DeviceNet question

silver creek

Member
Join Date
Jun 2018
Location
il
Posts
6
Good Morning
I have a question in regards to DevicNet
We have a older system PLC 5/20 with a 1771 SDN B installed it communicated with a couple of Joucomatic valve banks 1 no longer works and I cannot get it repaired (tried twice).I have a new Numatics 503 series as a replacment that I need to add to the network. I have the EDS file installed in RSNETWORX for DevicNet there are only 2 items on the network both Joucomatic valve banks.
The question
Can I just log on and replace the bad valve bank with the new one and the world will be fine or is it a lot more complicated.
The new valve bank is set up to match the old as far as location of single or double valves
Thank's
Jeff
 
Welcome to the PLCTalk forum community !

Can I just log on and replace the bad valve bank with the new one and the world will be fine or is it a lot more complicated.

It depends on how much data and how it's mapped.

If the data connections are identical (like both products get 2 bytes of output data and Bit 0 = Valve 1) then you can probably just swap the devices.

DeviceNet has a feature called "Electronic Keying" that tries to make wrong-device-actuation rare by requiring that a device be from the correct vendor, device type, and device product code before it will start taking commands from a scanner.

If you want to swap a Brand A device for a Brand B device, you will need to turn off Electronic Keying. It's a check-box in the 1771-SDN Scanlist configuration applet inside RSNetworx for DeviceNet.


If the devices have different I/O sizes or different meanings for each byte and bit in the I/O connection, then you will have to create a new data map entry and/or edit your PLC-5 program.

Can you point to some details about the Joucomatic and Numatics products, specifically their user manuals or Electronic Data Sheet files ?
 
Ken
Thank you for the reply the links below are what I have for information on the products. I was able to find a EDS file on the Joucomatic valve it is a Buslink generation C valve island ( about 18yrs old like everything else)
I was able to add the new valve bank to the network map in RSNetWorx (off line) and no longer receive error message about device not being registered on laptop. I put it in the same location node 2.
If I can add to map no need to turn off electronic keying?



http://www.asconumatics.eu/pdf2/3835061gb.pdf https://www.yumpu.com/en/document/view/1951348/generation-c-generation-c-asco-numatics/11
 
You definitely will need to turn off Electronic Keying, because these devices are from different vendors.

Doing the data mapping is going to require more details.

In RSNetworx for DeviceNet, open up the Scanlist editor and look at how many bytes of Input and Output data are configured for the valve manifold.

Then you'll have to look at the configuration of the new device, and figure out if the same amount of data with the same meaning is available.

Obviously "valve banks" have a lot of variations in how many devices are connected and how much data they use. A double-acting valve might be mapped differently from a single-acting one, etc. There are often Input and Output devices in the valve bank assembly.
 
Ken
Thanks’ again
All this information is from RSNetWorx DeviceNet (off line) I do not want to connect until I know I won’t
---- It up. (Which is a good possibility anyway?)
They look to be the same both 4 bytes each for both input and output poll rate every scan listed in the summery section.
I did notice that the older Joucomatic valve bank in the properties section under I/O Data there is only 4 Bytes listed as available both I/O and in the Numatics valve there is 6 Bytes listed for Input and 4 for Output. But 4 and 4 appear to be being used?
Since 4 and 4 are listed under summery section in the scanner would that be OK?


In the attachment is a picture of the summery
Jeff
 
Sure; they are both DeviceNet things and will work together. It's hard to find computers that will host a real PCMCIA card anymore, but if you've got one, go ahead.

If this were my system, I would carefully note which words are used to control the valves on the old manifold, then map the new manifold to a *different* section of memory with the 1771-SDN.

Then poke values into those memory locations to verify that each bit turns on the valve you expect.

Then re-map the data back to the original locations.

Because of the different I/O sizes this might require an "advanced mapping" where you don't map the whole I/O connection to the same block. You can have up to four different segments of data.
 
hhmmm...manual mapping on a 1771-SDN..

not got good experiences of that.

My predecessor decided to add a new rack and slip it into a memory area on the D-Net config that was not being used (trying to be efficient), which was fine until I needed to add card number 8 on a Flex Rack...no memory space to continue the mapping, so tried to split the memory map over 2 areas. Never got it to work....
Ended up adding a new rack for that one new card so that mapping was automatic.
To shuffle the old stuff to organise it properly would have been a headache with PLC addresses and SCADA references..

On the flip side, we have a PLC5/1771-SDN network that has SEW inverters that are obsolete, and we wanted to slip in the new inverter in place of the old one. EDS files gathered, try the config....it took a lot of discussion between us, Rockwell and SEW to decide the correct length of input and output words to use, but we got there, (I think).
We also had power issues with the 24V DC, which meant that every time we connected to the network, the nodes could not all be seen....that needed a Devicenet rated 24V DC power supply...

So, when tinkering with older devicenet, be afraid, be very afraid.........
 
Silver_Creek has a good question, involving integration of obsolete devices from multiple vendors, using straightforward features of the DeviceNet configuration software. It's entirely solvable, but it requires experienced advice due to the age and complexity of the devices. The answer could help him, and maybe a future user of similar devices who happens across the thread.

There's nothing about his question that suggests the presence of a bug, a defect, or insufficient vendor documentation.

Snarky comments can be amusing and help us defuse frustration, but I think that with new Forum members, they tend to erode confidence in the technology, in the experts posting on the topic, and in the Forum itself.

Electronic Keying, I/O connection sizes, and segmented memory mapping don't have to be intimidating or confusing. Let's try to keep this thread on track.

Football season is coming up soon. THEN we can start some trash-talk.
 
Thanks for the reply's
I do have a old laptop that will accept pcmi cards although now I need a floppy disk reader to install the driver for it. It has been a really frustrating experience my filler has been down for a month and we are about to lose contracts. I had the valve bank sent out to be repaired was told they could do it ( customers were OK with that). after returning it because they did not repair it the first time received back again and still did not work.( 3 weeks time) So I ordered a new one different manufacturing brand as the original is obsolete was told it should be easy, starting to think its not.
My problem is I am just smart enough to ---- it up.
I have ordered a floppy reader and a larger hammer just in case.
I guess I have something to think about this week when on vacation o_O
 

Similar Topics

I have Frontline NetDecoder Software and a 1784-U2DN in hopes of troubleshooting a DeviceNet issue. Randomly we have Nodes that stop communicating...
Replies
7
Views
2,423
When going "Online" with a running Devicenet network using RSNetworx through a 1770-KFD, will all physically connected nodes appear? I was under...
Replies
3
Views
1,602
Hello This is my first post on this forum, so bear with me. I'm working with a DeviceNet system where there needs to be a transition on the trunk...
Replies
5
Views
2,473
Hi all...i am replacing a couple of motors from 3 to 5 hp....I am also replacing the drives. Do i need to remove the old ones from the scan list...
Replies
5
Views
2,720
Evening All, Little bit of background - Last week I'm asked to attend a "plc fault" with one of the techs - usual story of very little info...
Replies
11
Views
4,047
Back
Top Bottom