# AB SLC 503 PLC not able to connect



## MDShunk (Jan 7, 2007)

I have had some SLC's refuse to communicate until I took out the battery, shorted the battery terminals, and reinstalled the battery. Best have a copy of the program, though. With the lack of real serial ports on laptops now, and the dubious nature of most USB to Serial converters, the only cable I've had good luck with was the 1747-UIC cable. ALSO.... Windows 7 royally screwed up a bunch of Rockwell communication stuff. I had an hours long trial the other day just trying to put an IP address in a Flex I/O module with BOOTP, which should rightly take about a minute. Turns out that you need to turn off ALL Windows firewall stuff when doing different communication with older Rockwell software and hardware when you run Windows 7.

EDIT... it runs in my mind that when you program a 5/xx, you can turn off Channel 0 or Channel 1 in the processor configuration. If someone did that, you might try communication on both channels as part of your trial.


----------



## triden (Jun 13, 2012)

A SLC 3 has two serial port, RS485 and a RS232 port. Which port are you trying to connect to? If connecting to the RS232 (db9), make sure you are using a Null Modem cable. Use the auto-configure feature in RSLINX to establish comms.


----------



## Jhellwig (Jun 18, 2014)

Are you using the rj45 port with a pic or are you using the serial port? 

For so reason I have noticed that allen bradley likes to default channel 0 to 19200 baud. Serial communication does not like that. Set it for 9600 when you can manage to communicate to it again. Some usb to serial converters don't like the higher baud.


And if you are using windows 7 like Mdshrunk said you cannot use a pic or whatever the pcmia card is or a 1763-net-aic. You can only use the serial port using a df1 driver in linx or a 1763-net-eni or the device net one.


----------



## RIVETER (Sep 26, 2009)

JPC.CE said:


> I have an old PLC AB SLC 503 for some reason I can not figure out, it will not connect to my software. RSLinx or RS logix 500 tried different cables, drivers etc. have no problem connecting to the other PLCs 500, 501 even no problem connecting to mini PLCs. AB tech not very helpful on this one, they just keep sending me drivers that do not work.


Is there an adapter module in the equation?


----------



## BoulderDay (Jul 22, 2015)

JPC.CE said:


> I have an old PLC AB SLC 503 for some reason I can not figure out, it will not connect to my software. RSLinx or RS logix 500 tried different cables, drivers etc. have no problem connecting to the other PLCs 500, 501 even no problem connecting to mini PLCs. AB tech not very helpful on this one, they just keep sending me drivers that do not work.


Hey Boss... I say we nuke it from orbit. It's the only way to be sure.

SIgned,

You know who


----------

