Ladder in yellow color?

[elenercom 1]

HI everybody, I uploaded program from EEPROM-8 of Shilin AX2N-80MR and found out that several parts of program are in yellow color. Could you please tell me what's the matter? Why they are in yellow color like that? Thank you for your kind attention

[Crossbow 294]

The yellow ladder indicates the code in the PLC at that point is not valid ladder. Look at the instruction list to determine what the ladder should look like and make corrections. All it means is that GX Developer cannot understand the instruction list to draw a ladder at that point.

[mikeb 1]

Sometimes NOP instructions can cause that to happen. Look at the program in IL and you may see them.

[elenercom 1]

Thank you for your reply

[provos 0]

Code too long might give the same error.

[FNMdeJong 7]

Look at the instruction list to see if one ladder entry (LD) is not to long. The graphical interface cannot handle to long ladders. Devide long ladders into smaller parts. Mostly seen this when programmed originally in Melsec Medoc or FX-WIN, and uploaded in GX Developer.

[justwhy2003 0]

I have just extracted a program from an A1SJCPU-S3 and it has large sections that are yellow. Some of these sections only have contacts that go nowhere i.e. only connected to the left rung with no coils or instructions attached. When I look at the instruction list there are still sections that say 'Instruction code abnormal' When I uploaded the program there were 2 messages, 1 that 'An error was detected in the parameter data. The data is automatically corrected as a default setting' and 2 that an 'end' instruction was not found and would be added. Does this sound like the program is corrupted? Im hoping that it is a software program only with the possibility of reprogramming from scratch.

[Crossbow 294]

LIke I said earlier in the thread, look at the instruction list and see if you can determine what is being done. There are some things GX Developer has trouble drawing.

[justwhy2003 0]

I know what youre saying crossbow but there are also sections of yellow in the instruction list. The PLC hasnt been in run for a long time, have a funny feeling they switched it off because it wasnt doing what it was supposed to. Best option now maybe to clear the memory and start from scratch. Thanks Justin

[Crossbow 294]

I can honestly say I have never seen yellow in the instruction list. Sounds like there is possible memory corruption.

[justwhy2003 0]

[waynes 8]

This usually happens if the software reading from the PLC doesn't know how to interpret the instruction. I had this the other day whilst trying to upload a FX3U program into GX Dev 6 (very old version). Afaik there was no support for the FX3U in that version.

[RTRBURN 0]

I had same issue with converting a A2N program over to a Q02, it would not do the conversion till the error was fixed. The errors are usually incorrect instruction command. What I did was look at the ladder portion of the error and look at the first ladder before the error and the first ladder after the error, then look at it in the Instruction list then write down the instructions leading up to the error and a few instructions afterwards. Then delete what I had written down then re-enter it but not include the error instruction. Then go back to ladder to check. This is the only way I have been able to get around this. The old programmers, (what looked like a old oscilloscope) is what was used to create these programs in Japan and they would allow incorrect instructions to be written, unlike GX Developer which lets you know that its a no good instruction format. Make sure you back up the program before hand. If you try to delete the yellow section in ladder, in my cases...it would shut down the plc and had to dump the program back into it. Hope this helps.

[Moggie 17]

I had a similar problem - I uploaded the program using GX Developer but the program was originally written with GX IEC Developer The instructions could not be interpreted correctly. Once uploaded with GX IEC Developer there was no errors!

[justwhy2003 0]

Interesting! I know that the PLC was originally installed approx 10 years ago and If I asked a few questions I could probably get in touch with who ever programmed it at that time. I am going back to site today and am hoping to interface a Red Lion modular controller with the PLC via an A1SJ71UC24-R2 RS232 serial link to pull some parameters out for logging purposes. Knowing what the program contained would be handy to know what registers to target for extracting analogue input information. I will also look into extracting the program using GX Dev IEC to see if this makes a difference. Thanks for the feed back, ill let you know how I get on. Justin

[mavbr42 0]

On 07/07/2008 at 11:13 AM, provos said:

Code too long might give the same error.

Absolutely agree