Hi everyone,

I've got a Modbus TCP/IP communication problem on a S7-1200 and a SMA Cluster controller. The S7-1200 give me an error code 8381.

I want to access data in an SMA inverter, connected to the cluster controller (SPeedwire communication is OK.

My network can be describe bellow :

S7-1200 (IP10.228.33.172) -->Cluster controlller (IP10.228.33.171   ID:1)-->Inverter (same IP  ID:3)

I configure my MB_CLIENT on S7-1200

My Modbus server on the Cluster controller is activated (good IP, submask, port number)

I try to communicate like bellow, with the same parameters :

S7-1200 to another S7-1200 -->OK

Modbus doctor to Cluster Controller -->OK

Multiway to cluster controller --> OK

But there is no way to make work the communication between S7-1200 and the Cluster controller !

I also try to parameterize the MB_UNIT_ID to 1 or 3, To write the same ID_Connection and MB_UNIT_ID etc. but it still doesn't work.

Please Help me ;)

Hello,

the error code is explained in the information system of TIA (F1 button).  The function code is not correct which is part of MB_MODE and MB_DATA_ADDR. Please check these two parameters.

We checked the data frame with Multiway software. The adress code sended by the S7-1200 is not the same as our entry.

The MB_CLIENT data block (V3.1) remove the first Digit of 4xxx2, and minor 1.

For exemple, if i write 40002, the data frame will contain 0001 in the adress field. The Modbus salve doesn't understand the frame et generate an error.

I gonna try with the V4.0 MB_CLIENT version. I hope I could access to the adress corrected by the MB_CLIENT block.

But first of all, I have to update the firmware of the CPU to V4.1. that's an another problem because the firmware sended by Siemens could not being selected by TIA Portal or by the web server (there is no extension in the file !)

I will wrote later. I hope it coulb help someone.

New question published by kyloivn is split to a separate thread with the subject Can't read the true values from Holding Register.

Best regards
Min_Moderator

Good afternoon!

I faced the same problem, also with SMA cluster controller. Did the update to V.4.0 help you to solve this problem?

Hi,

When looking at your screendump it seems that you have put in the IP-adress in wrong order. As you have it in the block I guess it will be 10.33.228.171

Ubbe

ip_OCTET_2 AND ip_OCTET_3  shall be exchange  according of  server ip