Communication problem

FKW · Mar 7, 2008

I'm trying to communicate with my Plc. under rslinx when i select auto configure I receive a message " Failed to find the baud and parity!, check all cables and switch setting". I just baught a new cable so im pretty sure that works.

Q1) what are the switch settings
Q2) What are some trouble shotting steps i can take.
Q3) What should the settings be set to, Im using a Rs232 cable, from pc to PLC. it's a micrologix 1200 series C Plc

SNK · Mar 7, 2008

Biggest problem that I see is that the serial port is being used by something else on your PC.
Otherwise, shutdown RSLINX, cycle power on the PLC and re-start RSlinx.
A 1200 doesn't have much to change by switches.
USually just a mini-din connector, sometimes 2 of them.
The PLC MAY be configured for DH-485 connection, in which case you need to change it back to RS-232.

Operaghost · Mar 7, 2008

Ok, RSLinx is giving you a generic message when it cannot connect using auto-configure.

A PLC-5 has dip switches that can effect the serial port. The SLC 500 and Logix5000 do not. Thus the message about switch settings.

As SNK mentions, you have a couple things that could be preventing the auto-config.

The MicroLogix 1200 serial port can be configured to allow you to connect using RS232/DF1 or it could be configured for some other communication protocol and this could be why you cannot connect.
The other main reason is that something on your PC has "taken over" your serial port and thus RSLinx cannot use it.
Maybe it really is a bad cable. Is this a Rockwell cable or one someone constructed themselves?

Do you have an offline copy or a printed copy the file currently running in the Micro? If so, we can look at the configuration of the serial port and see exactly how it is configured.

When you open RSLinx and go to the Configure Drivers window, is anything listed in the Configured Drivers portion of the windows? If so, what?

OG

Bob A. · Mar 7, 2008

I have found that sometimes the serial comm config setup in a software program does not always become the settings that are seen in device manager. It may help to compare the two to identify some confusion.
In other words, the serial config in Linx may not always be real. Also, while you are in device manager, look for serial port related things that are unhappy.

Best Regards,

Bob A.

Chuck Woodbury · Mar 8, 2008

You may also want to check the baud rate on your computer. I tried to connect to a SLC once and found the default baud rate was 1200 or 2400.
This was through changing my computers baud rate and testing the auto configure. Unfortunately, I started on the high side and worked my way down.

Mickey · Mar 8, 2008

1-What cable do you have?
2- Does your PC have a real serial port? Or are you using a USB to Serial adapter. Not all USB to serial adapters work.

FKW · Mar 9, 2008

I'm using a rs 232 cable. on one computer i can hook it up directy, but on my laptop i have an usb to rs 232 adapter. ( im pretty surer the adapter doesn't work because i get a different error message). if i buy a direct usb to rs 232 cable from A-B would that maybe work or should i just stick with plain rs 232 to rs 232. Im really thinking it's the cable now.. unless.. is it possible there might be something wrong with the plc?

thanks for all your help

Mickey · Mar 9, 2008

The best USB to Serial Adapter ( the one that works) is a "Keyspan". It only works with DF1 protocol. You need a real serial port on your PC to use DH485 protocol. Or a AB 1747-UIC ( USB to DH485 converter)
it can be purchased at link below.
http://www.plctrainer.net/

You didn't say what protocol your ML1200's is set to.

FKW · Mar 10, 2008

I have it set to DF1. I have noticed that on the cable, it is listed that the cable is for a micrologix 1000, Ser, A. do they have different cables for different plcs, or is there only one type of cable that works for all microloix plc's?

cciblazer · Mar 10, 2008

Try this thread http://www.plctalk.net/qanda/showthread.php?t=15407

Mickey · Mar 10, 2008

FKW said:
I have it set to DF1. I have noticed that on the cable, it is listed that the cable is for a micrologix 1000, Ser, A. do they have different cables for different plcs, or is there only one type of cable that works for all microloix plc's?

See Picture and PDF below for Cable info

James Mcquade · Mar 10, 2008

if you are using a usb port to talk to the plc, ab has a usb to plc 9 pin serial cable you can buy. i forgot the numberbut its around $75. i have talked to others who used other brands, theirs locked up.

james.

JBJennings · Mar 10, 2008

1747-uic

1747-UIC seems to be the missing part of the equation here.

bobrapp · Mar 10, 2008

FKW said:
I'm trying to communicate with my Plc. under rslinx when i select auto configure I receive a message " Failed to find the baud and parity!, check all cables and switch setting". I just baught a new cable so im pretty sure that works.

Q1) what are the switch settings
Q2) What are some trouble shotting steps i can take.
Q3) What should the settings be set to, Im using a Rs232 cable, from pc to PLC. it's a micrologix 1200 series C Plc

Did you check your DF1 configuraiton? there are several options depending on the device you are connecrting to.

Have you the right cable?

Under the configuraiton, you can change different protocols PLC (PLC5) or SLC/Micrologix for all others.

Good luck,
Bob

FKW · Mar 10, 2008

I'm picking up new cables tomorrow. Mickey those files are corrupt any way i can get a working copy.. Thanks

Communication problem

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