Hi Guys,

I'm working with TSEND and TRCV blocks to read data from a modbus TCP Server(For learning purpose). In TRCV block, ADHOC is set TRUE and the value of LEN is set to 0. But I'm getting the error code 8088(The value at the LEN parameter is larger than the receive area set at the DATA parameter) when request is given. In the information system it's mentioned that for TCP connections ADHOC must be TRUE and LEN should be 0. Then what's the reason for the error? Is there anything I'm missing???. Attached the structure of receive area (The same one used inside MB_Client). Thanks in Advance.

Hello,

from your description is not clear to me what parameters and for what exactly memroy areas you asking help. Give us some screenshots from your comm blocks, online values to see and also your memory area for data receive. I expect also optimized access option to see where exactly on which block you mention. ZIP them, attach and describe your idea better.

Update: just one very important thing. You didn't specify your exact HW CPU type and SW what can have big different effect on your functionality. Without to describe all things better, no good help can be provided.

Hi Duris,

I'm using TSEND and TRCV blocks to read data from a modbus server. In TRCV block, I want to give a memory area from an optimized block as DATA (InOut Variable of the TRCV block).I'm using the same structure used inside MB_Client block to send and receive data(Please find it in the attachment, and the DB in which these structures is a DB with optimized block access. I've set ADHOC TRUE and LEN to 0. But when the receive request is given I'm getting an error status of 16#8088. Please find the attachments, the program also is included for your reference.

Hello,

on other side you looks like missunderstanded that error description due your block functionality, I can tell you that I have also receive DB also with optimized access and all is functional without problems with Adhoc. Your error means that you have defined some length of buffer but your recived data are bigger than your buffer. This message can be understanded with also different meaning and this depends to your defined LEN parameter, as overwrited buffer with maybe short amount of data

Hi,

The maximum data I'm trying to read is 12 registers, that is 24 bytes. If you look at the structure of the receive variable in my DB , the total size is 259 bytes, then how the receive area will be smaller than the LEN parameter (May be I've misunderstood the parameter) . But If I remove the optimized access... KABOOM, It will start working without any error.

Hello,

because you have there 2 LEN parameters, one as Input and one as Output parameter

heh ok no problem here because you can see clearly again see my description about use of Optimized access without problems. And again as I said, all depends to exact CPU type version and TIA SW used with blocks versions

Hi Duris,

The following is my understanding, Please correct me if it's wrong

1. We have one LEN parameter as input to TSEND block in which we have to mention the amount of data being sent to the server, So including Transcation ID(2 Bytes), Protocol ID(2 Bytes), Length(2 Bytes), Unit Identifier(1 Byte), Function code (1 Byte), Start Address (2 Bytes) and quantity(2 Bytes) the total size should be 12 Bytes.

2. We have another LEN parameter as input to TRCV block which should be zero in my case since ADHOC is enabled.

3. Then there is another parameter RCVD_LEN where actual received length will be shown

If the above are correct, what is it I'm missing which is causing the error ??

Hello,

ok, I try ask again for 3-rd time???? what is your exact CPU type, SW used and blocks versions. Yes, maybe I was not so clear about that LEN as recv parameter (output) but this is for what I've tried put your attention to this. Simply said, if you define wrongly Adhoc as LEN parameter or you have due this parameter wrongly defined recv area, you'll have not correct data. Be carefull, you can have success temporary but all depends if your buffer is filling asevery new message as 0-th offset or is added to existed previously received data(last element+1 offset) data field. Then you can have after while (all depends to your long message received) overfilled buffer again. Simply you need understand what you really do and have all tests closed with correct results.

Hi Duris,

Pardon me, I forgot the version part

I'm using CPU 1214C DC/DC/DC (6ES7 214-1AG40-0XB0), Firmware version 4.5

TIA V17

TSEND - V4.0

TRCV - V4.0