Steve Nelson

We have a PLC that controls a diverts for cartons.  The PLC talks to a host to get the divert code and then this is used to trigger diverts through device net.   The issue we are having started back a few months.   We are getting good scans and the information is being sent to the host and back, but cartons are not diverting 100% of the time.   If we remote connect to the PLC and have the program open, the issue goes away.  When we disconnect, it issues occur again.   The PLC has a wired connection through a network switch.   Is this a problem with the PLC or with the network switch or somewhere higher up in the connection?  If it is the switch, why does the issue disappear when we are connected?    We are remote connecting with a laptop and the connection we use is wireless.

All communication from the PLC to the Host (database) is over Ethernet.  Communication from the PLC to diverts on the actual line is device net.

But when I go online, it improves.    I may have our network team look at the switch and how the port is configured on that switch.  Once I find out more from them, I will add more to the post.  Appreciate the help.

5/05 PLC.   Ok, so why does it improve when I am connected?    When I disconnect, the issue appears.

We receive back a 2 digit divert code that is passed along from zone to zone to trigger the divert. A message is received from the scanner into a string and it is modified and sent to the host.   We have gap control timing on the PE after the scanner, 525ms to allow for adequate spacing.