Detailed Explanation of EM 235 Analog I/O Module
- انهيار رمز النموذج
| الجزء النموذجي | وصف |
| 6ES7 | Prefix for Siemens SIMATIC automation product مسلسل |
| 235 | Module type identifier: EM 235 analog input/output module |
| 0KD | كود المواصفات: 4 المدخلات التناظرية (منظمة العفو الدولية), 1 الإخراج التناظري (إلى), ±10V DC signal range |
| 22 | Hardware version number |
| 0XA0 | Standard version identifier (0XA8 is the China region version EM 235 CN) |
- المواصفات الفنية الأساسية
تحديد موضع المنتج: Expansion module for SIMATIC S7-200 series, only compatible with S7-22X CPUs (not compatible with S7-21X), spare part
I/O Configuration: 4 المدخلات التناظرية (منظمة العفو الدولية) + 1 الإخراج التناظري (إلى)
خصائص الإدخال:
Signal type: Differential input, ±10V DC (other ranges selectable via DIP switches)
دقة: 12 bits (بما في ذلك بت التوقيع)
Input impedance: ≥10MΩ (voltage input)
حماية الجهد الزائد: Up to 30V DC
خصائص الإخراج:
Signal type: ±10V DC (الجهد االكهربى) / 0-20 مللي أمبير (حاضِر, خياري)
دقة: 12 bits for voltage output, 11 bits for current output
Output impedance: ≤0.5Ω (voltage output)
Load capacity: Max 5mA for voltage output, max 20mA for current output
Power Requirements:
External supply: 24في العاصمة, max 60mA
Backplane bus: 5في العاصمة, max 30mA
Power dissipation: Typical 2W
Conversion Performance:
Input conversion time: <250ميكرو ثانية لكل قناة
Output response time: 1.5ms to 95% steady-state value
- بيئة التشغيل
- درجة حرارة التشغيل: 0–60°C (horizontal mounting), 0–40°C (vertical mounting)
- Storage temperature: -40–+85°C
- Relative humidity: 5–95% (غير التكثيف)
- فئة الحماية: IP20 (متوافق مع IEC 61131-2)
- تصاعد: تركيب السكك الحديدية DIN (compliant with EN 50022)
- Application scenarios:
Analog signal acquisition and control for small automation systems
Monitoring and regulation of process variables such as temperature, ضغط, and flow
Simple control loops requiring simultaneous analog input and output
- استبدال & Compatible Models
| نموذج | التوافق | ملحوظات |
| 6ES7 235-0KD22-0XA8 | Fully compatible | China version (EM 235 CN), same functions and parameters |
| 6ES7 231-0HC22-0XA0 | Input replacement | EM 231 4-channel analog input module (no output) |
| 6ES7 232-0HD22-0XA0 | Output replacement | EM 232 2-channel analog output module (no input) |
| S7-200 SMART EM AE04 | Upgrade replacement | For S7-200 SMART CPU, 4 المدخلات التناظرية; similar functions but not compatible with S7-22X |
- Official Ordering Information
Standard order number: 6ES7 235-0KD22-0XA0 (global version)
China order number: 6ES7 235-0KD22-0XA8 (EM 235 CN)
Product status: Currently a spare part for S7-200 system maintenance and replacement
- Key Usage Notes
- DIP switch settings: DIP switches on the side select input signal range; only one range can be set for the entire module
- برمجة:
Use Scale_I_to_R and Scale_R_to_I instructions in S7-200 software for analog/digital conversion
Analog input addresses: AIW0–AIW6 (2 bytes per channel)
Analog output address: AQW0 (2 bytes)
- Wiring rules:
Use shielded twisted-pair cable for analog signals, keep at least 10cm away from power cables
Unused channels should be shorted to avoid interference
- احتياطات:
Both external 24V DC and backplane 5V DC power must be connected
Hot swapping not supported; install/remove only with power off
- Comparison with S7-200 SMART Modules
| غرض | 6ES7 235-0KD22-0XA0 | S7-200 SMART EM AE04 |
| Compatible CPU | S7-22X series | S7-200 SMART series |
| I/O | 4AI/1AO | 4منظمة العفو الدولية |
| Signal range | ±10V / 0-20 مللي أمبير | Multiple options (including thermocouple/RTD) |
| تواصل | PPI protocol | PROFINET / Ethernet |
| Power supply | External 24V + backplane 5V | External 24V only |
Complete Model List of Siemens EM 235 Analog I/O Modules
- Core EM 235 Model Series (by hardware version)
| نموذج | HW Version | Region | وصف | Status |
| 6ES7 235-0KD00-0XA0 | 0 | Global | EM 235 analog combo module, 3AI/1AO, 12-bit | Discontinued, early version |
| 6ES7 235-0KD10-0XA0 | 10 | Global | EM 235 analog combo module, 4AI/1AO, 12-bit | Discontinued, transitional |
| 6ES7 235-0KD20-0XA0 | 20 | Global | EM 235 analog combo module, 4AI/1AO, 12-bit | Discontinued, legacy |
| 6ES7 235-0KD22-0XA0 | 22 | Global | EM 235 analog combo module, 4AI/1AO, 12-bit, S7-22X only | Spare, available |
| 6ES7 235-0KD22-0XA8 | 22 | CN (China) | EM 235 CN analog combo module, 4AI/1AO, 12-bit, S7-22X only | Spare, China-only |
- Detailed Model Differences
2.1 Common Features of All EM 235 Models
I/O: 4منظمة العفو الدولية + 1إلى (3منظمة العفو الدولية + 1AO for 00 version)
Input: ±10V DC (other ranges via DIP switches: 0-20 مللي أمبير, 4-20 مللي أمبير, mV)
الإخراج: ±10V / 0-20 مللي أمبير (4–20mA via wiring)
دقة: 12-bit input (with sign), 12-bit voltage output, 11-bit current output
التوافق: Only for S7-22X CPUs (not S7-21X)
2.2 الاختلافات الرئيسية
| غرض | 6ES7 235-0KD00-0XA0 | 6ES7 235-0KD22-0XA0/0XA8 |
| Analog inputs | 3 القنوات | 4 القنوات |
| DIP switches | Basic settings | Enhanced, supports more ranges |
| دقة | أساسي | Improved, better anti-interference |
| قوة | External 24V + backplane 5V | Same, optimized to 2W dissipation |
2.3 Global vs. China (CN) Version
6ES7 235-0KD22-0XA0: Global version, worldwide except China
6ES7 235-0KD22-0XA8: China-specific version; same functions and parameters, different certification and distribution
- Ordering & استبدال
3.1 Current Valid Part Numbers
Global: 6ES7 235-0KD22-0XA0 (spare)
China: 6ES7 235-0KD22-0XA8 (EM 235 CN, spare)
3.2 Upgrade Path to S7-200 SMART
| S7-200 Module | S7-200 SMART Replacement | اختلاف |
| EM 235 (4AI/1AO) | 6ES7 288-3AM03-0AA0 (2AI/1AO) | Fewer channels, وظائف محسنة, PROFINET/Ethernet |
| EM 235 (4AI/1AO) | 6ES7 288-3AM06-0AA0 (4AI/2AO) | More outputs, full feature upgrade |
- Important Operational Notes
- DIP switches: Set uniform measurement range for all AI channels
- Addressing:
Analog inputs: AIW0–AIW6 (2 bytes each)
Analog output: AQW0 (2 bytes)
- الأسلاك:
Shielded twisted-pair required; separate from power cables by ≥10cm
Short unused channels to reduce noise
- قوة: Both 24V DC external and 5V DC backplane required; no hot-swapping
The core models of the Siemens EM 235 analog I/O module are 6ES7 235-0KD22-0XA0 (global) and 6ES7 235-0KD22-0XA8 (China CN), both hardware version 22 spare parts for S7-22X CPU maintenance. Earlier versions (00/10/20) are discontinued. For system upgrades, use corresponding S7-200 SMART modules.
Siemens EM 235 (4 المدخلات التناظرية + 1 الإخراج التناظري)
is the most widely used analog mixed module for the S7-200 micro PLC.
Its core purpose: acquire multiple analog sensor signals and output one analog for closed-loop control.
It is designed for small-to-medium equipment, standalone automation, and local control systems, not large DCS systems.
Below is a complete list of applications by industry + typical control scenarios.
- General Closed-Loop Control Applications
- Constant Pressure Control
منظمة العفو الدولية: Pressure transmitter (4-20 مللي أمبير)
إلى: Inverter for pump/fan (0-10 فولت أو 0-20 مللي أمبير)
Uses: Constant pressure water supply, compressed air regulation, pipeline pressure stabilization
- Constant Temperature Control
منظمة العفو الدولية: Temperature transmitter, thermocouple/RTD
إلى: Electric control valve, سخان, electronic expansion valve
Uses: Water tank temperature control, small oven, HVAC unit, heat exchanger station
- Constant Level Control
منظمة العفو الدولية: Level transmitter (hydrostatic/ultrasonic)
إلى: Inlet control valve, variable-speed drainage pump
Uses: Water tank, reservoir, water tower, small storage tank level maintenance
- Flow & Metering Control
منظمة العفو الدولية: Electromagnetic flowmeter, turbine flowmeter
إلى: Control valve, metering pump, proportional valve
Uses: Batching systems, dosing, fluid proportioning
- Tension & Position Control
منظمة العفو الدولية: Tension sensor, displacement transducer
إلى: العاكس, proportional hydraulic valve
Uses: Constant tension in textile, printing, film, cable machinery
- Industry-Specific Applications
2.1 Water Supply & Wastewater Treatment
Small constant-pressure water supply systems
Sewage lift pumps, integrated wastewater treatment
Water tank level monitoring and auto refill
Pipeline pressure/flow monitoring and inverter control
2.2 التدفئة والتهوية وتكييف الهواء & Refrigeration
Chillers, air-cooled units
Fan coil units, air handling units
Heat exchanger station: primary/secondary water temp/pressure + valve control
Cooling tower fan speed control
2.3 Light Industry & Automation Machinery
التعبئة والتغليف, filling, sealing machines (level/weight control)
Small machine tools, الأنظمة الهيدروليكية (ضغط + proportional valve control)
Conveyor speed adjustment, material height detection
Food machinery: خلاطات, blenders, oven temperature control
2.4 Small Chemical & Batching Systems
Temperature and pressure monitoring for small reactors
Liquid batching and proportional mixing
Dosing systems: metering pump flow control
Tank level and temperature remote monitoring
2.5 Environmental Equipment
Bag filter differential pressure + fan control
Small desulfurization and denitrification regulation
Exhaust fan and spray pump control
2.6 Building Automation & Small Facilities
Building AHU and fresh air units
Ventilation pressure control in underground garages
Small heating and heat exchanger stations
2.7 Small Boilers & Heating Systems
Hot water boiler temperature, ضغط, level monitoring
Circulation pump variable-speed control
Analog control of burner damper/fuel valve
2.8 Hydraulic & Pneumatic Equipment
Hydraulic power unit pressure monitoring
Proportional pressure/flow valve control
Precision position control of pneumatic actuators
- Ideal Project Characteristics for EM 235
Small system: 1 وحدة المعالجة المركزية + few expansion modules
Requires 2–4 analog inputs and 1 analog control output
Compact space, cost-sensitive
Standard industrial signals: 0–10V / 0-20 مللي أمبير / 4-20 مللي أمبير
Single closed-loop control (temperature, ضغط, مستوى, tension)
- Summary of Typical Applications
The EM 235 is widely used in small automation machines, pump stations, HVAC units, constant-pressure water supply, and temperature control systems
where multi-channel analog acquisition plus single-channel analog closed-loop control is required.
المقاولين,قاطع الدائرة,العاكس للطاقة الشمسية,عداد كهرباء,البطاريات الشمسية



















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