Ethernet Device Servers and Small HMI System Design

The theory of operation is quite simple. Since most serial protocols only allow a single master, HMI-A is set up as the "I/O Server". It moves data between the HMI application "object database" and the slave devices by the serial protocols. The second HMI-B must indirectly access this data by network. If HMI-A goes down, HMI-B must be reconfigured to act as "I/O Server" and the serial cables moved from HMI-A to HMI-B. For the EWS to access the slaves, the serial cable is likely moved from HMI-A to the EWS, which puts the device "off-line" and allows the device vendor's special configuration tools to be run.

View Entire Paper | Previous Page | White Papers Search

If you found this page useful, bookmark and share it on:

 
Embedded Star Newsletter
Don't have time to visit Embedded Star everyday? Then sign up for our free newsletter. We'll send you an email when we have something to share with you. Your email address will be kept confidential and we will not share, sell, or rent it to anyone. You can unsubscribe at any time by clicking a link in the email.

Enter your email address to sign up for our free newsletter:   

If you are familiar with RSS feeds, you can also sign up for our free blog feed. Our RSS feed is updated in real-time while our newsletter is updated daily.