Siemens S7-1200 PROFIBUS - Performance Data; Requirements for Operation

Application and properties
1.3 Performance data
SIMATIC CM 1242-5
10 Operating Instructions, 01/2023, C79000-G8976-C245-06
Types of communication with the CM 1242-5 in DP-V1
The following types of communication are available with DP-V1:
• Cyclic communication
The CM supports cyclic communication for the transfer of process data between DP slave
and DP master.
Cyclic communication is handled by the operating system of the CPU. No software blocks
are required for this. The I/O data is read or written directly from/to the process image of
the CPU.
Reading out identification data
With data record 255 (index 65000 to 65003), according to the DP-V1 specification, the
identification data I&M 0 can be read out.
You will find information on the data structure in the PROFIBUS Profile Guideline, Part 1,
V1.1.1, order number 3.502.
1.3 Performance data
Number of CPs/CMs that can be plugged in per S7-1200 station
You can configure a maximum of three CMs/CPs per station, in other words, 3 DP slave
modules (CM 1242-5).
Transmission speeds of the CM 1242-5
As the transmission speed on PROFIBUS, values of 9.6 kbps to 12 Mbps are permitted for the
CM.
Characteristic data of the DP interface of the CM 1242-5
Maximum size of the DP data areas of the DP slaves
• Input area per DP slave: Max. 240 bytes
• Output area per DP slave: Max. 240 bytes
1.4 Requirements for operation
Configuration tool
To configure the CM, the following configuration tool is required:
STEP 7 Basic as of version V11 SP2 Update 2