ASCII instruction error

I'm debugging a AB PLC-5 program and came across an ASCII error that sets bit S:17/8. I've looked through the manual but can't find any details, any ideas?

Using Strings

You can address string lengths by adding a .LEN to any string address (for example, ST17:1.LEN).

String lengths must be between 0 and 82. In general, lengths that are outside of this range cause the processor to set a minor fault (S:17/8) and the instruction is not executed.

Taken from the logix 5 help file

S17/8 is the Ascii Instruction Error bit.

Look in the processor status under the "Prog Warning" tab.

Thank you for replying, this is my first posting on this site so I apologize for not giving more detailed information. I'm trying to fix someone elses program that I'm not sure ever worked right. I've checked all hardware posibilities; serial adapdter card, cables,ext. and everything looks OK. Then I ran across this error in the processor status box. I checked all the string lenths in all the ASCII instructions , and they are all within the 82 bit lenth. Is there anyway to find out exactly which instruction the processor is having a problem with? Or is it possible that there is still a hardware issue. Thank you

You could put in a debug latch after every Ascii instruction, then you can tell what part of the program is setting the error bit.

Something like this:

   S17/8               B3:100/0

---]   [------------( L )---

                     |

                     | S17/8

                      --(U )---



 S17/8               B3:100/1

---]   [------------( L )---

                     |

                     | S17/8

                      --(U )---



 S17/8               B3:100/2

---]   [------------( L )---

                     |

                     | S17/8

                      --(U )---

Wow, you guys have been a great help! I've found the problem and the program is working fine now. Thanks! I'm glad I found this site, I'll be back.