Yaskawa NS300 - Manual (Page 12)

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 12 of 16
When a set/read command is active (bottom rung), the coil will remain latched as long the
PLC_COMMAND_START bit is held on. When a motion command is active (middle rung), the circuit will remain
latched until the PRGS_FALL bit is set, opening up the normally closed contact. The PRGS_FALL bit is the one-
shot falling edge of the PRGS response bit, shown in line 34 below. The falling edge of the PRGS bit indicates
the NS300/500 has completed the motion profile, and COMMAND_BIT can be removed.
Fig 8. PRGS Falling Edge Circuit
Once COMMAND_BIT is set, ANDing COMMAND_BIT with the selected command sets the specific command
bit. An example of this is shown below. Command bits for feed, step, and station are shown in lines 35 thru 37
(this operation occurs on lines 35 thru 40). When the selected command and COMMAND_BIT are both active,
the coil will be set. This allows one command bit circuit to control all of the commands as well as preventing
multiple commands from being active together. Note that for feed, PLC_COMMAND_START must be active to
set the output. This has been added to provide jog functionality by stopping motion whenever the command is
removed.
Fig 9. Setting Individual Command Bits