Siemens SINUMERIK 828D Series Software And Hardware Service Manual page 240

Appendix
A.1 Abbreviations
RAM Random Access Memory: Program memory which can be read and written into
SI Safety Integrated
SLM Smart Line Module
SMC Cabinet-mounted sensor modules
SME Sensor Module External
S/R Steps per revolution: Pulses per revolution
SRAM Static Random Access Memory: Static memory (battery-backed)
NV SRAM Non-Volatile Static Random Access Memory: Non-volatile memory
USB Universal Serial Bus: Bus system for connecting additional devices to a computer
VDE Association of Electrical Engineering, Electronics and Information Technology (Germany)
240
Software and hardware
Service Manual, 08/2018, 6FC5397-5DP40-6BA1