Hey guys. I am working with a Point I/O 1734-232ASC ASCII device.

I have attached a screen shot with me online with RS Networx, DeviceNet.

I have an issue, that if the rs-232 device I am talking with goes down, like someone turns the power off to the device (printer), that I loose communications.

Normally if the communications is ok, I see the transaction Id increment, and I use this as a "heartbeat". However, when the communications drops, there is still data in the device. Parameter 14 stores the string data or reply from the printer. As you can see the data, it is byte swapped, switch every other letter.

Is there anyway to purge this buffer in the device? I can't clear it in the M files or N files, because the source is from this device, so when I clear the M files, this device rewrites what is in the buffer anyway. I'd like to clear the buffer in the device if that is possible.

You may want to try to get a message to Ken Roach. I know at one time he was working on the same thing on another forum but I can't seem to find the link

Dear Chako:
It has been a year or more since I last used the 1734 point Io in an application, but I seem to recall the only way to clear the receive buffer is to initialize the device. You can do this with Logix 5000 and right click on the device in the I/O tree and investigate properties. If doing it from Logix 5000 gives the desired result, then check the command structure to the device and you should be able to find Reset command you need to send from ladder. Good Luck.

BobLfoot

P.S. - We found it was easier to watch the receive buffer for data change and then move it to a workign register and always reference the working register in our code.

I have never used the 1734-232ASC module before, but if Bob is talking about the reset in the image below, most modules, though I can't say for sure about this one, can be reset using a message command.

Disclaimer - This command is not meant to be used to reset drives, fuses, servos, or any thing else you normally see a reset for. From what I have gathered from using it, it is the same as cycling power but could be wrong. I had a module once that was a little touchy (major power problems) and it seemed to do the trick for getting it back online

For newer RsLogix 5000 versions (don't know when, never noticed it until I was looking for values for old method)
Message Type - CIP Generic
Service Type - Device Reset
Path - What module you want to reset

For older RsLogix 5000 versions
Message Type - CIP Generic
Service Type - Custom
Service - 5
Class - 1
Instance - 1
Attribute - 0
Source Element - Any SINT, no value needed
Source Length - 1
Path - What module you want to reset

TW - The Reset Button in your image is exactly what I referred to, just didn't have any sample code handy.