Siemens Simatic S7-300 CPU 31xC and CPU 31x S7-300 - Manual (Page 8)

Table of contents
CPU 31xC and CPU 31x, Technical data
viii
Manual, Edition 08/2004, A5E00105475-05
4 Memory concept ..................................................................................................................................... 4-1
4.1 Memory areas and retentivity..................................................................................................... 4-1
4.1.1 CPU memory areas.................................................................................................................... 4-1
4.1.2 Retentivity of the load memory, system memory and RAM....................................................... 4-2
4.1.3 Retentivity of memory objects.................................................................................................... 4-3
4.1.4 Address areas of system memory ............................................................................................. 4-5
4.1.5 Properties of the Micro Memory Card (MMC)............................................................................ 4-9
4.2 Memory functions..................................................................................................................... 4-11
4.2.1 General: Memory functions...................................................................................................... 4-11
4.2.2 Loading user program from Micro Memory Card (MMC) to the CPU ...................................... 4-11
4.2.3 Handling with modules............................................................................................................. 4-12
4.2.3.1 Download of new blocks or delta downloads........................................................................... 4-12
4.2.3.2 Uploading blocks...................................................................................................................... 4-12
4.2.3.3 Deleting blocks......................................................................................................................... 4-13
4.2.3.4 Compressing blocks................................................................................................................. 4-13
4.2.3.5 Promming (RAM to ROM)........................................................................................................ 4-13
4.2.4 CPU memory reset and restart ................................................................................................ 4-13
4.2.5 Recipes .................................................................................................................................... 4-15
4.2.6 Measured value log files .......................................................................................................... 4-17
4.2.7 Backup of project data to a Micro Memory Card (MMC) ......................................................... 4-19
5 Cycle and reaction times......................................................................................................................... 5-1
5.1 Overview .................................................................................................................................... 5-1
5.2 Cycle time................................................................................................................................... 5-2
5.2.1 Overview .................................................................................................................................... 5-2
5.2.2 Calculating the cycle time .......................................................................................................... 5-5
5.2.3 Different cycle times................................................................................................................... 5-8
5.2.4 Communication load .................................................................................................................. 5-9
5.2.5 Cycle time extension as a result of testing and commissioning functions ............................... 5-11
5.2.6 Cycle extension through component-based automation (CBA)............................................... 5-11
5.3 Response time ......................................................................................................................... 5-14
5.3.1 Overview .................................................................................................................................. 5-14
5.3.2 Shortest response time ............................................................................................................ 5-16
5.3.3 Longest response time............................................................................................................. 5-17
5.3.4 Reducing the response time with direct I/O access................................................................. 5-18
5.4 Calculating method for calculating the cycle/response time.................................................... 5-19
5.5 Interrupt response time ............................................................................................................ 5-21
5.5.1 Overview .................................................................................................................................. 5-21
5.5.2 Reproducibility of delay interrupts and watchdog interrupts .................................................... 5-23
5.6 Sample calculations ................................................................................................................. 5-24
5.6.1 Example of cycle time calculation ............................................................................................ 5-24
5.6.2 Sample of response time calculation ....................................................................................... 5-25
5.6.3 Example of interrupt response time calculation ....................................................................... 5-27
6 Technical data of CPU 31xC................................................................................................................... 6-1
6.1 General technical data ............................................................................................................... 6-1
6.1.1 Dimensions of CPU 31xC .......................................................................................................... 6-1
6.1.2 Technical data of the Micro Memory Card (MMC)..................................................................... 6-2
6.2 CPU 312C .................................................................................................................................. 6-3
6.3 CPU 313C .................................................................................................................................. 6-8
6.4 CPU 313C-2 PtP and CPU 313C-2 DP ................................................................................... 6-14