Siemens 6ES7223-1PL32-0XB0 — S7-1200 Relay Module Buying Guide

By Abdullah Zahid
12 min read
Siemens 6ES7223-1PL32-0XB0 SM 1223 digital I/O relay module for S7-1200 PLC DIN rail installation

Siemens 6ES7223-1PL32-0XB0 — SIMATIC S7-1200 Digital I/O SM 1223, 16 DI/16 DO, 16 DI 24 V DC Sink/Source, 16 DO Relay 2 A: Specifications, Wiring, and Selection Guide

If you are specifying a relay output expansion module for an S7-1200 system and the field devices include solenoid valves, contactors, or AC-switched loads, the Siemens 6ES7223-1PL32-0XB0 is the module most engineers reach for first. It delivers 16 sink/source digital inputs at 24 V DC and 16 relay outputs rated at 2 A with switching capability from 5 V DC up to 250 V AC — all within a single signal module slot on the S7-1200 base unit. The relay outputs provide galvanic isolation per output to the backplane, making it the correct choice when inductive load isolation is a firm requirement rather than an afterthought.

If you have already confirmed this is the right part, check current pricing and availability at LeadTime.ca — ships worldwide.

Who Should Buy the 6ES7223-1PL32-0XB0 — and Who Shouldn't

This module is the correct choice when all of the following apply to your project:

  • Your base controller is an S7-1200 CPU with at least one available signal module slot
  • You require exactly 16 digital inputs at 24 V DC (sink/source) and 16 relay outputs in a single module
  • Your output loads are inductive or AC-rated — solenoid valves, contactor coils, or AC indicator loads up to 250 V AC
  • The installation environment operates between -20°C and 60°C horizontal, with an IP20-rated enclosure acceptable
  • Your relay outputs will operate within the 2 A switching capacity at rated voltage

If your application requires transistor outputs for fast DC switching at 0.5 A, the correct alternative is the 6ES7223-1BL32-0XB0. If your base unit is an S7-1500 or S7-300, this module is not compatible — the signal module slot architecture is unique to the S7-1200 family.

On this page:

What the 6ES7223-1PL32-0XB0 Actually Does in an S7-1200 System

The 6ES7223-1PL32-0XB0 is a digital input/output expansion module in the SIMATIC S7-1200 SM 1223 family. It slides into a signal module slot on the S7-1200 base unit and draws its 5 V and 24 V power directly from the backplane — no separate power wiring to the module itself. The 16 digital inputs accept 24 V DC signals from field sensors, limit switches, or proximity detectors in either sink or source configuration. Each input group of two channels is galvanically isolated, which reduces cross-talk between sensor circuits operating at different common potentials.

The 16 relay outputs are each galvanically isolated to the backplane individually, which is the key distinction from transistor output modules. Each relay contact can switch loads from 5 V DC to 30 V DC or 5 V AC to 250 V AC, carrying up to 2 A at rated voltage. The mechanical relay contacts are rated for 10 million cycles without electrical load and 100,000 cycles at rated load — numbers that reflect typical industrial duty cycles over several years of operation. When your application involves switching 115 V AC or 230 V AC solenoid coils, indicator lamps rated at 200 W AC, or inductive contactors with coil voltages anywhere in the 5 V to 250 V AC range, this is the module that handles those requirements directly without external relay cards in between.

The input delay is configurable in TIA Portal from 0.2 ms to 12.8 ms, giving engineers direct control over noise filtering versus response speed. The backplane draw is 180 mA maximum at 5 V DC, which must be accounted for in the total S7-1200 CPU backplane load budget alongside any other signal modules installed.

Typical System Architecture for the SM 1223 Relay Module

The 6ES7223-1PL32-0XB0 sits between the S7-1200 CPU and the field devices, functioning as the physical interface layer that translates backplane bus signals into relay contact closures and reports field sensor states back to the CPU. Here is where it fits in a typical installation:

  • Regulated 24 V DC power supply feeds the S7-1200 base unit, which distributes backplane power to all installed signal modules including this one
  • S7-1200 CPU (e.g., CPU 1214C or CPU 1215C) occupies the leftmost position and communicates with the 6ES7223-1PL32-0XB0 via the internal backplane bus
  • The 6ES7223-1PL32-0XB0 occupies one signal module slot to the right of the CPU, receiving input data from field sensors wired to the 16 DI terminals
  • Relay output terminals on the module connect directly to solenoid coil circuits, contactor coils, or AC indicator loads — the relay contacts carry the actual field switching current
  • External 24 V DC supply for field devices (sensors and DC solenoids) is separate from the backplane supply and wired directly to the sensor commons and relay load circuits

Where Engineers Deploy This Module: Industries and Use Cases

In packaging machinery, the 6ES7223-1PL32-0XB0 is a standard build component for multi-function control panels where solenoid-actuated product routing, reject gates, and conveyor contactors must all be driven from a single S7-1200 rack. The relay outputs eliminate the need for intermediate relay cards on those output circuits.

Food and beverage processing lines frequently use this module where 115 V AC or 230 V AC solenoid valves control CIP (clean-in-place) circuits, filling heads, and divert valves. The ability to switch up to 250 V AC directly through the relay contacts matches the coil voltage ratings found in most industrial solenoid valves used in those environments.

Machine builders performing legacy retrofits — replacing failed or obsolete PLCs with S7-1200 CPUs — use this module to replicate the original I/O count without over-specifying the new controller. A single 6ES7223-1PL32-0XB0 covers 16 inputs and 16 outputs in 70 mm of panel width.

Material handling and automotive assembly applications use this module for contactor control where conveyor drive starters, lift actuators, and pneumatic cylinders are switched at low control voltages while the relay contacts provide the required separation between the 24 V DC control circuit and higher-voltage motor starter coils.

Application Typical Deployment
Packaging machinery Solenoid-actuated reject gates and conveyor routing; relay outputs replace intermediate relay cards
Food and beverage processing 115 V AC / 230 V AC solenoid valve switching for CIP and filling lines
Legacy machine retrofit Replacing failed PLCs with S7-1200; 16 DI/16 DO in one slot matches original I/O layout
Automotive assembly Contactor coil switching for conveyor drives and pneumatic cylinder control
Building automation and HVAC Relay switching of AC fan contactors, valve actuators, and indicator lamps up to 200 W AC
Water treatment Pump contactor and solenoid dosing valve control with galvanic-isolated input monitoring

Purchase-Decision Specs: What You Need to Know Before Ordering

Parameter Value
Number of digital inputs 16, sink/source, 24 V DC (rated range 20.4–28.8 V DC)
Number of relay outputs 16, mechanical relay contacts, 2 A switching capacity at rated voltage
Output switching voltage range 5–30 V DC or 5–250 V AC
Lamp load capacity 30 W DC / 200 W AC
Electrical relay cycle rating 100,000 cycles at rated load voltage
Mechanical relay cycle rating 10 million cycles (no electrical load)
Input delay (configurable) 0.2 ms to 12.8 ms via TIA Portal
Operating temperature -20°C to 60°C horizontal; -20°C to 50°C vertical
Dimensions (W x H x D) 70 mm x 100 mm x 75 mm
Certifications CE, CSA, UL (UL 508), cULus, FM, RCM

Full technical specifications are available on the product page at LeadTime.ca.

6ES7223-1PL32-0XB0 vs. 6ES7223-1BL32-0XB0: Relay or Transistor?

The most common selection error engineers make at this stage is ordering the relay variant when transistor outputs would reduce maintenance overhead, or vice versa. The table below covers the decisive differences.

Feature 6ES7223-1PL32-0XB0 (Relay) 6ES7223-1BL32-0XB0 (Transistor)
Output type Mechanical relay contact Solid-state transistor
Switching capacity 2 A at rated voltage 0.5 A
AC load switching Yes, 5–250 V AC No — DC only
Inductive load handling Direct (with snubber/diode recommended) Limited — requires external protection
Mechanical wear Yes — 100,000 cycles at rated load None
Response speed Under 50 ms typical Faster (solid state)
Typical application fit Solenoids, contactors, AC loads, indicator lamps DC sensors, PLC inputs, fast-switching DC circuits

If your architecture requires AC solenoid switching or inductive contactor coils, the 6ES7223-1PL32-0XB0 is the correct choice — check current availability at LeadTime.ca.

Expert Verdict: Honest Assessment for Automation Engineers

The 6ES7223-1PL32-0XB0 earns its place as a standard module in S7-1200 builds specifically because relay outputs eliminate the engineering work of sizing and wiring intermediate relay cards for inductive and AC loads. The 2 A switching capacity covers the majority of solenoid coil and contactor coil applications in one terminal connection. The galvanic isolation per output to the backplane is a genuine engineering benefit — not marketing language — because it limits the blast radius of a wiring fault to a single output circuit rather than propagating across a common bus. The 70 mm panel footprint is compact enough that two of these modules add 32 inputs and 32 relay outputs to a base unit without exceeding the rail space of a medium-sized control panel.

The honest limitations: mechanical relay contacts have a finite electrical cycle life of 100,000 operations at rated load. For applications with relay activation frequencies above a few hundred cycles per hour, the transistor variant 6ES7223-1BL32-0XB0 will have lower lifetime maintenance cost. The IP20 enclosure rating also means this module is not suitable for wash-down environments or installations where dust ingress must be zero — if your panel lacks its own sealed enclosure, this becomes a maintenance planning factor. At temperatures above 50°C horizontal, the simultaneous output limit drops to 8 — a thermal constraint that affects dense multi-output applications in warm enclosures. Plan your cooling before finalizing the mounting orientation and output duty cycle.

From a procurement standpoint, standard lead times from authorized distributors run 2 to 4 weeks for in-stock European suppliers and 4 to 6 weeks for North American fulfillment depending on local stock levels. For production runs requiring 5 or more units, volume pricing from authorized distributors typically delivers 10% or more off single-unit price. If your project timeline is tight, order 6 to 8 weeks ahead. If this matches your system requirements, view current stock and pricing at LeadTime.ca.

For volume pricing or to confirm lead time before committing to a build, contact the LeadTime.ca team directly — we ship worldwide.

Wiring and Installation Overview

  • Slide the module into the next available signal module slot on the S7-1200 base unit until the retaining clips engage with an audible click — the module receives 5 V and 24 V power automatically from the backplane; no external power wiring to the module is required
  • Connect the front terminal connector with field device wiring: digital inputs use 24 V DC positive (L+) and sensor common to each 2-channel input group; both PNP (source) and NPN (sink) sensors are supported
  • For relay output wiring, connect the load supply voltage (5–30 V DC or 5–250 V AC) and the load return to each relay terminal pair — each relay output circuit is independently isolated to the backplane
  • Fit a diode or RC snubber on all inductive loads (solenoid coils, contactor coils) to suppress voltage spikes that would otherwise accelerate relay contact wear
  • In TIA Portal hardware configuration, explicitly add the 6ES7223-1PL32-0XB0 to the S7-1200 base unit and set input delay filters per channel group (1.6 ms recommended as a starting point for noisy industrial environments) before downloading to the CPU

What Engineers Get Wrong When Ordering This Part

Before placing an order, run through the following checklist — these are the most common wrong-part scenarios that result in returns or project delays:

  1. Confirm base PLC is S7-1200, not S7-1500, S7-300, or S7-400 (different slot formats)
  2. Verify you need 16 inputs AND 16 outputs (not 8+8 or other ratios)
  3. Confirm relay output requirement (not transistor, not analog)
  4. Check that field devices are 24 V DC inputs (not 48 V, not AC)
  5. Verify system voltage supply is 24 V DC, not 110 V AC or 230 V AC
  6. Ensure you have one free signal module slot on your S7-1200 CPU
  7. Confirm installation will not exceed -20 to 60°C horizontal operating range

If all seven checks pass, the 6ES7223-1PL32-0XB0 is available at LeadTime.ca — or contact the team if you need to verify compatibility for an unusual application.

Frequently Asked Questions

Can the 6ES7223-1PL32-0XB0 be used with an S7-1500 or S7-300 PLC?

No. This module is exclusive to the S7-1200 due to the unique signal module slot architecture of that platform. The S7-1500 uses different module form factors, and the S7-300 uses 21 mm wide profile modules. There is no cross-series compatibility.

What is the maximum current each relay output can switch?

2 A at rated voltage. Exceeding this will cause relay contact degradation or arc damage over time. For high-cycle applications, a current of 1 A is recommended for extended contact life. Always verify actual load current before wiring.

Can all 16 relay outputs be activated simultaneously at high ambient temperatures?

At or below 40°C horizontal, all 16 relay outputs can be activated simultaneously. At 50°C horizontal or above, the simultaneous activation limit drops to 8 outputs. At 60°C, 8 simultaneous outputs is the maximum and sustained operation at that limit accelerates contact wear. Vertical mounting reduces the thermal margin by approximately 10°C compared to horizontal installation.

Are the relay outputs suitable for switching 230 V AC solenoid valves?

Yes. The relay output voltage range supports 5 V AC to 250 V AC. A 230 V AC solenoid coil is within specification provided the coil current does not exceed 2 A. Verify actual coil inrush current in addition to steady-state current, and fit an RC snubber on the coil to protect the relay contact.

Is the input delay filter configurable, and what setting should I start with?

Yes, input delay is configurable in TIA Portal with options of 0.2 ms, 0.4 ms, 0.8 ms, 1.6 ms, 3.2 ms, 6.4 ms, or 12.8 ms. For most industrial environments with electrical noise from motor drives or switching circuits nearby, starting at 1.6 ms balances noise immunity with adequate response speed. Reduce to 0.2 ms only when fast input response is a hard requirement.

Does the 6ES7223-1PL32-0XB0 require a separate power supply?

The module itself draws power from the S7-1200 backplane — 180 mA maximum at 5 V DC — and requires no separate power wiring. However, the field devices connected to the digital inputs and the loads switched by the relay outputs require their own external power supplies. The backplane supply is not a source for field device power.

Price, Lead Time, and How to Order From Anywhere in the World

  • LeadTime.ca ships worldwide — the 6ES7223-1PL32-0XB0 is available to buyers outside North America as well as within Canada and the United States
  • Standard market lead times run 2 to 4 weeks from authorized stock; plan 6 to 8 weeks ahead for production volume orders to avoid project delays
  • Volume pricing is available for orders of 5 or more units — contact the team for a formal quote before committing to a build schedule
  • LeadTime.ca sources hard-to-find SIMATIC S7-1200 modules including SM 1223 variants; if standard channels show extended lead times, the team can advise on sourcing options

At-a-Glance Summary

  • Module: Siemens 6ES7223-1PL32-0XB0 — SIMATIC S7-1200 SM 1223, 16 DI / 16 DO relay
  • 16 digital inputs at 24 V DC (sink/source), rated range 20.4–28.8 V DC, input delay 0.2–12.8 ms configurable
  • 16 relay outputs rated 2 A at rated voltage; switching range 5–30 V DC or 5–250 V AC
  • Lamp load capacity: 30 W DC / 200 W AC; mechanical relay life: 10 million cycles; electrical relay life: 100,000 cycles at rated load
  • Galvanic isolation: per 2-input group for inputs; per individual output to backplane for relay outputs
  • Backplane draw: 180 mA maximum at 5 V DC; no external power supply required for the module
  • Dimensions: 70 mm x 100 mm x 75 mm; weight approximately 350 g; IP20; DIN rail mount
  • Operating temperature: -20°C to 60°C horizontal; simultaneous output limit drops to 8 above 50°C horizontal
  • Certifications: CE, CSA, UL (UL 508), cULus, FM, RCM
  • Correct alternative for transistor DC outputs: 6ES7223-1BL32-0XB0 (0.5 A, DC only)
  • Active product; typical lead time 2–4 weeks; plan 6–8 weeks for volume production orders