PLC5 Printer Module

Our printer went out and after installing the new one it's printing gibberish. I'm being told by the AB that there's a baud rate problem.

I've never connected to or modified a peripherals module before. If anyone could assist me in connecting and programming the module i'd appriciate it.

I did look in the main program and didn't find anything for the peripheral module. I don't know if you need to connect directly to the module or if i'm not looking in the right place in the program.

Thanks,
Boe

Welcome to the Forum !

Do you know the part number of the module ? This might be a 1771-DB Series A or B (they're quite different) or a two-slot 2760-RB, or something else.

I presume this is a serial connection to the printer.

If I were diagnosing this, I would connect a terminal program to the printer module and start testing different baud rates and framing (data bits, stop bits, parity) until I saw printer data that looked correct.

Thanks for the welcome...

I don't know the number of the module. It'a a single slot with the printer/peripheral connection port and a programming connection port.

Would I use a hyperterminal for this?

The "printer module" is probably a 1771-DB, then.

The Series A had a round battery hatch on top, a big octagon A-B logo, and two DB25 serial channels. The Series B have two DB25's and an RJ45 connector. Both have an array of LEDs for status at the top.

The part number of the module ought to be on the bottom of its face. This might also be a Prosoft module or some other third party module.

Hyperterminal is an OK program for serial work, but I don't like the difficulty of getting to the serial settings or the very limited display options. I prefer TeraTerm or RealTerm (both free).

Since you are unfamiliar with this serial module, I would approach troubleshooting from the printer and serial output side. See if you can find records or manuals that will let you determine the serial format the original printer was supposed to use.

Is the new printer identical to the old one ? Can you post details about the physical connection and the configuration of the printer ?

I just got back from looking at the default printer settings. It is a Epson LX-300+ II. Unfortunately the old one has a malfunction and I cannot print it's settings. I have tried to reduce the baud from default of 19200 to 9600 and even as low as 4800. At the lower baud rates it won't even print.

I was able to find this:
http://files.support.epson.com/pdf/lx300p/lx300ptg.pdf

It shows the default settings of the 300+. The original printer was the exact same model. I can hook up the original and it tries to print correctly before erroring out. Thus it has to be a setting on the new printer causing my gibberish.

If you could take a look at that pdf and let me know if anything stands out that i should change. "Parallel IF" and "Packet Mode" are things i'm going to try and change next.

Thanks for the assistance thus far... hope this new info helps.

Only one data rate is correct; the PLC-5 module is certainly set for a specific speed and the printer needs to match.

A mis-matched data rate sometimes results in "gibberish". If you're looking at the data in hexadecimal mode you usually see "0xFF" and "0xEF" and other bytes that are mostly 1's if the data rate is mismatched.

Mis-matched parity, numbers of data bits, numbers of stop bits... all of these framing issues could result in "gibberish".

And of course we're dealing with a printer, where it's not necessarily using ordinary ASCII, but might be using an unusual character set.

Definitely set the I/F mode to Serial; I've never seen a parallel printer module on a PLC-5 ever. Could you get a photograph or more details about how the ports and LED's look ?

I was able to get the old printer into it's diagnostic mode. I just had to block some of it's movements to prevent it from getting over to far. Seems it's malfunction is knowing where the printer head is located.

I found that it was set to "9600" baud rate, it's characters were "Roman 8," and it was set for "serial" IF. All other options ie: parity, software, etc matched. Unfortunately we won't run that system again until Monday. This should correct the issues though. I'll keep you posted if there's anything further.

Thanks for the help thus far... I'm glad I came across this site.

Just FYI... The printer is now working.

Thanks for all the help/info.