RS485 For Hypertherms

If you are talking MoBus RTU there is no CR/Lf. It is pure hex.
( With some high level languages you have to watch carefully that they really send out the hex. In windows I had once the problem that the lower hex ones had been automatically transformed to control sequences. Grrrrr)

Only in the very old ModBus-ASCI have been with CR/LF. But that is not used often anymore...
M5C
Mike

Mike_Eitel wrote:

Only in the very old ModBus-ASCI have been with CR/LF. But that is not used often anymore...
M5C
Mike

But in this case its Modbuus ASCII

Old fishermen never die, they just smell that way
;-(

phillc54 wrote:

In the Hypertherm docs they mention a CR/LF at the end of transmission from master to slave but when they mention the reply there is no CR/LF. Is this correct?

Edit: Hey Rod I see one of Toms links is from your neck of the woods.

Phill, I think the answer is on page 4. They assume your software strips out the CRLF terminator

CR/LF Carriage return, line feed in hexadecimal: 0D0A. The end characters are typcially removed on incoming messages by the CNC.

And yes, I lived in Toowoomba where USQ is for a few years.

phillc54 wrote:

Well, I have read that doc a gazillion times (or I thought I had) and didn't see that bit. I think this is frustrating me, I'll take a short break...

That was my experience learning Modbus RTU/ASCII as well,

What makes things more fun is the way the register values start, It can either start with a 0 or 1 depending on vendor it could be one of either! I have a servo drive that I programed a PLC to control and setting up the Modbus code first time was a real head fuck.

The best is to get one of the free serial analyzers and sniff both sides of your communication with a second pc... One look on the screen and you win lot of time..

phillc54 wrote:

Yeah, I have an 8 channel logic analyser but the problem I was having with a VMware guest was that it wouldn't open the port consistently.

You trying to get the Hyperterm to talk rs-485 for THC?