Adriel

You can find a large list of PLC vendors that have OPC servers here: http://is.gd/4CJ5F Wassim Daoud MatrikonOPC

What type of PLCs do you have?

One potential avenue would be to use a Modbus OPC Server combined with an OPC plugin for Excel. You could also program Modbus directly into Excel, but that might be a bit harder. Adriel Michaud MatrikonOPC

Matrikon's OPC Server for Allen Bradley PLCs is fully functional for 30 days, after which you've got the 2 hour timeouts. Adriel Michaud MatrikonOPC

What OPC Client and OPC Server are you using? Are they on the same machine, or different ones?

What kind of performance are you requesting from it? (tags/second) I haven't used the TOPServer before to connect to ControlLogix PLC's, but some OPC Servers exhibit that kind of behavior (memory ramping, CPU usage moving up) under high stress situations. You might want to run Microsoft Perfmon and monitor the process CPU usage and memory usage overnight to see if the problem really happens all the time, or if it gets much worse at specific times. Adriel Michaud MatrikonOPC

I worked on something similar with Modbus over Airlink Raven modems. Using those modems and a frame relay, everything just looked like a big TCP/IP network except with a bit more latency. I used a SCADA-level OPC Server. No reason you couldn't do the same thing with DNP if you had an HMI that could handle it, or by using an OPC Server for SCADA DNP3. Adriel Michaud MatrikonOPC

Have you tried an OPC Client other than RSView, just to test it out? A successful connection with another OPC Client, running as the same user, would rule out DCOM configuration. DCOM configuration is usually the culprit in most cases when people have problems with a remote connection like this. MatrikonOPC has a test OPC client called OPC Explorer, and it's available as a free download. Adriel Michaud MatrikonOPC

Is the excel spreadsheet open at all times, or are you writing to an Excel file instead? There are some applicable OPC Tutorials at MatrikonOPC. For the VB route, if you sent me an email I could reply with some VB OPC Client examples. my email is adriel DOT michaud AT matrikonopc.com Adriel Michaud MatrikonOPC

Is your main goal taking data from an OPC Server and putting it into a live Excel sheet? If the OPC Server supports DDE (some do), you could connect directly from Excel. If not, you'll need an OPC Client for Excel. MatrikonOPC has one called OPC2XL that acts as an OPC Client / Excel plugin. Adriel Michaud MatrikonOPC

Hi Marjan, What type of connection settings are you using? sync vs async, DA 1.0 vs DA 2.05 vs DA 3.0, update rate, etc. Maybe the default update rate on your client is really slow. If you need a client to test with, Matrikon OPC Explorer can be used to test OPC connections. Adriel Michaud MatrikonOPC

MatrikonOPC does have support for their products. Here's our OPC Support Portal: http://matrikonopc.com/support/contact-form.aspx Adriel Michaud MatrikonOPC

Ahhh, test environment is using Ethernet to the S7 (a CP343 or something like it), and the live environment will be using MPI. Now I understand. Just off the top of my head, the tagname/syntax may change, but you'd be best off asking your OPC Server vendor about that. The MatrikonOPC Server can talk to both the Ethernet card (CP343) as well as MPI (over the Hilscher Netlink-MPI), but I'd have to talk to someone more technical than myself to see if the tagname/syntax would be the same.

Do you need an OPC Server with real data coming from the Simatic NET software, or do you need a disconnected OPC Server that simulates the Simatic NET OPC Server? I'll throw a few different problem/solution matches, because I don't have a grasp on your exact issue: First, to get a full loadout of your OPC tags from your existing OPC Server, you can use MatrikonOPC's Explorer. It's a free tool that you can use to connect to, browse, add, and export all the tags from your existing OPC Server. 1. Need simulated data from a test OPC Server so you can build your screens/logic. -MatrikonOPC Simulation Server can be configured to have a tag loadout that is similar to your existing OPC Server http://matrikonopc.com/products/opc-driver...ion-server.aspx -MatrikonOPC Chameleon can be configured to look EXACTLY like any OPC Server that you have, and will simulate data. http://matrikonopc.com/products/opc-deskto...-chameleon.aspx 2. Need real-time OPC access to S7-300 via MPI. -MatrikonOPC's Server for Siemens S7-300 can import data block symbols from Siemens Step 7 projects into the server. You can access the S7-300 via MPI through a Hilscher Netlink-MPI adapter. http://matrikonopc.com/opc-drivers/1330/index.aspx Adriel Michaud MatrikonOPC

My unbiased response is to use MatrikonOPC for everything Ken's nailed it on the head; we'd need an idea on what hardware you had and what you wanted to do. If you were looking at connecting to popular/standard PLC's, there are off the shelf OPC Servers that cover data access. If you're looking at a non-standard device and you were pretty handy with protocols, you could use something like Matrikon's OPC Genie to get the job done: http://matrikonopc.com/opc-drivers/815/index.aspx Typically when interfacing OPC Servers with PLC's, you use OPC DA 1.0a, 2.05, or 3.0. Most popular OPC Servers and Clients support all 3 versions of the specification, but be sure to verify with your vendor as the versions are incompatible with each other and some vendors do not support all of them. If you wanted to get your feet wet on OPC, we've got some tutorials available at: http://matrikonopc.com/resources/opc-tutorials.aspx Adriel Michaud MatrikonOPC