Helllp dh+ failure!

sparkytex

Lifetime Supporting Member
Join Date
Jun 2013
Location
Port Hardy B.C.
Posts
354
My DH+ crashed all of the sudden. an EQ7000 DH+ to Ethernet converter was unplugged by accident and then plugged back in and since then all of the PLC's have lost their DH+ communication, our operators have zero control, which is not good. In RSLinx the PLC's keep going in and out of communication saying remote run/comm error. I do know why it the DH+ wont come back online. Any tips and help would be much appreciated. Theirs all kinds of PLC 5 and SLC processor's on this network. Is there a way to reset the network? Is there an end of the line resistor gone or something?
 
Can you go on line to one of the 5's and check the node table status. A 1 indicates "station present" Also, try physically disconnecting units (if you can without effecting the process) in order to isolate one that may be bringing the network down.
 
I cant get online with anything because all of the processor's are always going in and out of communication. I'm a bit weary about disconnecting processors as the place is still running and don't want to take anything down
 
Can't go on-line via serial port?

Regardless, if things are going on and off line then you've got to find either the disconnected/shorted wire or the back controller. I see no way of resolving the issue without stopping things.
 
yes I'm sure I could could go online via serial port, right now I'm going to unplug the processors that aren't even showing up on rslinx, then I'm going to start unplugging the processors that have Ethernet as well as DH+ so it wont matter if its unplugged. Where is the Node table status?
 
It's likely that there is a broken or corroded conductor in or near the 3-pin connector that was unplugged.

Whenever I work on a DH+ connector that is years old, I like to get out the cable and wire strippers and make a nice new shiny stripped end and clean up the years of corrosion, dirt, and fatigue that tend to collect on terminations like that.

One of the great things about DH+ is that it will run on improper and damaged wiring very well. That's also one of the bad things about DH+, because you often don't know that the wiring is degraded until it fails entirely.


Remind me to tell the staple sabotage story again sometime !
 
Thanks to everyone for their input and suggestions. At about 9:00 pm last night after hours of searching through cables and connectors I determined a cable was faulty that ran about 800' from a main trunk to 5 SLC 5/04 processors. There is 18 devices on this DH+ network so it was quite the battle trying to find the issue. Luckily another line ran out to the same building for another adjacent PLC that was still in tact. I was able to take off that trunk line over to the 5 SLC's that needed a connection. At about 10 Pm everything was back to normal and I had most of my hair left.

Thanks again to every one for their help, it's much appreciated!!

Cheers, have a great weekend!!(y)(y)
 
Good job Sparky. I've had some late nights because of DH+ so I know how difficult it can be to troubleshoot sometimes, especially since our mill has grown up over the last 25 years and we haven't kept good records about how the network really is. I've had a few arguments with the other guys about how the network looks on paper vs how it is really wired. I've even had to disconnect some wires just to prove my point. Ken's right, DH+ can be very forgiving, until it's just not. Then the trouble starts.
 
I couldn't agree more, it can be great until it really goes wrong then it's a headache! Our mill is the same way, no records on how it's actually wired in the field. Cheers, Tex
 

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