Internet PLC Forum

General => Technical support => Topic started by: Jaime on January 06, 2005, 09:44:49 AM

Title: PLC's Program Failed Checksum test
Post by: Jaime on January 06, 2005, 09:44:49 AM

HI, I have a T100MD1616+ PLC  and work without problems for one year. But now I  can't  make On-line monitoring. Following message is show : "PLC's Program Failed Checksum test" and, obviusly program don't run. It's EEPROM wrong? Can i change them? Please I need you help,

Thanks

Jaime

Title: Re:PLC's Program Failed Checksum test
Post by: support on January 07, 2005, 01:26:11 AM

You mean you still get the "PLC program failed checksum" message? It seems like you are getting communication with the PLC. Can you try to communicate via TLServer and see if you get a response for "IR*" command. If so, the CPU is still alive.  You can try to turn ON DIP switch #4 and then reset the PLC. Set baud rate to 9600 bps and then transfer a blank program to the PLC. Then OFF DIP switch #4, reset PLC again and set baud rate back to 38400. This may rescue corrupted EEPROM. If it gets back to life then re-transfer you program to the PLC and it should work again.

If not, you may contact us at support@tri-plc.com and arrange to buy spare EEPROM.

Title: Re:PLC's Program Failed Checksum test
Post by: jaime on January 07, 2005, 05:28:38 AM

Thanks for your answers, but previus to post here  I do all that. I can comunicate with DIP SW#4 ON and transfer programs, but when I return to normal operation mode, PLC sent me message of Checksum Test. I'm using TL4 software  to program and I can send Command too. Now I  guest EEPRON chip has the problem and need to know where I could adquire it.  

JG

Title: Re:PLC's Program Failed Checksum test
Post by: support on January 09, 2005, 11:28:01 PM

Our sales department will handle your request directly via email.

Title: Re:PLC's Program Failed Checksum test
Post by: cdenk on August 29, 2006, 09:04:19 AM

If the EEPROM goes bad, is just the memory locations that have been written to too many times,  and by moving somewhere else, the EEPROM is still useable, or needs replacement?

Is the checksum error the usual (only) defective symptom?

The 100,000 number applies to both program and data (SAVE_EEP) areas.

The EEPROM can have a bad data area, but sill be useable in the program area?

Title: Re:PLC's Program Failed Checksum test
Post by: support on August 29, 2006, 10:32:33 AM

Checksum only check the program code, not the data space. In fact checksum doesn't even include the timer and counter set value since these can be changed externally by the users.

EEPROM can be damaged when there is a high energy pulse surge through the power supply.  It is less often worn out due to overuse.