Setting up S7 CP 343 - 1 to transer to S5

[Thomas_v2]

Do you call the SYNCHRON FB in the S5?

I would check step by step all points which are mentioned in the Siemens FAQ.

 

[russg]

It's ok i've cleared the system fault light. Just checking now if any improvement.

 

[russg]

WE HAVE LIFT OFF!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Thank you Thomas for all your wonderful help. I can not thank you enough!!!!!

Danke sehr!!

 

[Thomas_v2]

Danke sehr!!

Bitte

What was the problem, the number of the TSAPs or the wrong FCs in the S7?

Anyhow, it works and it's OK.

 

[russg]

I think it was the number of the TSAPs. I changed the FC's at the same time so it may be them as well.

Thank you very much. Now I can get on with the rest of the job of assigning all the data.

 

[russg]

Btw, do you have a ******* wallet? I would like to tip you for your amazing help.

 

[russg]

After this great success today, I've realised I may need to use a Fetch or Write function too. Can someone please explain to me the difference between a Fetch and Write function and if I need to use both together?

The reason I think I need to use one of these functions is because I have many tags I need to read and write to in the S5 PLC. So I'm assuming I maybe use a Fetch Active on the S5 side with Read and Write?

 

[Thomas_v2]

The SEND/RECEIVE communication is a communication between two blocks on both sides.

A calls SEND to send a data-buffer to B.
B receives the data with RECEIVE, and writes it into the specified data-area. The data-area is specified by B.

A calls WRITE to send a data-buffer to B, it says write it to data-area XY.
B calls only a WRITE passive. The data-area is specified by A.

With FETCH/WRITE the partner who is calling the active blocks can read / write any data area from / to the partner. With SEND/RECEIVE both partners have full control which data can be accessed.

If you have to access many different data areas (DB, M, I, Q), you can use FETCH/WRITE, or you can use SEND/RECEIVE, and pack the data together into a single datablock.

 

[russg]

Thanks again Thomas.

So, say I have DB50 in the S5 that has Data that I want to read values from, putting them values into the S7, but the DB50 also has bits and words I want to write to from the S7. Am I best to create a Write Active from the S5 and a Write passive from the S7 for the whole of DB50, or am I best to Send the data from the S5 to the S7 that I want to Read, and Send the Data from the S7 to the S5 that I want to Write to? The only problem with the 2nd way is that it will take me a lot more time figuring out which bits need to be send and which need to be read?

 

[Thomas_v2]

With FETCH/WRITE the S7 can only act as server (passive). I think FETCH/WRITE can be best compared to PUT/GET in the S7 world.

I've made retrofit on many S5, but have never seen any FETCH/WRITE connection. I would chose SEND/RECEIVE when communicating with a S5. Making two datablocks for each direction (S5->S7, S7->S5) and exchange the complete blocks via send and receive. Then you have a clear interface between the two Plcs, and no one is poking around anywhere in your Plc memory ;-)

 

[russg]

I've had a play around this morning with the Fetch and Write, but can not get it working so I've decided just to stick with the Send and Receive like you mention. And like you say it's better to know which data is being moved to where.

Thanks again for all your help Thomas. You've helped me sleep better at night

 

[russg]

I've encountered another problem:

The Send/Receive blocks can only send so much data at once.... say 500 bytes. I need to send and receive about 10 Data blocks about 500 bytes long. At first I thought I could do this by just assigning more send and receive handling blocks, but i've realised that isn't going to work. So i think I need to send one block at a time and use that block as a buffer zone, then transer the blocks into other places at the receive end. I'm thinking of doing this by assigning a number to the last dataword of the block that is not being used. Say DW 502, with my buffer Data block as say DB 40.

So I will move 1 into DB40.DW502 then load all of DB1 into DB40. When the PLC on the receiving end gets the block, it will check to see what number DW502 is. If it is a 1 then it will move the contents of DB40 into DB1. I'll do the same for DB2, moving 2 into DW502, then doing the same on the other end if DW502 has the value 2.... and so on.

So is this a standard way of doing things when you have a lot of data to exchange between PLC's?

Also, I know how to move a whole Data Block from one to another in S7, but I do not know how to do this on a S5 115U PLC. Can anyone advise me please?

Thanks

 

[Thomas_v2]

Maybe in this case a FETCH/WRITE connection is easier to handle than data-multiplexing in software on both sides. Then you have to call the 10 WRITE and 10 FETCH calls (or what you need) successively.

Without multiplexing a SEND/RECEIVE connection, you could configure several SEND/RECEIVE connections, and use each "channel" for the maximum possible size. If the probably maximum of 2048 bytes are working with AG_LSEND/LRECV on S7-side, maybe two connections will be enough.

I remember that not all S5 CPU support datablocks with more than 255 words.
In the bigger S5-CPUs like CPU-928B there is a blockmove equivalent (OB182). The 115U should support TNB command, which allows you to copy up to 255 bytes en block.

 

[russg]

Hi Thomas,

Do you mean WITH multiplexing I can configure several SEND/RECEIVE connections? I have already tried to set up another connection without multiplexing and it wouldn't connect?

 

[Thomas_v2]

I meant several SEND/RECEIVE connections without multiplexing.
For example:
Connection 1 transfers DB100->DB100, DB101<-DB101
Connection 2 transfers DB110->DB110, DB111<-DB111

You have to check the manual of the CP on S5 and S7 how many connections they support.