PLC Expansion Modules: When the Base CPU Is Enough and When You Add More I/O
Customers come to us for expansion modules in two scenarios. First, at design stage the engineer has tallied the I/O count and orders CPU plus the required SM/AI/AO together. Second, an old line that has run 5-10 years and the customer adds, say, one more temperature sensor or valve while the base CPU has no free points. In the second case the controller series must be stated exactly, because modules do not cross between brands or even between generations of the same brand (FX2N-4AD will not seat on an FX5U).
We split modules by signal type. Discrete DI/DO: buttons, limit switches, relays; 24 V on/off signals. Analogue AI/AO: proportional 4-20 mA or 0-10 V; temperature, pressure, frequency, controlling a valve or VFD via 0-10 V. Special: RTD/PT100/thermocouples, high-speed counting, positioning. Communication: RS-485, Ethernet, CANopen for distributed systems. Before shipping we ask for the exact CPU model and series, to avoid sending a module that physically will not seat on the rack.
Which Modules We Pick for Siemens, Mitsubishi, Delta, Schneider
By our sales the top-5 looks like this. Delta DVP16SP11T: 8DI plus 8DO transistor, DVP-S series, a steady bestseller for packaging lines. Siemens SM 1232 AQ4: 4 analogue outputs, 14-bit, for S7-1200; valve and regulator control. Mitsubishi FX3U-4DA: 4AO for FX3U, dosing. Siemens covers 99 modules (S7-1200, S7-300, LOGO 8), Mitsubishi 96 (FX2N/FX3U/FX3G/FX1N plus L), Delta 89 (DVP-S/ES2/EX2/EH2), Schneider 40 (TWIDO plus SR3 Zelio). Comparison of the most requested:
| Module | Type | Inputs/Outputs | PLC Series | Application |
|---|---|---|---|---|
| Delta DVP16SP11T | Discrete DI/DO | 8DI + 8DO (transistor) | DVP-S | Conveyors, packaging lines |
| Siemens SM 1231 AI8 | Analog AI | 8AI (13-bit) | S7-1200 | Temperature and pressure monitoring |
| Siemens SM 1232 AQ4 | Analog AO | 4AO (14-bit) | S7-1200 | Valve and regulator control |
| Delta DVP06XA-E2 | Analog AI/AO | 4AI + 4AO | DVP-ES2/EX2 | Process control, HVAC |
| Mitsubishi FX2N-4AD | Analog AI | 4AI (12-bit) | FX2N | Weighing, batching |
PLC Expansion Module Manufacturers
Our catalog includes modules from leading industrial automation manufacturers with proven sales in Ukraine:
- Siemens — 99 modules across S7-1200 (SM 1221/1222/1223/1231/1232), S7-300 (SM 321/322/331/332), and LOGO 8 series. The standard for large industrial facilities.
- Mitsubishi Electric — 96 modules across FX2N, FX3U, FX3G, FX1N, and L-series. Reliable solutions for machine tools and packaging equipment.
- Delta Electronics — 89 modules across DVP-S, DVP-ES2/EX2, and DVP-EH2 series. Optimal price-to-performance ratio for serial machines.
- Schneider Electric — 40 modules across TWIDO and SR3 (Zelio Logic) series. Compact solutions for building automation and HVAC.
Expansion Modules by Specifications
Select a module by signal type and channel count. Discrete modules range from 6 to 32 I/O points with relay or transistor outputs. Analog modules offer 12-bit to 16-bit resolution with 4-20 mA, 0-10V, PT100, and J/K/T thermocouple inputs. Communication modules with RS-485, Ethernet, and CANopen interfaces enable distributed control system architectures.
Warranty and Support
All PLC expansion modules come with an official manufacturer warranty of 12 to 24 months. Delivery across Ukraine via Nova Poshta and Ukrposhta. Payment options: bank transfer for businesses, card payment or cash on delivery for individuals. Free technical consultation on module selection and I/O system design.
