Entry type: FAQ, Entry ID: 58378237, Entry date: 11/26/2014
(0)
Rate

Which blocks for Modbus TCP can you rename or re-wire when the block numbers of the Modbus blocks are already being used in the user program?

  • Entry
  • Associated product(s)

Description
The blocks that are available for Modbus communication with SIMATIC S7 are delivered with a unique block number.
If there are already blocks in the user program that have these block numbers, there is a block number conflict.

Please proceed as follows to avoid this conflict.

  • You can rename the Modbus blocks that are called directly in the user program.
  • You cannot rename the blocks that are called internally in the Modbus blocks. You have to re-wire those blocks.

The table below shows the Modbus blocks that you can rename or re-wire.
 

Product Article no. Modbus block > rename Block called internally from the Modbus library > re-wire Block called internally from the Standard / SIMATIC NET library > re-wire
Modbus/TCP CP 2XV9450-1MB00 FB108 FB106, FB107 AG_(L)SEND
AG_(L)RECV
EQ_STRNG(*)
AG_CNTRL(**)
Modbus/TCP RED V2 2XV9450-1MB11 FB909, FB907 FB908, FB906 AG_(L)SEND
AG_(L)RECV
EQ_STRNG(*)
AG_CNTRL(**)
Modbus/TCP PN CPU 2XV9450-1MB02 FB102 FB103, FB104, FB105 TSEND
TRCV
TCON
TDISCON
EQ_STRNG(*)
Modbus/TCP PN CPU Redundant 6AV6676-6MB10-0AX0 FB915, FB917 FB913, FB914, FB916 TSEND
TRCV
TCON
TDISCON
Modbus/TCP SENTRON PAC 6AV6676-6MA30-0AX0
6AV6676-6MA30-1AX0
6AV6676-6MA30-2AX0
FB109, FB110, FB111 FB99, FB103, FC99 TSEND
TRCV
TCON
TDISCON
TUSEND
Table 01

(*) The EQ_STRNG block is only in older versions of the product.
(**) If both EQ_STRNG and AG_CNTRL are used by the Modbus blocks are used, then AG_CNTRL is already re-wired in the Modbus library. More information about this is available in the relevant product manual.

You must follow a specific order when re-wiring the blocks that are called internally in the Modbus blocks. Re-wire the blocks - if necessary - in the order listed.

  1. EQ_STRNG, AG_CNTRL, AG_(L)SEND, AG_(L)RECV, TSEND, TRCV, TCON, TDISCON
  2. Internally called blocks (FB106, FB107, FB1734, FB908, FB906, FB103, FB104, FB105, FB913, FB914, FB915, FB99, FB103, FC99)
  3. Remaining blocks

You do not have to re-wire all the blocks. Even if you re-wire only a few internally called blocks, you must nevertheless keep to the order given above. In this case, you leave out the blocks that are not re-wired.

Error details
Detailed error description
Error status code
500
Error ID in event log
98961426
Help us to improve Online Support.
The page requested cannot be displayed. Please contact the webmaster.
Contact to webmaster