Automating Manufacturing Systems - Process Control and ...

plc advanced functions - 16.7
A
SQO
File #B3:0
Mask 000F
Destination O:000
Control R6:0
Length 4
Position 0
SQO(start,mask,source,destination,control,length) - sequencer output from table to
memory address
SQI(start,mask,source,control,length) - sequencer input from memory address to table
SQL(start,source,control,length) - sequencer load to set up the sequencer parameters
Figure 16.7
The Basic Sequencer Instruction
An example of a sequencer is given in Figure 16.8 for traffic light control. The
light patterns are stored in memory (entered manually by the programmer). These are then
moved out to the output card as the function is activated. The mask (003F =
0000000000111111) is used so that only the 6 least significant bits are changed.