Memory cassette FX3U-FLROM

[wal]

Hi, we consider a new approach in fixing problems: Instead of sending a maintenance Engineer with a laptop and new PLC program, post the program on a memory cassette(e.g. FX3U-FLROM) with a short manual how to install it. Did somebody try this? Is it safe? What is better, leave the external memory on PLC and run or transfer the program into PLC and then remove it?

[Nightf1y]

Well the easiest way would be to tell them to just plug the eprom in and leave it there. However the advantage of transferring the program into the controller is that you can have your eprom back (not the cheapest of things). Both options work (and I have used them several times). Personally I prefer to leave the eprom in as it is easier for the customer (and PLC batteries are very good but don't actually last forever). Regards Edited August 8, 2014 by Nightf1y

[wal]

Thank You Nightf1y for the answer. What should we avoid to reduce the risk of failure and to encrease the expected lifetime of the memory cassette?

[Crossbow]

You can't increase the life of an EEPROM. It's a fixed number of writes, documented in the manuals. Nothing you can do as far as copying it into a PLC has any effect on its life. I like to use the memory cassettes with the -L on the part number. They have read and write buttons to transfer the program to the PLC. So you can plug it in, test the new program, and if it works, download it from the memory to the controller and get your memory card back. Just remember always add or remove when powered off on FX.

[Theo V]

Hi Wal, Ever thought about using a direct connection trough the internet to your machines instead of sending an EEPROM module? This takes time to arrive on location. I have good results with simple eWon Cosy 141 secure routers. (see: www.ewon.biz ) for more info. It can communicate with Ethernet or serial to your PLC. Best regards, Theo V.

[wal]

Dear Crossbow and Theo V, thank You very much for the answers. After first try to transfer program from memory cassette into PLC noticed, that PLC parameters migrated to default state. So, registers D0..D255 were not latched (as they were set in my project) and that caused problem. What was wrong?

[Crossbow]

When you power up a PLC with a memory module installed, you are running the program (and parameters) which you downloaded to the memory card. When you power up with no memory card, you are running the program (and parameters) inside the PLC itself. My guess is one of the downloads had default parameters set. Remember never add or remove FX memory card under power.

[wal]

Thank You Crossbow, I loaded program and parameters into memory cassette, then made transfer from the the cassette into PLC. After that switched off PLC and removed cassette. After second start, the parameters mismatch was noticed. Is it possible after pressing button on the memory cassette for transferring program and parameters, that parameters are not being transferred into PLC? What is safer, ask service Engineer simply put the cassette into PLC and run, or ask him (her) to transfer program from cassette, then remove it and run without the cassette?

[Crossbow]

I have done this before and it has worked every time. I have CPUs running in the field with memory cards, and have shipped memory cards for customers to update on site without error. I do not know why you are seeing a parameter error. The PLC you are trying to update is not password protected is it?

[wal]

Don't think it is password protected. The PLC was delivered new to our customer in China. Sometimes things happen. Important to know that You tried this solution and it worked. Thank You very much.