I am using a SLC500 processor with a 1747-SDN Devicenet Scanner. I have over 30 nodes on the Devicenet network. Each of the nodes consists of the the same hardware device, a westlock controls d-pack. The d-packs are operating ballast control valves on a C1D1 rated barge. There is no room for errors on this vessel.
Anyway.... here lies my dilema. Everything works, but when a node drops offline (say for maintenance) the HMI still shows the last known state. The operator never sees a change on that device even though its inoperable. I need to find out how to map individual comm status bits for each of the devicenet nodes. This way the operator can pinpoint exactly which node drops offline. I know the info is available in the scanner for the simple fact that it displays it on the eight segment leds on the scanner itself.
Currently, the system flags a common alarm for when any node drops, then the operator has to open the PLC Cabinet, find the scanner error code, look it up, find which valve is associated with that node address, then find the drawing to find which valve has the address, then go trouble shoot that valve. These operators are not that fluent with this type of troubleshooting, and I must agree that it is cumbersome.
Please help... thanks...
Full Version: Devicenet Comm Status Bit
You will need to address the M1 files. Look at page A-3 of this manual
http://literature.rockwellautomation.com/i...um655_-en-p.pdf
http://literature.rockwellautomation.com/i...um655_-en-p.pdf
Umm.. yeah that page confuses me. Sorry, I'm slow!! 
Ok, lets say I have a have a valve module at node address 1. I map its input data byte to M1:2.0 bits 0-7 and its output data byte to M0:2.0 bits 0-7. How do I map a bit that will only trip when this individual module drops offline?
Ok, lets say I have a have a valve module at node address 1. I map its input data byte to M1:2.0 bits 0-7 and its output data byte to M0:2.0 bits 0-7. How do I map a bit that will only trip when this individual module drops offline?
I prefer the Installation Instructions (publication 1747-IN058C) for the 1747-SDN as a more succinct summary of the data tables and features of the modules.
What I do is perform a Copy instruction to pull the 1747-SDN status information into an integer table periodically (like every 100 or 200 ms). Each reference to the M0/M1 files takes a couple of milliseconds of CPU time so I never address individual bits directly.
Say you're copying the Device Failure Table (M1:216-219) into an integer table N100:0-3. If a device was Node 12, the bit N100:0/12 would be set to 1 when that device's DeviceNet connection was broken.
I'm going to have to re-visit the topic of whether a device shows up in the Device Failure table if the 1747-SDN is rebooted and no connection is ever made. That may have changed in recent versions of the 1747-SDN firmware.
What I do is perform a Copy instruction to pull the 1747-SDN status information into an integer table periodically (like every 100 or 200 ms). Each reference to the M0/M1 files takes a couple of milliseconds of CPU time so I never address individual bits directly.
Say you're copying the Device Failure Table (M1:216-219) into an integer table N100:0-3. If a device was Node 12, the bit N100:0/12 would be set to 1 when that device's DeviceNet connection was broken.
I'm going to have to re-visit the topic of whether a device shows up in the Device Failure table if the 1747-SDN is rebooted and no connection is ever made. That may have changed in recent versions of the 1747-SDN firmware.
Wahoo.... that works like a charm... thanks a bunch. Ok my only other question on this topic is what exactly is the "Device Idle Table" used to indicate, and what is the "Device Active" table used to indicate?
I played with it a little bit, but I dont see any change in the data in those ranges when I take the device offline or put it back online.
I played with it a little bit, but I dont see any change in the data in those ranges when I take the device offline or put it back online.
QUOTE(rlbarras @ Nov 23 2006, 01:01 AM) [snapback]44223[/snapback]
Wahoo.... that works like a charm... thanks a bunch. Ok my only other question on this topic is what exactly is the "Device Idle Table" used to indicate, and what is the "Device Active" table used to indicate?
I played with it a little bit, but I dont see any change in the data in those ranges when I take the device offline or put it back online.
Device Idle Table represents that the device is connected not perfoming any operation that is when the processor in program mode & Run command in dnet not activated(represents the Idle LED in front of the module
Device Active Table represents that the device is connected is communicating
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