slc 500 Problems with serial communication

dms1808

Member
Join Date
Feb 2009
Location
North Carolina
Posts
3
I have an SLC500 1747-L541 running OS401 and I'm having a problem with serial communication once I have completed loading a ladder to it.

RS Linx works fine with out error but once I place the unit in run mode it will not see the serial communication.

Any help would be appreciated.
 
Perhaps your changing the serial ports configuration with the downloaded file. Compare your RSLinx's configuration with the file your downloading.
Tell us how you have RSLinx configured and post your .RSS file and someone can take a look. ( zip it first then post if you can)
 
The interface I am using opens the ladder prior to downloading. I have matched all the parameters I can get to with an operable system. I even pulled a ladder from a known good system.

The problem started when we replaced the CPU.

Is it possible we have a newer version CPU that has closed a port down on me?
 
The interface I am using opens the ladder prior to downloading. I have matched all the parameters I can get to with an operable system. I even pulled a ladder from a known good system.

The problem started when we replaced the CPU.

Is it possible we have a newer version CPU that has closed a port down on me?

No, that doesn't make sence. When you say ver. do you mean a different SLC500 i.e SLC5/03 to SLC5/04 or what please explain.
Are you using the DF1 driver in RSLinx? If so after you download go back to RSLinx and click on autoconfigure.
Again if you can post a snap-shot of RSLinx and post your SLC
code.
 
Last edited:
When troubleshooting configuration problems, posting the actual files rather than screenshots is far more effective. I realize it's not always possible, but since you are a new Forum member (welcome !) I thought I'd mention it.

Why did you change the controller in the first place ? Was the original controller an SLC-5/04, or an SLC-5/03 ? Your answers are not clear on that.

The good news is that there's no firmware revision or hardware change that would shut down the communications port when you enter run mode.

When you download a program to an SLC family controller, the last thing the RSLogix 500 software does is check the Communications channel configurations and compare them to the current settings in RSLinx. If these are different, the software presents a warning letting you know you *may* lose communications on the current or the other channel of the controller.

It is absolutely vital that you pay attention to those messages when they appear.

The label "KF3" on your DF1 Full Duplex driver is unusual. It appears that you might have been using "DF1 to DH+" or "DF1 to DH485" pass-through communications, which requires you to select a different Device Type in your RSLinx DF1 Full Duplex driver, as well as requiring specific Status bit settings in the controller.


Do you recall "going online" with the other DH+ connected controllers while plugged into the serial port of this SLC ?

Check the configuration in RSLinx for the "known good" controller to see what the "Device Type" is. Examine the Processor Status -> Chan.1 tab in RSLogix 500 to see if any of the passthrough configuration bits are set.
 
Does your program use an AWT instruction?

If your SLC's com port is in System Mode, the AWT will still work, but if you are online and teh AWT writes something to the port, it will knock you offline.
 

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