Didn't want to turn this into a documentary (Joking)
But here goes!!
Anwers to questions, followed by result.
Ken Roach
Do you mean that SLC-5/04 controllers are displaying blinking green DH+ LED's instead of solid green?
Yes, it seems that the network would slow, until 3 or up to 5 nodes (always SLC5/04s and no particular node) stop communicating across it, then the network would regain speed.
Do you mean that PanelView terminals are displaying communication-related error codes?
Yes, when the node/s it recieves/transmits data from "falls off" network.
RSLinx browses are showing red X's in the RSWho window
Yes, then of course any messaging/control from associated PLC will not occur.
While you're checking out the waveform of the DH+ signal, be sure to also physically measure the resistance between blue and clear wires (with all the nodes unplugged) and measure the resistance between the shield and ground, verifying the network shield is only grounded in one location. Check the signal using AC coupling as well to see if the network is riding on top of a 50 or 60 Hz induced signal.
"Belled out" cables.(Continuity Testing) Resistances of all cables all within manufactures specs (If in doubt,replaced it).
Too little wire can be a problem, too. I always make sure my DH+ cables are 10 feet minimum.
Totally agree, shorter cable runs are>10ft
Remember that if you're running at 230.4 kb/s you can only run 2,500 feet of cable.
Due to overall length of network being >2500 ft and <10,000 ft staying with 57.6kb/s
Jesper
Or are you splitting the DH+ into 2 networks?
Yes, have done so,
Now
Network A = 8 nodes (5X SLC5/04s 2 have always had PV550s serially connected, 1X PV550 DH+, 1X PV900 DH+, 1X Gateway)
Network B = 12 nodes (2X Servers, 5X SLC5/04s, 4X PV550s DH+, 1X Gateway)
Conclusion (I hope!!)
As stated above, have split the network into two with a Contrologix Gateway. This has been running for the last 48hrs and nil nodes have dropped off the network or erred. Network has not slowed
Traffic was never an issue as I believe we had our control, messaging, etc between the nodes correct.
Before/ Traffic = 34% - 40% After/ Traffic = 22% - 26%
Bad Packets being sent - Nil
A major concern was the Token Passing.
Before = 100% After <80%
The main culprits were the PV1400e and its associated SLC5/04 as this was almost constantly at 99-100%, this has dropped dramatically since replacing it with a PV550. (Yes, I tried extending its polling time and limiting messaging and other modifications to no avail)
Bandwidth, as thought, vastly improved.
The max. number of nodes on a DH+ Network was a vital clue and took some searching to find.
I'll stay with my decision of splitting the network.
QED