Using the rs232 ascii functions on an slc5/03

notarealuser

Member
Join Date
Dec 2015
Location
the internet
Posts
4
Hello,

I am an apprentice and ee student and I have been trying get a slc 5/03 to report temperature data and system status history at a fixed time interval into a microcontroller based system for a self learning project.

I have all the data structures setup and functioning properly, and the ascii instructions seem fairly straight forward and capable of doing everything I want them to do.

HOWEVER, when I go to actually do a AWT ascii write, I seem to not be sending data. Even hyperterminal shows no data being sent. I've checked my rs232 settings like stop bits and baud rate.

When I turn on chan 0 system on I get a repeating string of nonsense but when chan 0 is off I get absolutely no rs232 output.

Clearly I'm missing something. Anyone care to throw me some ideas to work with? is there a better method to see what my slc is actually sending out other than hyperterminal?
 
it is worth mentioning that my chan0 system driver is disabled in channel configuration and my chan0 user driver is set for ascii, but my ascii commands are all faulted out with 04.

which means my channel configuration is not set to user.

I'm 99% sure I have all the 'hard' stuff right, and I am missing something blindingly obvious.
 
Welcome to the Forum !

On the General communication setup tab, in the lower Channel 0 section, set the Mode to "User".

Leave the Channel 0 System Mode on DF1 Full Duplex. I think that "Shutdown" disables Channel 0 entirely.

Set the Channel 0 User Mode to ASCII and configure your speed, serial framing, and termination characters.

Now re-examine your repeating string of nonsense. It's probably because of a mismatch in the serial data rate, or the serial framing.

In general when you see mostly 0xFF, it means that the port is transmitting more slowly than you expect, so the UART is seeing mostly 1's.

What sort of microcontroller are you using ? Does it have an internal or external UART ?
 
Also: Ditch Hyperterminal, get yourself RealTerm. Tricky to set up, but it's a real engineering tool while Hyperterminal is a frustrating Windows utility. Ask me how I know it'll silently cut out 1/3 of repeat characters in a binary data stream.

And: If you plan to do a lot of RS-232 work, invest in a Stratus Engineering EZ-Tap. Best value for the money for serial intercept, by a lot.
 
Thanks, you nailed it. So obvious it hurts! I was starting to wonder if the module wasnt defective as s;33/3 was defaulting to 1 even after I factory reset the card before and after I downloaded my program. But presumably s:33/3 is 1 by factory default and in my previous program settings.

I'm still having some kind of issues but I have an output and it is repeatable and of the same structure I intended it to have. So I have my mount molehill for this weekend.

I'm trying to send the data to an arduino mega. It will probably be replaced at some point by something not hilariously cheap, but at that point I will be much more ready to reprogram that part of the project in a more serious language on more serious hardware.

Sometimes I'm all but certain I'm building a Rube Goldberg machine(SLC > Serial > Arduino > TCP/IP > Webserver > Android App. But regardless I enjoy it and I consider it part of becoming a well rounded technical professional. I've really learned alot about how to learn quickly working on this project.

great tip on REALTERM. Thank you very much.
 
And that has to be a good horror story, dealing with the repeating binary stream, do share. Was it on a professional job? I can image some highly uncomfortable hard to explain amounts of downtime before you get to the point where you catch that.
 
Hyperterminal had a strange bug where if you typed the same character three times in a row, the third byte would not be transmitted. It only showed up if you had a corrupted saved configuration file, so it was a bear to find the issue.

And Hyperterminal isn't very good at handling unprintable hex data.

So I use RealTerm. Its GUI is all hacked together and its documentation can be sparse, but I'm confident that when I send and receive hex bytes that I'm getting what I expect.
 

Similar Topics

I have wasted a week trying to figure out how to connect an SLC5/03 with my laptop. I do not have and can not Buy the 1747 UIC and PC3 cables. I...
Replies
14
Views
2,477
We have a third-party rs232 cable, can we connect it to the Rockwell PLC-5/30 and upload the program ? The controller is an Allen Bradley 1785-L30B .
Replies
8
Views
3,939
Hello i am trying to make a connection between my arduino uno and plc delta ss2 using rs232 com1 RTU protocol. The problem here that i did all the...
Replies
0
Views
1,698
I have a Hitachi interface converter Rs232/Rs422 cable that I'm trying to connect a PC to a D100. When i try to connect, it tries for about 30...
Replies
1
Views
1,732
I am trying to communicate from a Micrologix 1400 chan 2 to a SC2124M scanner via modbus rtu. I have taken a straight through cable with RS232 on...
Replies
8
Views
2,743
Back
Top Bottom