Micrologix 1500 won't keep communication settings

[CeeDee]

I'm working with a Micrologix 1500 (1764-28BXB)on a machine and I was trying to get it to talk to a panelview 300 micro (2711-M3A19L1) directly (via 1761-CBL-HM02). After discovering the 1500 was configured for DF1 and wouldn't talk to the panelview, I managed to change the communication to DH485 within rslogix500 and download this change into the PLC. After doing this all was happy in the world and I got the 612 network node error to go away on the screen and the panelview working just fine; reading my I/Os perfectly. As soon as main power was cycled (power off then back on) to the 1500 and panelview the communication link was lost and the 612 network node error showed up again. I don't know what could be causing this. I haven't looked yet, but I suspect it reverted back to the DF1 protocol again. Why? What am I doing wrong? I haven't worked with 1500s very much. I'm used to working with the SLCs and I've never had this problem before.

 

[Mickey]

Does it have a memory module not yet updated to the new settings?

 

[CeeDee]

Yes it does actually have a memory module installed on it. I'm not sure what type yet. I'll be at work in a little bit to find out. Does it matter what type of memory module (RTC or not)? Do I even need the memory module? Is it just defaulting to the memory module upon power up and not the cpu memory? All this was installed way before my time here. I wouldn't even know how to update just the memory module.

Thanks.

 

[geniusintraining]

The memory module may have a different setting so you will need to make changes to it, if you do not then once the power is shut off and restored then it will load the program that is in the eeprom (memory module) back into the CPU and your changes will not be there, unless you download them to the CPU again... sounds like you just need to save the program to the memory module after you make your changes

 

[CeeDee]

I'm not sure yet how to save the program to just the memory module. I have to play with it a bit. The 1500 manual doesn't really tell me much, other than a memory module exists. Could I just remove the module and run the PLC without it? Or is it a simple setting within rslogix?

 

[Bering C Sparky]

Here is another thread that is similar to your situation.
See if it helps you any.

http://www.plctalk.net/qanda/showthread.php?t=38748

Good luck
BCS

 

[Mickey]

Could I just remove the module and run the PLC without it?

Yes.

And if you do, don't forget to change the memory module status bit if set. See picture

 

[CeeDee]

oooh, never thought to look in there. Duh! I should have known to try that. It could have been the end-of-day pressure that took its toll on me. Unfortunately I got too busy with other stuff today I didn't have time to tinker with it. I will surely try these tips next week.
Thanks a bunch, you 3 are awesome!

 

[CeeDee]

sharing victory

Just wanted to share that it worked. I managed to establish and maintain DH485 communication between the PV300micro and the Micrologix 1500 with your suggestions. Thanks again.


S:5/8 and S:1/11 on the Mem module tab was set high. I don't know why exactly. All I did was flash the EEPROM, as suggested, keeping the same settings; Loads from the memory module all the time.

My last question on this matter is: Is this the "right" way to do things? Doesn't this always overwrite the data tables? What is the typical, suggested/ideal way to use this memory module setup?

 

[geniusintraining]

Glad it worked for you

Just depends... there is no "right way" the person that set this up had a reason, I do programming for customers using memory modules, they will ship the mod to me or I will load a spare, then they do not need the software, PC or anything... they just power down the CPU, install the new module and power back up and with the bit set to high their CPU will read the new program and they are up and running with their changes

This is good for smaller companies that do not have or need much support, they do not have to fly in anyone and it saves them a boat load of money and works great for small changes