Large project, need assistance with ideas

[rQx]

Thanks alot for the links! I will take my computer with me home one day and experiment some with the communication loop I'll make

 

[GaryS]

Hi I am back again to try and address some of your concerns.

Client wants to make a change to the ladder code at some later date.
That would never ever be a concern for me. Once I develop the code and it’s installed and running Client accepts it and signs off its there’s. If they want to make a change after that it’s all time and materials. Money in the bank for me. If it takes 2 to 3 days to download the change to all the units that’s the cost of the change easiest money you will ever make. Here again keep in mind if a change is made it must be down loaded to all the units otherwise you could lose track of the changes and end up with a whole new set of problems.

As for splitting up the network and using both hardwire and wireless connections. That would just complicate the network way too much. Trying to manage that would be very difficult, you would have to always remember what was connected through what. And each unit will still need a different IP address Consider what will happen if one unit was removed for whatever reason. What if the unit removed is a master you would then lose all the slaves connected to it. Somebody would have to go out and reconnect the units. And maybe another master is not available then what do you do. Not something I would want to do.
Leave it all wireless you will need the routers anyway so use then. In addition all the units will not be the same some will have a wireless Ethernet and other will have hardwired Ethernet. Mix and match connections could be a problem down the road. Again keep the network as simple as possible.
If were to do something like this I would use 4 subnets and use 10-190 as the last octet on the IP address. This will keep the bottom and top addresses open to add a new unit. Where I to build the panels I would set the default address to something like 5 for the original download then after you download the program go back in and set the IP address to the correct values.
Just as a side note I would paint numbers on the units or the panels with the last 4 digits of the IP address it makes it a lot easier to find the unit both in the yard and in the network when you have a problem at a later time.

When you do place the order ask your distributor to deliver the materials over time as you need them. That way you don’t have to be concerned about managing your inventory let them do that for you. I don’t know about your area but the distributors I work with do that all the time. You get delivery when you need materials and you still get the discounted pricing. In addition on a project of this size I would recommend that you always keep spare parts on your shelf. Then at the end of the job sell then to the client so they have spares if needed. With that many units you can bet you will get a bad one or two. With a spare on hand it wouldn’t hold up your project.

Any standard SCADA or HMI should be able to upload set points and download alarms and date from each unit as needed. So I don’t see the need for a master PLC to do that, in fact I think it would put an additional load on the network that will gain you nothing in return.
This would be a good project for Net Studio I think once you try it I think it would be clear why it’s better.

I think this would be an interesting fun project to work on. If the project was on this side of the big pond I would welcome the opportunity to help you more directly. Good luck I hope it works out for you.

 

[GaryS]

I just thought of something else, it almost slipped my mind not that I have much of a mind left.
You should have a local display to allow for local set point changes display alarms and operational status
I would consider putting the display on the network as well. I know this will double the number of IP addresses. But it would allow you to update the display over the network if necessary.

 

[ndzied1]

I have been following this thread and have thought of another way to look at this that might be interesting to you.

Perhaps it would be easier to select a small PLC with everything on connectors and then when a change comes through, program a batch offline, swap them out (easy if everything is on connectors) and then program the next batch. The trick there is to make sure you are documenting what version is in what PLC. A trick for this is to use a spare output (hopefully you have one) and blink the light in a certain way for a certain program version.

Another thought would be to pick a PLC with a memory card. That way cards would be swapped to change the program.

Lastly, there are some PLCs with a programming tool that lets you plug into the PLC and upload a program to it.

Could be simple enough to just have a tech do most of the running around.

 

[rQx]

You are right ofcoarse it would make me easy money, I just want to make sure it's the best way of doing it so I don't end up doing it the hard way and end up costing my customer more then it should

Maybe master/slave set up isn't to good after all. I think I worry to mush on the cost for the customer instead of making it as fail safe as possible.

I will have to read up on the wireless equiptment and how to connect a siemens LOGO to wireless network. It sure would be the easisest and no installation needed for the network exept for the wireless.

The reason I want to do this with a LOGO is that it has a display where I can change the variables and IP adress.

Yes it's possible over here to to get the deliverys over a long time so I don't worry about that.

But WinCC Flexible 2008 Runtime can only communicate with one PLC, that's the reason I want a master PLC. But again I only have basic knowledge so maybe I can connect 700, I will discuss this with Siemens in Sweden before starting to build aswell so I start with the best solution to start with. Also the reason I wan't to use Siemens is that I get a whole package with just Siemens and if I get some trouble it's all Siemens and I have really good support on Siemens here. However, I will look up Net studio since you've sold it so good

I appreciate your help very mush and I think that this will be a good learning ground for me.

 

[GaryS]

it looks like you are getting a handle it good luck
here's a link to the Net Studio drivers for PLC's
www.ingeardrivers.com
I have been using them for many years they work great
for this project I would look the ActiveX control it gives you better control over the communication