How to Use the Step Ladder Program Block
How to Use the Step Ladder Program Block
The Step Ladder Program block (Block Model 301) is used in the following cases:
Á
When logical operations such as AND, OR and NOT are to be performed on the Loop Control Unit
Á
When input of changes in the contact state (OFF to ON or ON to OFF) are to be converted to one-shot
contact outputs that are ON for only one operation cycle
Á
When system contacts such as constantly ON contacts are to be used on the Loop Control Unit
Á
When step progression control, for example, is to be performed on the Loop Control Unit
Note
When contact signals are simply to be connected between function blocks, the Contact
Distributor block (Block Model 201) is used.
To be more precise, the Step Ladder Program block is used in the following applications:
Á
For setting the conditions for indicating Remote/Local switching
Á
For setting the conditions for indicating Auto/Manual switching
Á
For setting the tracking switch conditions
Á
For setting the MV hold conditions
Á
For setting the PID switching conditions
Á
For setting command switch conditions (e.g. tracking switch, run/stop command to ITEM Setting blocks)
Á
For step progression control of devices
Example
Advanced PID
(block address)
Contact input
One of
• Logic sequence operation
• System contact use
• Step progression control
Step Ladder Program (Block Model 301)
A/M
002-086
R/L
A/M
When PID of block address 002 is set to AUTO and the
mode is the remote mode, MV tracking of the PID of block
address 001 is ON.
Appendix 1
Step Ladder program
(Block Model 301)
002-026
001-085
A/M
MV tracking
Appendix 1
Contact output
Advanced PID
MV
(block address
tracking
001)
205