Baud Rate??

I need to know if a PLC and HMI can communicate at all having different Baud rates, 2400-9600?
thanks in advance

The short answer is no.

Baud rate must be the same on both devices.

If you mean that HMI has one baud rate and PLC has a different one, the answer is no.

I have an HMI that is slow in writting an input to the PLC.

Looking at the PLC online, when I press a button on the touch sreen it takes about a second for that bit to register on the PLC which in turn delays the output on the rung. HMI DP321 PLC DL405 both from Automation Direct. Does anyone have any suggestons.

Favian said:

I have an HMI that is slow in writting an input to the PLC.

Looking at the PLC online, when I press a button on the touch sreen it takes about a second for that bit to register on the PLC which in turn delays the output on the rung. HMIP321 PLCL405 both from Automation Direct. Does anyone have any suggestons.

Click to expand...

Have you checked your HMI application the "button" setup? You could set the "holding time" for the button to a lower time let's say 50mSEC instead of a 500mSEC or so. What's your current :holding time" for the button itself? If it's set to something outrageously high a second delay sounds pretty quick.
By the way, "Holding time" is the time you need to press the button prior to initiating any action, Allen Bradley and Siemens HMI's is what I have used but I'm sure Automation Direct has a similar setup for their buttons

In addition to holding time, see what the poll time is on the HMI (look in the database, or the driver, sorry not familiar with that particular HMI). That 1 second sounds like a standard polling speed.

I do not see what this has to do with the devices having different baud rates. I gaurantee the baud rate will not effect how quickly your output turns on in any way that you'll be capable of noticing.


-jeff

Devices can be capable of different baud rates AND may communicate when the settings are different i.e. a modem may be 1200 baud but the PC was capable and set for 9600, it could work but WOULD work at the 1200 rate; which if memory serves me would be around 3ms.

I suspect as others do, the HMI has a polling setting.