用户程序存储器用于存放用户载入的PLC应用程序，载入初期的用户程序因需修改与调试，所以称为用户调试程序，存放在可以随机读写操作的随机存取存储器RAM内以方便用户修改与调试。
通过修改与调试后的程序称为用户执行程序，由于不需要再作修改与调试，所以用户执行程序就被固化到EPROM内长期使用。
PLC运行过程中需生成或调用中间结果数据(如输入/输出元件的状态数据、定时器、计数器的预置值和当前值等)和组态数据(如输入输出组态、设置输入滤波、脉冲捕捉、输出表配置、定义存储区保持范围、模拟电位器设置、高速计数器配置、高速脉冲输出配置、通信组态等)，这类数据存放在工作数据存储器中，由于工作数据与组态数据不断变化，且不需要长期保存，所以采用随机存取存储器RAM。
Siemens 6GK7243-2AX01-0XA0 Communciation Processor in Open Box KEV2
Honeywell UDC3300 DC330B-KEA0P Display CSQ
Allen Bradley Current Transformer Toroidal , CSQ
Rosemount 3051S2CG4A2E11A1A Pressure Transmitter CSQ
Allen Bradley 871L-B20E40-N3 Proximity Switch 20-250 VAC/DC in Bag CSQ
Allen Bradley 1336 SPK Drive Board, Rev 03, DSQ
Siemens D16 Power Control Board X2203 E1 37 67 949 CSQ
Siren Horn 31-DA 31DA 30 Watt NIOB tested CSQ KEV
Rexroth GS Hydraulic Valve CSQ
Fisher Rosemount Systems KJ4001X1-CA1 Rev. D I/O Terminal Block CSQ
AC Tech M3430BP MC Series Intelligent Drive 3 HP CSQ
Motorola GTX H11UCD6CB1AN Radio Mic Battery Charger Antenna BCK
Cutler Hammer FDB3020L Series C Circuit Breaker 20 Amps 3 Pole 6638C31G85 CSQ
Spectrum Controls AB 1746sc-IA8I 1746SCIA8I 8-Channel Isol. Input Module NNB CSQ
Omron E3G-L11 Photoelectric Switch 10-30 VDC in Open Box CSQ
SAIA UBD2408D25DUNNZ49 I-250 12V 2W Stepper Motor CSQ
Allen Bradley MPL-B320P-HK22AA AC Servo Motor ABY2
Emerson KJ1502X1-BE1 Power Supply 24VDC Din Rail FR3-1F KJ1502X1BE1 BCK
Flotect L4SS Float Switch 10AMP VAC CSQ
Mitsubisi FR-BU-H15K Brake Unit 800VDC 400V Class CSQ
Honeywell 1LS243 Micro Precision Limit Switch 600VAC NIOB BCK
Eaton IQ260MA65120 Meter Display 65A2036G10 CSQ
Cisco WS-C2924C-XL-EN Switch 2900 Series Catalyst WSC2924CXLEN BCK
Liquiflo M1S99EE0U030 High Pressure Gear Pump, 1GPM Flow Rate 1/2 discharge, CSQ
Mitsubishi A1S68DAI D/A Converter Unit 4-20mA CSQ
MTL 8112-DI-AC I/O Module 8 Channel DI 115 VAC Non Isolated 4-20mA CSQ
Siemens 3RV2011-1FA10 Motor Switch 3.5-5 Amp 3 Pole 3RV20111FA10 CSQ
Automation Direct EA7-S6M-R+09Y05B070 Operatior Interface BIC
GEC Alsthom ABB Brushless AC Servo Motor, LD825EJR2307, 3200 RPM, Used, WARRANTY
Allen Bradley 1585J-M8CBJM-0M3 Ethernet Patchcord Shielded in Bag BCK
Rosemount 2081C Analytical pH Transmitter 4-20mA 42.4 VDC Max CSQ
Cisco WS-C2950G-24-EL Catalyst Switch BCK
Allen Bradley 1756-M02AE /A ControlLogix 2 Axis Servo Module CSQ
GUARANTEED! GEC ALSTHOM PARVEX CURRENT MOTOR RX520KR1112
Cutler Hammer A10EG0 Nema Size 3 Starter Series A1 CSQ
Dayton 1EJN2 TIme Delay Relay 3A 230Vac AC12 NOS CSQ