Yaskawa Modicon 800 Series Remote I/O Network for use on Microtrac LAN - Manual (Page 18)

4 SOFTWARE
17 Sample PLC Ladder Diagram
5/24/96
Figure 6. Sample PLC Ladder Diagram
———————————| |———————————————— PLC_DATA
LOAD_PLC 4xxxx
PLC2DSD
4xxxx
BLKM
00001
DSD2PLC
3xxx
DSD2PLC
3xxx
DSD_OLD – 1
4xxxx – 1
DSD2PLC
CMPR 4xxxx
00001
BLKM
00001
PLC2DSD
4xxxx
DSD_INT
4xxxx
BLKM
00001
DSD2PLC
3xxxx
DSD_OLD
4xxxx
BLKM
00001
ABBREVIATION KEY
DSD_INT = PLC to drive network (output register)
DSD2PLC = drive to the PLC (input register)
DSD_OLD = temporary storage of DSD2PLC for detection of
changes in value
LOAD_PLC = true indicates the value stored in the PLC is to
be transferred to the drive
PLC_DATA = Data to be moved into the PLC2DSD register when
LOAD_PLC bit is true
PLC2DSD = data transfer register from PLC to the drive
RD 3004-20