................................................................................................................235
Conditional Statements.....................................................................................................................................235
Level-Triggered Conditions..............................................................................................................................235
Edge-Triggered Conditions ..............................................................................................................................235
WHILE Loops ...................................................................................................................................................236
Precise Timing..................................................................................................................................................237