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We are experiencing message time outs on the data high way. A suggestion was made to speed up the DH+ from 57K to 230K baud. What would be some of the drawbacks of doing this, and what causes message time out faults? How can I resolve this issue? It is a PLC5 that we are dealing with.

Hello,

> We are experiencing message time outs on the data high way. A
> suggestion was made to speed up the DH+ from 57K to 230K baud. What
> would be some of the drawbacks of doing this, and what causes message
> time out faults? <

Message timeouts would most likely be due to communication problems on the DH+ network. Potential causes of these problems could include:
* Bad DH+ cable
* Bad connectors
* EMI or RF interference on DH+ cable
* A malfunctioning DH+ device
* Improper or missing Terminating resistors
* the list goes on.

Increasing the communication speed to 230K will not solve the problem. In fact the problem will more than likely become worse. Furthermore, do all of your DH+ devices even support the higher speed?

> How can I resolve this issue? It is a PLC5 that we are
> dealing with. <

Start looking at the DH+ Diagnostics data on the PLC-5 controllers. If you do not have DH+ diagnostics enabled for the DH+ channels then you
need to enable it.

Physically inspect the DH+ network. Is all of the "blue hose" cable from the same vendor? Are all of the connectors good? Are the correct terminating resistors being used? Etc...

Bradley G. Hite
Intertech Inc
mailto:bhite@myplc.com
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