Siemens 6ES7223-1PL22-0XA0 EM223 I/O Module

The Siemens 6ES7223-1PL22-0XA0 (EM223) is a digital I/O expansion module for the SIMATIC S7-200 programmable logic controller family. This compact module provides 16 digital inputs and 16 digital relay outputs in a single unit, delivering a total of 32 I/O points. The EM223 is designed to work exclusively with S7-22X CPUs (S7-221, S7-222, S7-224, S7-226, S7-224XP) and is installed by connecting to the right side of the CPU or existing expansion modules. It is ideal for expanding the I/O capacity of S7-200 systems in small to medium automation projects.

Technical Specifications

The EM223 features 16 digital inputs, each accepting 24 V DC (sink/source configurable). Input voltage range for signal "0" is 0 to 5 V DC; for signal "1" is 15 to 30 V DC. Typical input current at 24 V DC is 4 mA. Input delay for standard inputs from "0" to "1" is 4.5 ms max. The module provides 16 relay outputs, each rated at 2 A per channel (maximum 8 A per common group). Relay outputs can switch either DC or AC loads: load voltage L1 is rated at 230 V AC (permissible range 24 V AC to 230 V AC) or 24 V DC (permissible range 5 V DC to 30 V DC). Output voltage for signal "0" is 0.1 V max (with 10 kΩ load). Relay outputs are isolated by design, with no short-circuit protection (external fuses required). The module draws 72 mA from the external 24 V DC supply and 150 mA from the backplane 5 V DC bus. Power loss is 6 W typical. The EM223 includes one RS-485 communication port for connecting to the CPU's expansion bus. Dimensions: 80 mm (H) × 137.5 mm (W) × 62 mm (D). Weight: 0.4 kg. Operating temperature: 0°C to 55°C. Storage temperature: -40°C to 70°C. Humidity: 5-95% non-condensing. Protection rating: IP20.

Key Features

• 16 digital inputs (24 V DC, sink/source configurable)

• 16 digital relay outputs (2 A per channel, 5-30 V DC or 24-230 V AC)

• Total of 32 I/O points in a single expansion module

• Compatible only with S7-22X CPUs (S7-221 to S7-226)

• Relay outputs suitable for both AC and DC loads

• Galvanic isolation for both inputs and outputs

• DIN rail mounting or direct panel mounting

• Removable terminal blocks for convenient wiring

• CE, UL, CSA certified

Input and Output Characteristics

The 16 digital inputs are arranged in two groups of 8 inputs. Each group shares a common return (M) terminal. Inputs can be wired as sink (current flowing into the input from a PNP sensor) or source (current flowing out of the input to an NPN sensor) by connecting the common accordingly. Input LED indicators illuminate when the input is active (24 V DC present). The 16 relay outputs are arranged in four groups of 4 outputs (2 groups for outputs 0-7 and 2 groups for outputs 8-15). Each group is isolated and has its own common terminal (L1 and M for AC switching, or L+ and M for DC switching). Relay output LED indicators illuminate when the output coil is energized. The relay outputs have a mechanical life of 10 million operations and an electrical life of 100,000 operations at rated load. Outputs are not short-circuit protected; external fuses or circuit breakers are required for each output or each output group.

Compatibility and Expansion

The EM223 is designed for use with Siemens SIMATIC S7-200 series CPUs including S7-221, S7-222, S7-224, S7-226, and S7-224XP. It attaches to the CPU via the built-in expansion connector on the right side of the CPU. Multiple expansion modules can be chained together; the maximum number of expansion modules depends on the CPU model (typically 2 to 7 modules). The module is not compatible with newer S7-1200 or S7-1500 series PLCs. It is a legacy product for maintaining existing S7-200 installations. The module is configured automatically by the CPU; no additional software configuration is required beyond assigning I/O addresses, which are automatically allocated in the order of module connection.

Applications

The EM223 is used to expand the I/O capacity of S7-200 systems for applications such as packaging machinery, conveyor control, small machine tools, pump and fan control, material handling equipment, and building automation. The relay outputs are suitable for controlling contactor coils, solenoid valves, indicator lamps, and small motors. The 16 inputs can interface with pushbuttons, limit switches, proximity sensors, and photoelectric sensors. The module provides a cost-effective way to add mixed I/O capability when both digital inputs and outputs are needed in approximately equal numbers.

Installation and Wiring

Mount the EM223 on a 35 mm DIN rail (EN 60715) or directly to the panel using the optional mounting feet. Connect the expansion ribbon cable from the previous module (or CPU) to the EM223's expansion connector. For the first module, connect to the CPU; for subsequent modules, connect to the previous module's output connector. Wire the 24 V DC power supply to the L+ and M terminals on the module (required for input circuits). For inputs, connect sensors between the input terminal and the common terminal (M). For relay outputs, connect the load between the output terminal and the load supply (L1 or L+ depending on voltage). Use separate fuses for each output group. Ensure that relay contact ratings are not exceeded (2 A per output, 8 A per common). The module includes removable terminal blocks to facilitate replacement without rewiring.

Maintenance and Troubleshooting

The EM223 is maintenance-free. LED indicators provide diagnostic information: the PWR LED indicates that the module is receiving 5 V DC from the backplane. Input LEDs (0-15) illuminate when the corresponding input is active. Output LEDs (0-15) illuminate when the corresponding relay coil is energized. If an output fails to energize, check the output LED; if it is illuminated but the load does not turn on, check the relay contacts and load wiring. The module has no replaceable internal fuses; external overcurrent protection is required. Relay contacts may wear over time with high switching frequencies; periodic replacement may be necessary for very high-cycle applications.

Environmental and Compliance

The EM223 is CE, UL, and CSA certified. It is RoHS compliant. Operating temperature: 0°C to 55°C. Storage temperature: -40°C to 70°C. Humidity: 5-95% non-condensing. Protection rating: IP20 (requires installation in a control cabinet).

Conclusion

The Siemens 6ES7223-1PL22-0XA0 EM223 digital I/O module provides a convenient way to expand the I/O count of S7-200 systems with 16 inputs and 16 relay outputs. Its mixed I/O configuration, relay output flexibility, and plug-and-play installation make it a practical choice for maintaining legacy S7-200 installations requiring additional I/O points.