Possible problems with firmware difference?

Gents!
I have just replaced a faulted processor SLC 505, 1747-L553 Series C - FW 9 with the exact same CPU except FW 13. It seems to be doing OK at the moment. My concern is that this is on a critical piece of equipment for our operation. If it works from the onset, will it continue to do so or can problems pop up? Thanks in advance for any advice.
Roy

In general, if it runs now it will continue to run.

The usual problems I have when mixing firmware is when I try to go to an older unit; If I tried to replace an FRN11 controller that was using Modbus RTU master with an FRN9 unit that didn't have it, I wouldn't be able to download the program.

While there's still a chance that the newest firmware has a bug or performance difference compared to the older firmware, the SLC-5/05 is such a stable and mature controller that the chances of hardware failure are greater than the chances of a malfunction related to firmware.

Sometimes when you have to replace a controller, you get a lot of "it must be the firmware because we didn't have these problems before you replaced it !" complaints. In my experience, the problems you find after replacing a controller are often related to the damaging event that destroyed the controller in the first place.

Ken Roach said:

Sometimes when you have to replace a controller, you get a lot of "it must be the firmware because we didn't have these problems before you replaced it !" complaints. In my experience, the problems you find after replacing a controller are often related to the damaging event that destroyed the controller in the first place.

Click to expand...

Those are some of my favourite complaints. Right up there with "the PLC seems to be forgetting" complaints and "the code must have changed" complaints

Thanks Ken for the reassurance. That was my thinking but its always nice to have someone with more experience back your gut up.

ASF, one of my favorites is when when one of my mechanics tells me that one of our AB servos with an absolute encoder lost where it was so I had to retime/rehome the entire machine.

Roy

My favorite is “it stopped communicating so the modems must be bad”. Forget the fact that there is a small crater where the PLC used to be because of that 7000VAC power surge.

What, your modem doesn't have a Firewire port? Oh wait...fireBALL...I meant fireball.

No but I did actually have a guy who told me that because we state the modems are “industrial hardened” that they should be able to take a lightning hit without an arrestor (I don’t guarantee they’ll survive with an arrestor). The best one is a guy who had a set of our modems installed in a salt processing plant where he left the panel door open in an area exposed 24/7 to salt dust. After six months the modem failed and when it came back for repair (he didn’t tell us the panel was left open) I found the seven layer PCB delaminated (what was one board was now seven). He threw a hissy fit when I wouldn’t warranty the modem. He shut up when I asked him is AB was going to warranty the PLC and he said no. He got fired (as the service contractor) when the plant operator called us directly to ask why we wouldn’t support our products. Apparently he failed to tell them that he left the panel door open.