Siemens Simatic S7 Series System Manual

Table of contents
S7-200 SMART
10 System Manual, 09/2015, A5E03822230-AC
8.6 RS485 .................................................................................................................................. 395
8.6.1 PPI protocol .......................................................................................................................... 395
8.6.2 Baud rate and network address ........................................................................................... 396
8.6.2.1 Definition of baud rate and network address ....................................................................... 396
8.6.2.2 Setting the baud rate and network address for the S7-200 SMART CPU ........................... 397
8.6.3 Sample RS485 network configurations ................................................................................ 399
8.6.3.1 Single-master PPI networks ................................................................................................. 399
8.6.3.2 Multi-master and multi-slave PPI networks .......................................................................... 399
8.6.4 Building your network ........................................................................................................... 400
8.6.4.1 General guidelines ............................................................................................................... 400
8.6.4.2 Determining the distances, transmission rates, and cable lengths for your network ........... 401
8.6.4.3 Repeaters on the network .................................................................................................... 401
8.6.4.4 Selection of the network cable ............................................................................................. 402
8.6.4.5 Connector pin assignments ................................................................................................. 402
8.6.4.6 Biasing and terminating the network cable .......................................................................... 403
8.6.4.7 Biasing and terminating the CM01 signal board .................................................................. 405
8.6.4.8 Using HMI devices on your RS485 network ........................................................................ 405
8.6.5 Freeport mode ...................................................................................................................... 406
8.6.5.1 Creating user-defined protocols with Freeport mode ........................................................... 406
8.6.5.2 Using the RS232/PPI Multi-Master cable and Freeport mode with RS232 devices ............ 409
8.7 RS232 .................................................................................................................................. 410
9 Libraries ................................................................................................................................................. 411
9.1 Creating a user-defined library of instructions ..................................................................... 411
9.2 USS library instructions ........................................................................................................ 413
9.2.1 USS communication overview ............................................................................................. 413
9.2.1.1 USS protocol overview ......................................................................................................... 413
9.2.1.2 Requirements for using the USS protocol ........................................................................... 414
9.2.1.3 Calculating the time required for communicating with the drive .......................................... 415
9.2.2 USS program instructions .................................................................................................... 416
9.2.2.1 Using the USS protocol instructions .................................................................................... 416
9.2.2.2 USS_INIT instruction ............................................................................................................ 417
9.2.2.3 USS_CTRL instruction ......................................................................................................... 419
9.2.2.4 USS_RPM_x instruction ....................................................................................................... 422
9.2.2.5 USS_WPM_x instruction ...................................................................................................... 425
9.2.2.6 USS protocol execution error codes .................................................................................... 428
9.2.2.7 USS protocol example program ........................................................................................... 429
9.3 Modbus library instructions .................................................................................................. 431
9.3.1 Modbus communication overview ........................................................................................ 431
9.3.1.1 Modbus library features ....................................................................................................... 431
9.3.1.2 Initialization and execution time for Modbus protocol .......................................................... 433
9.3.1.3 Modbus addressing .............................................................................................................. 434
9.3.2 Modbus RTU master ............................................................................................................ 436
9.3.2.1 Using the Modbus master instructions ................................................................................. 436
9.3.2.2 MBUS_CTRL instruction (initialize master) .......................................................................... 437
9.3.2.3 MBUS_MSG instruction ....................................................................................................... 438
9.3.2.4 Modbus master execution error codes ................................................................................ 442
9.3.3 Modbus RTU slave .............................................................................................................. 443
9.3.3.1 Using the Modbus slave instructions ................................................................................... 443
9.3.3.2 MBUS_INIT instruction (initialize slave) ............................................................................... 445
9.3.3.3 MBUS_SLAVE instruction .................................................................................................... 446

Siemens Simatic S7 Series Specifications

General

CPU	Varies by model (e.g., S7-300, S7-400, S7-1200, S7-1500)
Communication Interfaces	PROFIBUS, PROFINET, Ethernet, MPI
Programming	TIA Portal, STEP 7
Programming Languages	LAD, FBD, STL, SCL, GRAPH
I/O Modules	Digital, Analog, Specialty modules available
Operating Temperature	0°C to 60°C (standard models)
Mounting	DIN rail mounting
Operating Voltage	24V DC or 120/230V AC (varies by model)
Protection Class	IP20 (standard models)
Memory	Varies depending on the S7 model. Includes work memory (RAM) for program execution, load memory (EEPROM or Flash) for program storage, and system memory for operating system functions. Memory sizes range from kilobytes to megabytes.