Siemens S7-200 SM 222 Modules – 6ES7222-1HF22-0XA0

Technical Dossier

Product Details And Specifications

Siemens S7-200 SM 222 Series Technical Notes

The Siemens S7-200 is a compact, fixed-architecture programmable logic controller platform that has been deployed across global heavy industry since the mid-1990s. Its signal module (SM) expansion range — including the SM 221 digital input, SM 222 digital output, SM 223 combined DI/DO, SM 231 analog input, SM 232 analog output, and SM 235 analog combined modules — forms the backbone of discrete and process control installations in chemical plants, oil refineries, water treatment facilities, and nuclear auxiliary systems worldwide. The 6ES7222-1HF22-0XA0 is a representative SM 222 relay output module within this ecosystem: 8 relay outputs, 2 A per point, rated for 24 VDC or 250 VAC loads, housed in the standard S7-200 expansion form factor. As of 2015, Siemens officially discontinued the S7-200 platform in favor of the S7-1200 and S7-200 SMART lines; however, the installed base remains extensive, and lifecycle spare part sourcing is an active requirement for maintenance engineers globally.

The Evolution of S7-200 SM 222 Architecture

The S7-200 platform was introduced by Siemens in 1994 as a successor to the S5-90U/95U micro-PLC range. The SM 222 digital output module family evolved through two primary hardware revisions: the early 21x-series (e.g., 6ES7222-1BF00-0XA0) with 24 VDC transistor outputs, and the later 22x-series (e.g., 6ES7222-1HF22-0XA0) with relay contact outputs suitable for mixed AC/DC load switching. The expansion bus uses a proprietary 34-pin edge connector; modules are not electrically compatible with S7-300, S7-400, or S7-1200 backplanes. Migration to S7-1200 requires replacement of both the CPU and all SM modules, plus reprogramming in TIA Portal (STEP 7 Micro/WIN programs are not directly portable). For sites where a full migration is not feasible, the S7-200 SMART (6ES7288-series) offers a partial functional equivalent with a similar instruction set but a different physical form factor and communication protocol stack.

S7-200 SM 222 Full Catalog & Functionalities (SKU List)

Digital Output Modules — Transistor (DC):

• 6ES7222-1BF22-0XA0: SM 222, 8 x 24 VDC transistor outputs, 0.75 A/point, source type
• 6ES7222-1BH22-0XA0: SM 222, 16 x 24 VDC transistor outputs, 0.75 A/point, source type
• 6ES7222-1EF22-0XA0: SM 222, 8 x 24 VDC transistor outputs, 0.75 A/point, sink type
• 6ES7222-1EH22-0XA0: SM 222, 16 x 24 VDC transistor outputs, 0.75 A/point, sink type

Digital Output Modules — Relay Contact:

• 6ES7222-1HF22-0XA0: SM 222, 8 x relay outputs, 2 A/point, 24 VDC or 250 VAC, NO contacts
• 6ES7222-1HH22-0XA0: SM 222, 16 x relay outputs, 2 A/point, 24 VDC or 250 VAC, NO contacts

Combined Digital I/O Modules (SM 223):

• 6ES7223-1BF22-0XA0: SM 223, 4 DI / 4 DO transistor, 24 VDC
• 6ES7223-1BH22-0XA0: SM 223, 8 DI / 8 DO transistor, 24 VDC
• 6ES7223-1PF22-0XA0: SM 223, 4 DI / 4 DO relay, 24 VDC / 250 VAC
• 6ES7223-1PH22-0XA0: SM 223, 8 DI / 8 DO relay, 24 VDC / 250 VAC

Digital Input Modules (SM 221):

• 6ES7221-1BF22-0XA0: SM 221, 8 x 24 VDC digital inputs, sink/source
• 6ES7221-1BH22-0XA0: SM 221, 16 x 24 VDC digital inputs, sink/source
• 6ES7221-1EF22-0XA0: SM 221, 8 x 120/230 VAC digital inputs

Analog Modules (SM 231 / SM 232 / SM 235):

• 6ES7231-0HC22-0XA0: SM 231, 4 x analog inputs, 12-bit resolution, ±10 V / 0–20 mA
• 6ES7232-0HB22-0XA0: SM 232, 2 x analog outputs, 12-bit resolution, ±10 V / 0–20 mA
• 6ES7235-0KD22-0XA0: SM 235, 4 AI / 1 AO combined analog module

Quality Control for the S7-200 SM 222 Range

The SM 222 relay output modules present specific test requirements due to their electromechanical relay contacts and shared expansion bus interface. DriveKNMS applies the following verification protocol to all S7-200 SM 222 units: (1) Visual inspection of relay contact surfaces, PCB traces, and the 34-pin expansion connector for oxidation, mechanical damage, or counterfeit markings. (2) Functional relay actuation test: each output point is cycled under a resistive load at rated voltage (24 VDC and 230 VAC) to verify contact closure resistance below 100 mΩ and release time within specification. (3) Expansion bus communication test: the module is connected to a reference S7-200 CPU (6ES7214-series) and polled via STEP 7 Micro/WIN to confirm correct module identification, I/O mapping, and error-free data exchange. (4) Isolation test: 500 VDC hipot applied between relay coil circuit and contact circuit to verify dielectric integrity. Units failing any stage are quarantined and not listed for sale.