Short answer: wire a 22 mm momentary push button between the drive's spare digital input and its 24 V DC control terminal, set that input to fault acknowledge, and mount the operator through a factory-cut hole with a Type 4/4X rating. On a SINAMICS V20 compact drive, the Cn002 connection macro puts fault acknowledge on digital input DI3. Set the NPN or PNP link first. The button carries the wall's seal itself, so the box keeps its rating and you clear faults without opening the door. Below: the wiring, the parameter, the hole, and the heat check that says the door can stay shut.
Where the button lands on the drive
A remote fault reset is the simplest device you can add to a drive: a volt-free, normally open contact that the drive reads as one state change on one digital input. Pick a spare DI — on the SINAMICS V20 here, DI3 — and give it the fault-acknowledge function. Loading the Cn002 connection macro does that in one step, or you set the digital input's function directly in the parameter menu. One press acknowledges the latched fault. If the cause is still present the drive re-trips, which is the button telling you something else broke.
The input runs from the drive's control supply. Before wiring, set the drive's NPN or PNP connection: its wiring diagram prints the link terminals for each. That choice decides whether your second wire lands on the source terminal or the control common. A button with a plain normally open contact block works in either scheme, because it only closes the loop.
Two related cases sit nearby. If the button has to live on the machine frame rather than the enclosure door, its cable needs its own sealed entry; installing a cable gland without losing the rating covers that path. If the switch you must press is soldered on a board inside the box, actuating a PCB push button through a sealed enclosure wall and sealed PCB button enclosure design options cover the extension methods for that job.
What you need
22 mm is the industry-standard cutout for control buttons and indicators, which is why every control maker builds heads and contact blocks around it. Typical metal operator specifications of that size — the 800-TD008 data sheet is one — rate the heads Type 4 / 4X / 13, with a panel thickness range of 1.0 to 6.0 mm. That range drops to 4.0 mm once the standard anti-rotation washer goes on. Buy the head rated IP66 or Type 4X by its maker so the assembly holds the box's rating; what NEMA rating a panel keeps after you cut it and mount devices works through that weakest-part rule. For hole and sealing fundamentals, the enclosure cutouts, glands and windows guide carries the background.
| Part | Specification | Why it matters |
|---|---|---|
| Button head | 22 mm momentary, IP66 / Type 4X by its maker | the head carries the wall seal |
| Contact block | one normally open contact | one clean edge per press |
| Cutout | industry-standard size, factory cut | burr-free seat for the operator gasket |
| Door wall | within the 1.0–6.0 mm clamp range, 4.0 mm with washer | from the operator data sheet |
| Wire | two conductors, ferruled ends | DI3 plus the source or common terminal |
| Legend | marked FAULT RESET | so the next shift does not guess |
Mounting and wiring, step by step
- Lock out the supply and check for absence of voltage at the drive terminals before you land a single wire.
- Confirm DI3 is spare on the drive's I/O list, and write down its terminal number plus the source or common terminal your NPN/PNP link selects.
- Set the NPN or PNP link terminals exactly as the drive's wiring diagram prints them; changing them later means another power-down.
- Load the Cn002 connection macro, or set the digital input's function to fault acknowledge, and record the setting on the panel schedule.
- Lay the hole on the door clear of the gasket path and any display cut, and send it through the cutout designer so the box arrives with the hole already cut.
- Seat the operator gasket on the clean hole, fit the anti-rotation washer, and tighten the locknut to the torque the data sheet gives.
- Run the two wires from the contact block along the hinge side with slack for the door swing, and land them on DI3 and the source or common terminal.
- Restore power, wait for the next fault or induce a harmless one, and press: the fault code clears and the drive returns to ready.
Worked example: a SINAMICS V20 in a 12 x 10 x 6 in box
Inputs, each with its source:
- Enclosure: a 12 x 10 x 6 in 304 stainless wall-mount box from the catalog, manufacturer-rated NEMA 4X / IP66.
- Drive: a SINAMICS V20 with DI3 spare on its control side.
- Operator: an industry-standard head rated Type 4/4X/13, clamping panels 1.0 to 6.0 mm thick.
- Ambient 35 C and a 40 C target inside — the reference limit for drives and most electronics unless the datasheet allows more.
The rule in words: once the door stays latched, every watt the drive loses leaves through the stainless walls. Walls pass heat at k x A x dT watts, with k = 3.7 W/m²K for stainless.
The arithmetic:
- Convert the box: 12 x 10 x 6 in = 0.305 x 0.254 x 0.152 m.
- Surface: 2(0.305 x 0.254) + 2(0.305 x 0.152) + 2(0.254 x 0.152) = 0.155 + 0.093 + 0.077 = 0.325 m².
- Allowed rise: 40 - 35 = 5 K.
- Heat shed: 3.7 W/m²K x 0.325 m² x 5 K = 6.0 W.
The decision: take the drive's power-loss figure from its operating instructions and compare. At or under about 6 W, this box holds 40 C inside at 35 C ambient with the door latched, and the button adds nothing — its contact is volt-free. Above 6 W, order up a size: the 24 x 20 x 8 in box in the same family has 1.07 m² of surface. At the same ambient it sheds 3.7 W/m²K x 1.07 m² x 5 K = 19.8 W, more than three times the headroom, before you need a fan or a heat exchanger on a sealed wall.
Checks when the button is in
- Press during an active fault: the code clears and the drive shows ready. A press with no fault present does nothing.
- A meter on DI3 reads 24 V DC while the button is held and 0 V released, with the polarity your NPN/PNP link sets.
- The operator gasket sits evenly around the hole, the locknut is tight, and the legend reads FAULT RESET.
- The panel schedule inside the door lists the macro, the digital-input function and the link position, so the next reset finds them.
- The reset works with the door latched — that was the point of the job.
Mistakes that cost the reset or the rating
- An IP65 head caps an IP66 box at IP65 across the whole face. IEC 60529 tests second-digit 5 with a 6.3 mm nozzle at 12.5 L/min and digit 6 with a 12.5 mm nozzle at 100 L/min. A washdown hose sits in the second class, so buy the head rated IP66 / Type 4X.
- A ragged field-cut hole tears the operator gasket. Order the hole factory-cut; if you must cut in place, how to cut a hole in a stainless steel enclosure shows the tool sequence that keeps the seat flat.
- A wrong NPN/PNP link leaves the input stuck high or low, so the press never reaches the drive as an edge. Fix it at the link terminals rather than by swapping contact blocks.
- A normally closed block inverts the logic and acknowledges on release. Order the normally open block.
- Fault acknowledge is an operator convenience, never a safety function. With the automatic restart function set, the drive can start by itself after a supply interruption, so keep the lockout routine for any work inside the box.
What to order
Send the button layout through the designer with the rest of the panel: the hole position, the enclosure size your heat check picked, and the grade. Choose 304 for dry plants and 316L for washdown and coastal sites, both available as stainless wall-mount enclosures. The finished box is delivered in 10 business days, counted from your order, or from your approval of the drawing for custom work. Our enclosures are manufacturer-rated NEMA 4X / IP66 and not UL listed; pair yours with an operator its maker rates Type 4X, and the sealed wall keeps its promise.
Enclosures in this article
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 12 × 10 × 6 in | 304 stainless | 12 x 10 x 6 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
| 24 × 20 × 8 in | 304 stainless | 24 x 20 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Does adding a 22 mm push button through the wall lower the enclosure rating?
It does if the operator is rated below the box. A head marked Type 4 / 4X / 13 by its maker seals panels 1.0 to 6.0 mm thick and holds a NEMA 4X / IP66 box at full rating. A head marked IP65 only caps the whole face at IP65, because the finished assembly takes the rating of its lowest-rated part.
Can the drive clear its own faults without the button?
Sometimes. The SINAMICS V20 operating instructions note that settings such as the automatic restart function let the inverter restart on its own after an input power failure, which can include clearing a latched fault. That cuts both ways: the motor can spin with nobody at the button. Lock out before opening the door and treat the external button as the controlled acknowledge.
Will the fault-acknowledge setting survive a factory reset?
No. The drive's factory reset, P0970 = 1 in its manual, returns every parameter to the delivery state, so DI3 stops acknowledging until you reload the Cn002 macro or the digital-input function. Write the macro and the NPN/PNP link position on the panel schedule, and re-check both after anyone resets or swaps the drive.
Can one button reset two drives in the same enclosure?
Yes. Stack a second normally open contact block on the same 22 mm operator and land each block on its own drive's fault-acknowledge input — the press is shared, the inputs stay separate. Each drive needs its own macro or parameter setting, and two blocks fit a standard operator body without a second hole.
