SIMATIC HMI KP400 Comfort 4.3-inch Key Panel, PROFINET and MPI/PROFIBUS DP (6AV2124-1DC01-0AX0) CAN Electric — Industrial Automation Parts Supplier

A screen and a keypad for when glass is the wrong answer

Not every station needs a touch surface. In a cell where the operator wears thick gloves, holds a tool, or works a panel that gets splashed, hit or simply used thousands of times a shift, a membrane keypad with lit buttons is the more honest design. The KP400 gives you a readable message screen plus eight assignable keys whose LEDs can show machine state — a status lamp and a button in one place. Where a touch panel would demand a clean finger and an intact front, this one keeps working through the conditions a real floor produces.

Who still specifies it, and who should stop

Three buyers have a reason for this order number: replacing a failed unit whose housing, cutout and TIA device already match, so the machine restarts without mechanical rework; keeping a spare for a plant that runs several, because a stopped line costs more than a small panel on a shelf; and shipping a like-for-like unit with an existing machine order. What it is not is a graphics panel — 480 × 272 is enough for text, status and buttons, not for dense visualization, and that is by design.

For a new project the straight answer is the MTP400 below; for a 4-inch device that also wants a touch layer, the KTP400 Comfort (2DC01) is the same housing with a resistive screen added. The KP400 is the choice when you deliberately do not want a touch.

Data per the Siemens product documentation and Industry Mall entry. The cutout, front dimensions and depth are from the mounting instructions — cut the enclosure only after the current data sheet is checked, because plate thickness and flatness decide whether the front seal actually seals.

Buttons you can find without looking, and prove with a press

A lit function key is a status indicator and an actuator in one component. Operators learn the position of the eight keys by feel, so a glance-and-press works in low light or behind a guard, and a key that clicks is a confirmed action in a way a soft target on glass is not. For acknowledge, start, stop or mode-select functions that get hit every cycle, a physical key reduces error and dispute.

Input and output without a remote I/O drop

The eight direct keys map straight to S7 input bits and the eight DP direct LEDs to S7 output bits, so a button or a lamp on the panel becomes controller I/O without wiring a separate station. On a compact machine this removes a box, a cable and a commissioning step — the panel is the I/O point.

Survival where a touch front fails

There is no glass to crack, no surface that smears or shatters, and nothing that floods when a hose passes too close from the front face. The trade is density: a key panel does not show a video or a full schematic, and at 0.857 kg and 3.1 W it asks little behind the cutout — which is why it fits doors, pendant arms and panels where a 12-inch device would never go. Match the device to the job: keys for control points and messages, a touch or larger panel for visualization.

The two share the housing, so the cutout is the same — but project device types differ, and a KTP400 archive will not download unchanged onto a KP400. Choose the key-only device when the screen is a read-out and the keys do the work; choose the KTP400 when operators also need to tap through screens.

Same-model swap: keep the cutout, restore the project

Four things decide whether the machine restarts on the same shift: cutout, depth behind the door, 24 V supply, and the project. With a known-good project on an SD card, a replacement needs no laptop at the machine — insert the card and load. Without one, an engineering seat has to open, recompile and download, so put that resource next to the electrician.

Moving on: no 4-inch Unified Comfort successor exists

Unlike the 7-inch to 22-inch Comfort sizes, each of which has a same-size MTP Unified Comfort successor, the 4-inch Comfort has none — the Unified Comfort range begins at 7 inches with the MTP700 (6AV2128-3GB06-0AX1). For a 4-inch footprint the realistic routes are to step up to that 7-inch MTP700 if the cutout allows, or to use the 4-inch MTP400 Unified Basic (6AV2123-3DB32-0AW0) on the WinCC Unified platform — a Basic-class panel, not Comfort. None of these carry physical keys, so a station that depended on the eight buttons regains them via the KP8 (eight-button) or KP32 (thirty-two-button) key module on PROFINET.

What else changes when you cross that line

The platform moves from Windows CE 6.0 to the Linux-based Unified system, the engineering tool moves from WinCC Comfort V11 to WinCC Unified Comfort, and the device type in the project changes. Screens do not port one to one, so the upgrade is a project with a schedule, not a download. Treat the keypad decision as part of the migration plan, not an afterthought.

The 4-inch Comfort has no same-size Unified Comfort successor; the MTP700 (6AV2128-3GB06-0AX1) is the smallest Unified Comfort and is a 7-inch upsize, while the 4-inch MTP400 Unified Basic (6AV2123-3DB32-0AW0) is a Basic-class device. The KP8/KP32 key modules restore physical keys on any touch successor. Confirm the chosen route and key-module fit against the current Siemens catalogue before ordering — the panel and the key module are separate order numbers.

The panel couples to SIMATIC S7-1200, S7-1500 and S7-300/400 over PROFINET or MPI/PROFIBUS DP, with Modbus TCP/IP and EtherNet/IP for third-party controllers. The single PROFINET port has no integrated switch, so a line topology needs an external switch — worth noting when the network drawing assumes one. The 19-inch TP1900 Comfort is the large touch end of the same standard family, the 7-inch KP700 Comfort is the next key panel up, and the TP1500 Comfort PRO range is the one whose rear is also sealed for washdown or outdoor cells.

How to order

• Email sales@can-electric.com with the order number, quantity, delivery country, and whether you are replacing a unit or stocking spares.
• State the condition you need — new, new-surplus or refurbished is written on the quote, not implied. For a running machine, send the hardware details from the old nameplate.
• The type is in phase-out, so availability comes from channel stock and is confirmed per order; prices are USD and ship from Hong Kong by DHL.