Panel builders sit in a different position from a single-industry plant — the same MCC or machine control panel they build this month might ship to a steel mill, a water utility, or a packaging line next month. That means a panel builder's bill of materials needs to be standardized, stockable, and flexible rather than tuned to one process. This page lists the Siemens PLCs, VFDs, HMI panels, and power supplies that panel manufacturers globally standardize on.
Applications in Panel Builder
- Motor control center (MCC) panels — multi-feeder starter/drive panels for pumps, fans, and conveyors across a plant.
- OEM machine control panels — dedicated control panels shipped with a specific machine, wired and tested before delivery to the end customer.
- Pump & compressor skid panels — compact panels mounted directly on or near a skid, handling local control and communication back to a plant DCS/SCADA.
- HVAC & boiler control panels — sequencing and interlock panels for building or utility HVAC and boiler plant.
- Custom process panels for any sector — one-off or low-volume panels engineered to a customer's process spec across food, chemical, textile, or any other vertical.
- Controller: a SIMATIC S7-1200 G2 or S7-1200 forms the core of most standard panels; simple single-function panels use the lower-cost S7-200 SMART.
- Distributed I/O: where field devices are spread across a large skid or machine, ET 200SP or the older ET 200S distributed I/O nodes reduce long individual cable runs back to the main panel.
- Drives: SINAMICS G120X for main motor loads, SINAMICS V20 for smaller auxiliary motors, and SINAMICS MM420 stocked for replacement on older installed panels.
- Operator interface: KTP700 for compact panel doors, KTP1200 as the standard machine-level panel, and TP1200 Comfort where the customer needs trending or multi-page navigation.
- Power & wiring: a SITOP power supply sized to the panel's total 24V DC load, sitting in every panel regardless of end industry.
- Engineering: TIA Portal programs the PLC, HMI, and drives in one project, and reusable code/faceplate libraries built in TIA Portal are what let a panel builder turn around a new panel quickly instead of starting from scratch each time.
Which Products Are Used in Panel Builder?
Below is the complete list of Siemens automation products commonly used in Panel Builder — PLC controllers, VFD drives, HMI panels, SCADA software and panel accessories. Click any product for MLFB numbers and pricing.
| Type | Product | MLFB / Model | Typical Use in Industry |
|---|---|---|---|
| PLC | Siemens SIMATIC S7-1200 G2 PLC | 6ES7212-1AG50 / 6ES7214-1AH50 / 6ES7215-1AG40 | Compact machine & skid control |
| PLC | Siemens SIMATIC S7-1200 PLC | 6ES7214-1AG40-0XB0 | Basic machine automation |
| PLC | Siemens SIMATIC S7-200 SMART PLC | 6ES7288-1SR20-0AA0 | Small standalone machines |
| PLC | Siemens ET 200SP Distributed I/O | 6ES7155-6AU01-0BN0 | Remote I/O & skid panels |
| PLC | Siemens ET 200S I/O System | 6ES7131-4BD01-0AA0 | Modular distributed I/O |
| VFD | Siemens SINAMICS G120X VFD | 6SL3200-0YC10 to 6SL3200-0YC28 | Pumps, fans, conveyors 0.75–15 kW |
| VFD | Siemens SINAMICS V20 VFD | 6SL3210-5BE21-1CV0 | Small motors, feeders, aux drives |
| VFD | Siemens SINAMICS MM420 VFD | 6SE9211-0DA40-1AA0 | Legacy motor speed control |
| HMI | Siemens HMI KTP700 Basic Panel | 6AV2123-2GB03-0AX0 | Compact operator panels |
| HMI | Siemens HMI KTP1200 Basic Panel | 6AV2124-0MC01-0AX0 | Machine-level HMI standard |
| HMI | Siemens HMI TP1200 Comfort Panel | 6AV2124-0GC01-0AX0 | Trending, recipes, larger displays |
| Software | Siemens TIA Portal (STEP 7 + WinCC) | 6ES7822 series | PLC + HMI + drive engineering |
| Power Supply | Siemens SITOP Power Supply | 6EP1333 series | 24V DC panel power |
PLC VFD HMI
Standard stock: S7-1200 G2 + KTP1200 + G120X + V20 + SITOP PSU, with TIA Portal for unified engineering.
Large distributed panel (multiple remote I/O clusters): add ET 200SP distributed I/O to the standard stack.
Why These Products in Panel Builder?
Panel builders benefit most from standardizing rather than optimizing per project — one engineering platform, TIA Portal, programs the PLC, configures the HMI, and parametrizes the VFDs, so the same code blocks and HMI faceplates get reused across projects instead of rebuilt each time. S7-1200 G2 is the default controller for most panels because its I/O count and pricing fit the majority of MCC and OEM machine panels; the compact S7-200 SMART covers smaller single-function panels where a full S7-1200 is more than needed.
When field devices are spread out across a large skid or machine rather than concentrated near the panel, ET 200SP (or the older ET 200S on legacy designs) lets wiring terminate at a nearby distributed I/O node over PROFINET/PROFIBUS instead of running every signal back to the main panel individually — this cuts both cable cost and commissioning time.
On drives, panel builders keep G120X and V20 as their default new-build stock, and hold MM420 mainly for replacement parts on panels already in the field. Every panel needs its own SITOP power supply sized to its total 24V DC load — this is one of the few components that doesn't vary by end industry, which is why it appears in nearly every panel bill of materials.
Common Mistakes to Avoid
- Mixing too many PLC/HMI families across projects: standardize on a small set (e.g. S7-1200 G2 + KTP1200) so spares stocking and staff training stay manageable.
- Undersizing the SITOP supply for future expansion: size the 24V DC power budget with headroom for I/O modules or a future HMI upgrade, not just the day-one load.
- Running long individual field cable back to the panel when distributed I/O would be cheaper: for skids or machines with spread-out sensors, evaluate ET 200SP against cable and labor cost before defaulting to direct wiring.
- Not documenting which drive family is fitted where: with G120X, V20, and MM420 potentially all in the field across different panels, keep a clear as-built record so future maintenance visits aren't guesswork.
Frequently Asked Questions
What do panel builders stock most?
S7-1200 G2 PLC, KTP1200 HMI, G120X and V20 VFD, SITOP 24V power supply, TIA Portal license.
Which PLC for small vs large MCC panel?
S7-200 SMART or S7-1200 G2 1212C for small. S7-1200 G2 1214C + ET 200SP for large distributed panels.
Which software for panel builder engineering?
TIA Portal — programs PLC, configures HMI and parametrizes VFD drives in one project.
Why do panel builders standardize on one PLC/HMI family instead of picking per project?
Standardizing on a small set of families (S7-1200 G2, KTP series, G120X/V20) lets a panel builder carry common spares, reuse tested code blocks and HMI faceplates across projects, and train panel wiring staff on one connector and terminal layout, which shortens both build time and commissioning.
When should a panel builder use ET 200SP distributed I/O instead of a local PLC I/O module?
ET 200SP is used when I/O points are physically spread across a skid or machine — field junction boxes, remote sensor clusters — so wiring runs back to a nearby distributed I/O node over PROFINET/PROFIBUS instead of long individual cable runs back to the main panel.
Does every panel need its own SITOP power supply?
Yes — PLCs, HMIs, and most I/O modules run on 24V DC, so a dedicated SITOP supply sized for the panel's total DC load (with headroom for future additions) is standard practice rather than sharing a supply across panels.
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