Yaskawa NS300 - Manual (Page 6)

Subject: Technical Note Product: NS300/NS500 Doc#: EM.MCD.05.106
Title: NS300/500 Master Ladder Example
Doc#: Copyright Yaskawa Electric America
©2004
May 9, 2007 Page 6 of 16
Program Flow
The first topic is general program flow. This program has been arranged so that it mimics the structure of the
command message. Three distinct sections of the program have been identified in the table below:
Table 3. Program Sections
Command Message Description Program Lines
Bytes 0-1 General Commands Lines 0-31
Bytes 2-3 Motion Command Bits/
Set/Read Parameter No.
Lines 32-48
Bytes 4-7 Command Data Lines 49-57
Organizing the program in this manner makes the ladder easy to navigate and easy to identify what is being
accomplished at any given line. In addition, an easy to navigate program makes troubleshooting at later dates
much easier. The table below identifies the main tasks to be completed in each section of the program.
Table 4. Program Section Tasks
Program Section Tasks
Lines 00-31
Bytes 0-1 General interlocking – emergency stop, alarm reset, servo
enable
Command identification – set/read (MOD)
Determining and loading the command and response
codes
Lines 32-48
Bytes 2-3 These two bytes are formatted differently for a motion
command versus a set/read command.
Motion command bit sequencing
Setting the proper motion command bit (FEED, HOME,
etc.)
Loading parameter number data for set/read commands
requiring parameter information
Lines 49-57
Bytes 4-7 Load the command data properly for the selected
command (motion or set/read)