AB Sequencer Problem
AB Sequencer Problem
(OP)
I'm having a problem with an AB Micrologix 1000 program that utilizes a sequencer (SQO) to alternate the operation of a series of lights. I'm fairly new to PLC's, but I understand ladder logic and have been successfully modifying previously-created programs as needed for new applications. I want to revise an existing program that sequences five lights(SQO Length=5) to one that sequences six(SQO Length=6). The original Length 5 program works fine. But in the Length 6 program, the output bit for position six never gets set, so the sixth light is never turned on.
Any suggestions out there?
Any suggestions out there?





RE: AB Sequencer Problem
There are several possible causes to your poblem.
1. SQO moves 16-bit data from one memory location to a word address, do you have the correct word in the source location?
2. SQO has a bit mask feature, perhaps you are masking the 6th bit. Is anything entered in the mask box? If the mask box has a file location instead of a hexidecimal value, you must have a mask word for each index, the mask file indexes with the source file.
3. Is the proper length been set? What is the current value?
RE: AB Sequencer Problem
RE: AB Sequencer Problem
http://www.mrplc.com/cgi-bin/code/filedisplay.cgi?category=machab
It's called PicknPlace Sequencer
Good luck!
Chris
http://www.mrplc.com
Chris Elston
Automation & Controls Engineer
http://www.mrplc.com