Appendix model variants 21 process image 28, 37 modular programming 146 processor 31 module hierarchy 67 program module 66 modules programming 65 programmable clock 120 programmable counter commands 62 NAND 93 negation programmable pulse commands 62 at input 92 programmable timer commands 62 at output 92 NOR 93 notes 14 project planning 15 NV-RAM 33 raising delay 115 On-chip RAM 31 RD_OFFS 85 receive single character 77 operand ranges 43 Reliability 13 operands resistance to interference 17 set functions 46 summary 45 retrievability 32 types 48 safety 15 operating system 31 seal-in circuit 95 send single character 76 operative approach 35 send strings 78 OR 91 OR marker 100 sequential process 123 order specifications 162 servicing 16 organisation module 66 shift commands 56 shift register 125 overload 29 short circuit 29, 153 PLC cycle 36 Software 35 power supply 27, 29 outputs 29 software counters 121 system 27 SST667IN 78 target group 13 164