Serial Killer

Sorry, couldn't resist...

Anyhow, I'm trying to marry up a Unitronics M90 with a Yaskawa SGDH servo drive using host commands to initiate indexes and monitor faults, yadda yadda.

Now here's my specific question :

The M90 can do a number of variations on the RS232 protocol, regarding parity and such, but this much is etched in stone: 8 data bits, 1 stop bit.

The Yaskawa's RS232 is pretty inflexible : 1 start bit, 7 data bits (ASCII) and 1 stop bit.

My question is simple - will this combination work? I don't know much about ascii encoding, but I know 1+7=8 (I think), so will it have an effect, or is there a way I can work around the difference in software?

Thanks!

TM

Here's a paragraph from "The C programmers Guide to Serial Communications":

The use of codes smaller then 8 bits brings up an interesting problem. Even though the UART receiver may assemble an SDU of only, say, 5 data bits plus a parity bit, ultimately it must construct an 8-bit byte to output on teh system bus. As we might suppose, the parity bit (if present) is inserted after the most significant data bit. But with what value does the UART fill the unused data bits 6, 7, and 8? Most UART data sheets ignore this questions altogether. In practice, some UART's pad unused bits with 0s, some with 1s and others with random values. In the absence of a standard, therefore, the programmer must assume that unused bits are padded randomly. Accordingly, unused bits should be masked off whenever the combination of data and parity bits is less than 8.

Click to expand...

I don't think there is an easy solution to your problem. But this will probably work: Link to Serial Converter

nOrM

Actually, that's a nogo. There are several companies that make small buffers to take in one framing and re-transmit another framing.
CAP Communication Adapter Plus @ BlackBox.com
Baud Rate and Framing Converter @ B&B Electronics

I was faced in similar problem before few days. I thought to use M90
for a same purpose.I have servo drive of Y.E.T it combination of Yaskawa with Israeli company, marketing by Omron in Israel and Europe.
I been talked with Unitronics guy he recommended to use Vision 120 ,he claim the Vision have better option for RS232 communication,he said it possible with M90 but very complicated .
The Vision is too expensive for me for that purpose so I went to AD DL05 with small display.
Since my application is in creation I don’t have more info now,I know it suppose to work.
I made in the past some application with Yaskawa servo and Exor(http://www.exor-rd.com/ )panels and I know they have drivers for Yaskawa product I made it with MP940 I don’t know if it will fit your application.
Please keep me posted about that I am very interested in connecting M90 to Yaskawa.
It will save me some money.
if you facing problems with Unitronics support I will try to help from here.

All the best

Got Results!

Hi all!

After an email to Avner at Unitronics to help me sort out some comms issues, and some encouragement, I am please to say, I got this arrangement talking.

Attached is my program. It's raw test stuff, no warranty express or implied, may not be suitable for anything - but it works on my test rig! There is Servo On (enable), Servo Off (disable) and Bi-Directional jogging at low speeds.

The important points are :

1. Use the programming cable for both devices, with a null-modem adapter.

2. The RS-232 parameters I'm using work with my drive as-is. In my Yaskawa Sigma II, it's the default arrangement.

3. The parsing was due to the damnable echo-back from the Yaskawa that keeps filling my receive buffer with a copy of the executed command ("I know what I told you to do, just tell me you DID it!") I'm trying to cut it down to "OK" or an error code.

Anyway, there is enough here for me to make a running start on programming all the commands I want. Using variables will allow me to enter setpoints for speed parameters, and execute indexes and homing, which is all I wanted The jogging is just a nice bonus.

As for the RS-232 mystery, I was mistook about the Unitronics - it can do seven data bits. Near as I can tell, the extra start bit for the Yaskawa is simply ignored, and sent as a "0" for outgoing messages.

To all, thanks for the help, and to Arik - good luck!

TM

Of course, it helps to attach the file...

Typo

In net 20, the second "A=B" block, MI 14 should be MI 104. Make that change and the rrors parse correctly.

Damned num-lock key...

TM