Scada system

[Scada_Bart]

Hello, I'v got a few troubles in designing a SCADA system in our factory. I'v got to design a scada system for a production line. This line has different types of machines with all a PLC in. Following PLC's are present: S7-314, S5-135, S5-95U, Omron CQM1-CPU21, S5-100U and one S7-200. All these 'machine' PLC's should communicate with each other to one PLC which collect all the data and sends this data to a PC which is connected to a SQL database. the problem is that most slots are full, only the S5-135U has a couple of empty slots. I thought to put an extra PLC, for example S7, next to the existing machine PLC's so I can collect information from the existing ones and transfer them to the central PLC. this way I can use profibus which is most practical considering the length of the line. I want to collect following information:when is the machine running, how many produced, error messages... These signals are all availbale in the PLC's. But is is possible the put extra racks in while the existing ones are full? And is it possible to communicate between the different types of PLC? Is this the best way to collect info or are there other way's to do this? Because a PLC is not cheap. greetz

[RheinhardtP]

Hi Looking at your post i assume that the Scada is a new addition to your plant. When the initial plant design did not allow for connectivity between the different control systems there is always going to be money spent interfacing the various systems. This is something that you wont be able to bypass. You can look at getting different communication cards for the various types of PLC's. Usually there should be a netwotk topothology which specifies Primary system (Overall PLC network say Ethernet) and then your lower order communication for plant (Profibus,Modbus ect.) It would be a good idea to have Ethernet as your PRIMARY network system, for ease of compatibility with other exsting hardware. Know that interfacing all your above mentioned systems will take alot of re-configuration, hardware installation providing you dont already have ethernet functionality. Standerizing on PLC equipment also makes it alot easier for configuration. It also helps maintenace personnel when there is a standard Kind Regards RheinhardtP

[KinK]

I agree with Reinhard. It depends also on the amount of data and what you want to do with it. if you just want to log the error codes and such then you could just set up a wireless RS232 system which most PLC's will be able to use(19.2k possibly) then you should be able to find a scada system that has the ability to talk to all of the diff types of plc's you have then you can just poll them and pull the data down every few seconds. To get any more detailed you will have to supply some more info ie what you want the scada system to do. do you want it to have the ability to control the line ... there are lots of ways to do it. give us some more detailed info... Peace

[Crossbow]

I wouldn't try to network all the PLCs to each other. I would try to network as many of one brand to each other as possible, and then bring them to a PC with an OPC server. Instead of making a PLC the data collection device, use a computer. Almost every SCADA package out there supports communication via an OPC server, and almost every PLC vendor offers an OPC server for their products. Or there's always Kepware, who makes one OPC server that will talk to almost any PLC.

[Guest Guest]

To overcome the expansion problems with the PLC's, we installed Proface touchscreens to each Mitsubishi PLC, each screen had ethernet capabilty and we used the LS area of the code to carry out the data collection required. This not only freed up space on the PLC but provided us with a very useful user tool on each machine as the Touchscreen is being used for total machine control. Each screen is connected via a series of hubs and a master server, which in turn is connected to the master PC - we have an additional 3 slave PC's on the shop floor for monitoring purposes.

[Friday]

Hi, SCADA is a good choice to control/monitor all PLCs over network. You can collect all PLCs data into SQL Server via OPC Server. If you design to use OPC Server, you need some SCADA software or OPC ActiveX control to connect to OPC Server and collect data into SQL Server. I ever use VB.NET in my project to get data from OPC Server and send to SQL Server. I use OPC ActiveX control on VB.Net appliction. You can use VB,VBA,VB.NET,C#,VC++ with OPC ActiveX control. The SCADA software is easy choice but expensive. I choose VB.NET because it 's easy and flexible for our requirements.

[GerryM]

Which ActiveX control do you like to use?

[Nathan]

I agree with Crossbow. Use OPC servers to talk directly to your existing PLCs. You had mentioned that you wanted to log data to SQL databases. Check out FactorySQL for that datalogging. It's cheap, easy to use, and reliable. You can log to most types of SQL database (MS SQL Server, MySQL, Postgres, Oracle, etc). The best way to get info is by signing up for a 40 minute web demo here. ---- Nathan Boeger Integrator, Microsoft Certified Systems Engineer Inductive Automation