The SM 1223 (6ES7 223-1PH32-0XB0) is a robust, compact digital I/O module designed for seamless integration with the SIMATIC S7-1200 PLC family. It offers a balanced blend of 8 digital inputs (24 V DC, sink/source) and 8 relay outputs (dry contact, 2 A)—a reliable solution for discrete signal interfacing in automation environments.
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Technical Specifications
Dimensions & Mechanical

Form Factor: Compact size, 45 × 100 × 75 mm (W × H × D); weight approximately 230 g
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Protection Class: IP20, standard DIN-rail module construction
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Power & Consumption

Backplane Supply:

From SM-Bus (5 V rail): ~145 mA
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Input Current:

~4 mA per digital input

~11 mA per activated relay coil
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Power Dissipation: Typ. about 5.5 W
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Digital Inputs (DI)

Quantity & Type: 8 × 24 V DC, sink/source configuration (IEC Type 1 sink)
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Voltage Ratings:

Nominal: 24 V DC at ~4 mA

Max permissible: 30 V DC (withstanding up to 35 V for 0.5 sec)
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Signal Thresholds:

Logic “1” (min): 15 V DC at 2.5 mA

Logic “0” (max): 5 V DC at 1 mA
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Input Delay: User-selectable filtering at 0.2, 0.4, 0.8, 1.6, 3.2, 6.4, and 12.8 ms (in groups of four)
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Cable Length:

Shielded cable: up to 500 m

Unshielded: up to 300 m
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Digital Outputs (DO)

Quantity & Type: 8 × relay outputs (mechanical dry contacts), 2 A max per contact
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Operating Voltage Range: 5–30 V DC or 5–250 V AC
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Capacities:

Resistive load: 2 A

Lamp load: max. 30 W (DC) or 200 W (AC)
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Switching Delay: Max 10 ms from “0” to “1” or vice versa
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Electrical Isolation

DI & DO to Logic: 1,500 V AC isolation between field side and logic/backplane
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Between Channels: Grouped isolation—ensuring separation for safety and signal integrity
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Diagnostics & Indicators

On-board LEDs indicate status of inputs, outputs, and maintenance flags for efficient system monitoring
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Integrated diagnostic alarms and status feedback
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Environmental Ratings

Operating Temperature:

Horizontal mounting: –20 °C to +60 °C

Vertical mounting: –20 °C to +50 °C
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Storage & Transport: –40 °C to +70 °C; humidity up to 95 %, non-condensing including altitude variants
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Other Mechanical Conditions: Withstands short free-fall of up to 0.3 m during packaging/shipping
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Certifications & Compliance

Certified for industrial use under CE, UL/cULus, CSA, FM, RCM, KC, and Marine safety standards
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Engineering Highlights

High I/O Density, Compact Footprint: Integrates 8 digital inputs and outputs within a small 45 mmwide module—ideal for space-constrained control panels.

Flexible Signal Behavior: Sink/source DI configuration and hardware-filtering options guard against signal noise and sensor variability.

Long Cable Support: Accommodates remote I/O installations with cable runs up to 500 m, reducing potential field wiring limitations.

Robust Relay Outputs: Dry contact relays rated for both AC and DC loads offer flexibility across diverse actuation scenarios.

Strong Isolation & Safety: High-voltage isolation ensures protection between field devices and PLC logic systems.

Engineered for Diagnostics & Maintenance: LED indicators and alarms streamline needed fault detection and system response.

Typical Applications

Machine Control Systems: Driving relays, indicator lights, and processing discrete sensor signals.

Distributed Automation: Extending I/O across machinery or sites with long cable wiring.

Retrofit Projects: Adding discrete interfaces cleanly to existing S7-1200 systems.

Harsh Industrial Environments: Tolerant temperature range and strong isolation make it reliable for heavy-duty applications.

Summary Table
Category Specification
Digital Inputs (8) 24 V DC, sink/source, user-selectable delays
Digital Outputs (8) Relay outputs, 2 A, 5–30 V DC / 5–250 V AC
Power Draw ~145 mA from SM-Bus; ~4 mA (DI), ~11 mA (DO)
Power Loss Approx. 5.5 W
Isolation Voltage 1,500 V AC between field and logic
Dimensions & Weight 45 × 100 × 75 mm; ~230 g
Certifications CE, UL/cULus, CSA, FM, RCM, KC, Marine
Diagnostics LEDs for I/O status and maintenance alerts