slc 5/03 to ethernet

I have 14 packaging machines w/slc 5/03's. I need to network them with a pc for data collection. All the plc program are the same. The dh+ port is being used by a panelview. I have done some research on serial to ethernet converters, but the prices varied quite a bit. The slow data transfer is not a problem. What's the best solution for this application?

Because you are connecting these only to a PC, and not to each other or to a supervisory PLC, you don't need the 1761-NET-ENI, which is probably the most expensive of all the RS-232/Ethernet converters because it embeds A-B protocols.

Instead, you will probably need a more general-purpose RS-232 to Ethernet interface.

I like the Lantronix UDS and Cobox models. The Moxa and Digi units certainly work, too.

You're going to be looking for something with a "COM Port Redirector" software utility. That will allow you to use RSLinx or other DF1 driver communication packages to talk to the "virtualized" COM ports that the Ethernet/RS232 converters represent.

I have been impressed by Kepware's OPC driver for the SLC-500 family. It allows you to directly access the Ethernet/RS232 converters over TCP/IP, instead of using a COM Port Redirector as RSLinx would require. I think that Kepware works most closely with Lantronix.

I've heard of the Anybus modules but don't have any experience with them.
Check out www.anybus.com/eng/products/abcoverview.asp

Why don't you network the whole lot together on DH+ , you have hardly any work to do , only change a few node addresses and you are away .
Buy yourself a DH+ card for the PC (sory , forget the model no) , use linx pro and bingo !

Fred Floggle said:

Why don't you network the whole lot together on DH+

Click to expand...

Well for starters, he said he has 5/03's...

B&B electronics has some good stuff. See if this will work for you.
http://www.bb-elec.com/product_family.asp?FamilyId=2


Regards,

Charlie

bill6142 said:

I have 14 packaging machines w/slc 5/03's. I need to network them with a pc for data collection. All the plc program are the same. The dh+ port is being used by a panelview. I have done some research on serial to ethernet converters, but the prices varied quite a bit. The slow data transfer is not a problem. What's the best solution for this application?

Click to expand...

This is nothing unusual but I am confused. Fred mentioned using DH+ to network them and 93 said they were 5/03....OK. The poster said the dh+ port is being used by a panelview.
WHAT DH+ PORT

If I am not mistaken the 5/03s Chan 0 is RS232 and Chan 1 is dh485.

Since they ALL have a DH485 port then why couldnt they be networked together using that. Even if each plc had a panelview on DH485 that would be a total of 28 devices...wont DH485 support 32?

Then just connect a PC to the network.

Re: Re: slc 5/03 to ethernet

rsdoran said:

Even if each plc had a panelview on DH485 that would be a total of 28 devices...wont DH485 support 32?

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Sounds logical doesn't it?

Due to my own bad experiences with DH-485, I personally don't trust it for much more than 10 nodes.

Of course it probably depends on the amount of data that is on the network. If you simply had 32 SLC's on a DH485 network, and there was no messaging between them, or no HMI's talking to them, it might be OK.

DH-485 may be able to address 32 nodes, BUT it should not be used with more than about 4. Even the AB literature states as much.

DH-485 was only ever intended to allow an a couple of SLC's a PanelView and a programming terminal to share the same link....anything more will suffer from inadequate performance...in all but the most lightly loaded cases. Because the system uses a "rotating token" system to allow each node to take turns at being the messaging master, the overhead on DH-485 (and DH+ its older brother) increases with the number of nodes connected. I forget whether it is a linear or power relationship, but at some point the amount of overhead becomes a large portion of the total network bandwidth that nothing much in the way of useful data is moved.

For DH+ that was about 16 nodes, for DH-485 (at 19.2k) it is about 4 nodes.

Dont do it

Bill,

Having done this about 10 years ago, I can tell you from experience, do not connect 14 production machines together through DH485 (which is what you meant to say if your using SLC5/03's. First problem, the 485 network is token passing, so each device gets its turn based on the adress you assign it. This includes all the panelviews and the PC. The first serious problem you'll have is panelviews not passing a operator button on state becuase the scan is so slow. So the operator will press teh panelview function key to do someting and although the key changes color for a second. The panelview wont have had it's turn to talk on the netwwork and the push wont get back to the appropriate PLC. Theres a dozen reasons why you never create dh485 loops like this. Best thing to do is split the machines up into 4-5 groups. Put 4-5 KTX-D cards into your PLC and let linx poll each group independently, this will shorten the scan rate down below 7 seconds or so. I have seen so many plants make this mistake and limp along for years trying to figure out why they have problems. I'm at a plant now that has to unplug the scada from a line so critical data being passed in a com instruction to another PLC gets there in time to cause the net index. A delay causes the cycle to miss at the downstream machine and it gets 2 "loads". Don't make this mistake!

Eric

I meant DH-485. Wouldn't I be better off using the serial port and converting it to ethernet. Then networking all the plc?

PhilipW said:

DH-485 may be able to address 32 nodes, BUT it should not be used with more than about 4. Even the AB literature states as much.

DH-485 was only ever intended to allow an a couple of SLC's a PanelView and a programming terminal to share the same link....anything more will suffer from inadequate performance...in all but the most lightly loaded cases. Because the system uses a "rotating token" system to allow each node to take turns at being the messaging master, the overhead on DH-485 (and DH+ its older brother) increases with the number of nodes connected. I forget whether it is a linear or power relationship, but at some point the amount of overhead becomes a large portion of the total network bandwidth that nothing much in the way of useful data is moved.

For DH+ that was about 16 nodes, for DH-485 (at 19.2k) it is about 4 nodes.

Click to expand...

Phil, sorry for dragging up an old thread, but can you point me to where this is stated? We have had loads of problems with our DH485 network with 5 SLC and 2 Micrologix on it. Thanks