Using PROFINET Record Data

PROFINET defines Record Data in addition to the cyclic I/O data exchange. The PLC can read or write these records using RDREC and WRREC or similar function blocks. Each data record within a PROFINET device is addressed through the Slot, Subslot, and Index. The RMC supports three types of data records: fixed, custom, and PROFINET-specific. Only the first two are typically of interest to RMC users.

PROFINET allows the caller to specify the length of the data being read, but does not specify a starting offset within the given data record. Therefore, the PLC can only read or write starting at the beginning of a data record. The RMC75 and RMC150 maximum read/write length per record is 2048 registers (8,192 bytes). The RMC200 maximum read/write length per record is 4096 registers (16,384 bytes).

RMC75 and RMC150 Data Records

The RMC75 and RMC150 have many pre-defined data records and four configurable data records.

The records limit you to read and write starting at the beginning of each defined range. Each read or write of an RMC75 or RMC150 data record can be up to 2048 registers (8,192 bytes).

Fixed Data Records

The RMC75 and RMC150 define one data record for each RMC register file with the index of each match the number of the register file. Fixed data records are addressed as Slot 0, Subslot 1, and Index of 7-255:

Index	Starting Address	Description
7	%MD7.0	Contents of RMC register file 7
8	%MD8.0	Contents of RMC register file 8
:	:	:
255	%MD255.0	Contents of RMC register file 255

For a list of the register files and their content see the RMC75 Register Map or the RMC150 Register Map.

Notice that because PROFINET always starts its reads and writes at the beginning of the data record, fixed data records can only be used to read or write starting at the beginning of an RMC register file. Custom Data Records get around this limitation.

Custom Data Records

In order to allow users to read and write registers in the RMC starting at locations other than the beginning of a register file, the RMC75 and RMC150 define four Custom Data Records, which are addressed as Slot 0, Subslot 1, and Index 1000-1003:

Index	Starting Address	Description
1000	Configurable	The starting address is configurable in RMCTools.
1001	Configurable	The starting address is configurable in RMCTools.
1002	Configurable	The starting address is configurable in RMCTools.
1003	Configurable	The starting address is configurable in RMCTools.

The starting addresses of each of the Custom Data Records are set up in the PROFINET Settings Page.

For example, to read or write a block of registers starting at variable 50 (%MD56.50), the user can set Custom Data Record 1000 to have a starting address of %MD56.50, and then read or write to Index 1000.

RMC200 Data Records

Use the PROFINET Data Records Address Map to view and configure the RMC200 Data Records. Data records 0-3 are pre-defined and you can configure up to 128 additional data records to access registers in the RMC200.

The records limit you to read and write starting at the beginning of each defined range. Each read or write of an RMC200 data record can be up to 4096 registers (16,384 bytes).

Fixed Data Records

The following RMC200 data records are fixed:

Index	Starting Address	Register Count	Description
0	%MD8.0	256	Indirect Data Map
1	%MD16.0	1280	Command Area
2	%MD1024.0	256	Variables 0-255
3	%MD23.0	4096	Image Upload/Download Area

Adding Data Records

In the bottom row, in the Start Address column, enter the data record number you wish to use. The data record number must be a whole number between 4.0 and 32767.0, with a decimal point and a zero. The first number, before the decimal point, is the Record Index. The second number, after the decimal point, is the starting register offset within the data record, which must be zero. For example, 4.0 or 100.0.
In the Registers column, enter the number of registers. This is the number of 32-bit registers in the RMC.
In the Map To column, enter the area in the RMC that this address range will apply to.
Repeat for additional data records. The rows will automatically re-order entries to keep them in numerical address order.
Click the Download button to download the changes to the RMC.

PROFINET-specific Record Data

In addition to the user data records described above, the RMC also supports PROFINET-specific data records as defined in the PROFINET standard. These records are generally only of interest to the PROFINET configuration software. They have Index values in the range of 0x8000-0xFFFF. Refer to the PROFINET specification for details.

Record Data Format and Length

The contents of the Fixed and Custom Data Records match the contents of the corresponding RMC registers. Therefore, each register will be a 32-bit (4-byte) DINT, DWORD, or REAL data value. However, be aware that the MLEN and LEN parameters on the RDREC and WRREC function blocks are in bytes. Therefore, these values must be 4x the number of registers you want to read or write. By default each 32-bit value is transmitted most-significant byte first, which should work for most IO controllers. Otherwise, the byte order can be changed to least-significant byte first on the PROFINET Settings Page.

The RMC75 and RMC150 maximum read/write length per data record is 2048 registers (8,192 bytes). The RMC200 maximum read/write length per data record is 4096 registers (16,384 bytes).