Adding serial ports to a 10 inch IP66 touchscreen

Short answer: keep the touchscreen you like and add the ports at the enclosure. Buy a 10.1 in panel PC for its screen, brightness and IP66 front bezel, then bring the two extra serial lines out through two IP67 M12 panel jacks in factory cutouts 2 in [50 mm] below the display opening. The bezel keeps its rating, the door keeps its gasket, and both new ports land where a hose cannot pool water on them. If the panel PC comes up short on COM ports, a two-port Ethernet-to-serial module behind the display adds both for about 2 W.

Which touchscreen do you buy when the port count is wrong?

Buy the 10.1 in unit you want for its screen, brightness and bezel rating, and stop rejecting candidates over COM ports: one COM plus a two-port device server already gives you baseline plus two serial ports for about 2 W. The trap is treating port count as a touchscreen criterion. Most 10 inch industrial panels ship with one or two COM ports; the four-port units are a short list, and it shrinks again once you add an IP66 bezel and a 1000 nit face for a washdown line. Split the problem instead: pick the display for the thing you stare at all shift, and create the ports at the enclosure.

Two routes, and both end at the same two jacks on the door. Route A: order a panel PC with three physical COM ports — your baseline plus two — and pass them out. Route B: order any panel PC with one COM and hang a two-port Ethernet-to-serial device server on the bracket behind the display; its ports arrive as COM3 and COM4 and cost you one Ethernet socket. Route B keeps your shortlist wide open, which is the whole point.

Before you commit to the display, read up on what an HMI's IP66 bezel rating actually covers in outdoor washdown — that front-of-glass number is the one your spec enforces. For the glass, seal and mounting side of the choice, the washdown touchscreen build goes deeper.

How many ports and how much power?

Worked example, with the arithmetic. The line today talks to one drive over RS-232, so your baseline is 1 port and the target is 1 + 2 = 3. The panel PC you like carries 1 COM, so a two-port device server closes the gap: 1 + 2 = 3. It draws about 2 W at 24 V DC, which is 2 W ÷ 24 V = 0.08 A on your control supply, and it warms a slim sealed shell by roughly 3 C [5 F] — small next to the 25 to 30 W the panel PC itself gives off.

Where do the two serial cutouts go?

Two 16.2 mm [0.64 in] round holes in the door, at least 2 in [50 mm] below the display opening and 1 in [25 mm] apart between their edges, so a nut driver reaches both and the bezel gasket keeps its full land. Below the display does two jobs at once: the mating faces sit out of the sheet of water that runs down the door during a washdown, and your knuckles get room when you plug in a cord. Keep every hole at least 0.5 in [13 mm] from a bend or a weld seam, because the O-ring seals against flat, undistorted metal.

Lay the whole face out in the cutout designer: it places the display opening and both serial holes, checks the spacing against the gasket and the bends, and exports one drawing that goes straight to the shop. The display-opening method is the same one the 7 inch custom touchscreen build walks through, and the cutouts, glands and HMI windows guide carries the spacing rules for everything else you will put on that door.

If you would rather land D-Subs on the door, a DB9 needs a 1.2 x 0.4 in [31 x 10 mm] opening with flange screws on 1 in [25 mm] centers, plus a molded flange gasket — environmental sealing between a connector flange and its panel is exactly what those D-Sub gaskets are built for. The round M12 route does the same job with one O-ring and one wrench, which is why it wins on a hose-down door.

Which sealed connector carries a serial line?

An 8-pin M12 A-coded jack carries one RS-232 line with full handshake, and the same shell carries RS-485 with pins to spare; mated, the pair is IP67. The pin count follows the signals:

Distance picks the interface before the connector does. RS-232 holds together to about 15 m [50 ft]; past that, move to RS-485, which runs 1200 m [4000 ft] at up to 100 kbit/s. Your barcode scanner at 8 m stays RS-232 (8 < 15); the weigh-scale at 60 m goes RS-485 (60 > 15, and far under 1200).

Two other sealed ways out exist. A sealed RJ45 bulkhead coupler handles serial that rides a Cat5 extender, and the RJ45 gland and connector sizing page covers that route. For a pre-terminated cord, a nylon M12 cable gland rated IP68 by its maker seals cable from 4.5 to 7.8 mm [0.18 to 0.31 in] OD on a 12 mm thread with 9 mm of thread length. Sealed panel-mount connector options compare the families side by side.

What holds the IP66 rating with two extra holes?

The rating holds when every part in the wet path carries at least IP66 — the bezel seal, the door gasket, and both jack flanges at IP67 — and the holes are factory cut with a flat, burr-free seat. An enclosure is as tight as its lowest-rated part, and each hole adds three of them: the jack body, its flange O-ring, and whatever is mated in the field. Mated and locked, a good M12 pair is IP67, tested harder than IP66: IEC 60529 proves the digit 6 with a 12.5 mm nozzle delivering 100 L/min from 2.5 to 3 m for at least 3 min, and the digit 7 with 1 m [3.3 ft] of immersion for 30 min.

Say the ratings plainly, because your inspector will. The display's IP66 bezel, the jacks' IP67 and our shells are all manufacturer ratings; our enclosures are not UL listed, and NEMA does not test or certify enclosures. The IP66 your spec asks for lives on the display bezel — the touchscreen itself — and our HMI housings hold it with an IP65-type front seal with the display installed, manufacturer rated, while our wall-mount boxes are rated NEMA 4X / IP66 by the manufacturer; not UL listed.

Factory cutouts are part of that chain. A laser-cut 16.2 mm hole arrives round, flat and deburred, so the O-ring seats on uninterrupted metal; a hand-drilled one drags a burr under the seal. Whether drilling a housing affects its rating works through the evidence — the short version: holes from the factory, hardware from you, rating intact.

How do you fit the two connectors, step by step?

Half a day covers it: lay out two 16.2 mm holes, have them laser cut with the display opening, seat two O-ringed jacks, wire them to the server inside, and prove comms before the first washdown.

1. Count and choose: baseline 1 port, target 1 + 2 = 3; any line past 15 m [50 ft] becomes RS-485.
2. Order parts: 2 × M12 A-coded 8-pin panel jacks rated IP67 mated, 2 flange O-rings, 2 IP67 caps, and the two-port Ethernet-to-serial server if the PC is short a UART.
3. Lay out the face in the cutout designer: display opening to the bezel drawing, then both 16.2 mm holes, 2 in [50 mm] below it, 1 in [25 mm] apart, 0.5 in [13 mm] from the bends; send the layout and approve the drawing we send back.
4. When the housing lands, mount the display first: bezel gasket even in its channel all the way round, latches closed.
5. Seat each jack from the front, O-ring flat against its seat, and run the locknut down from behind until the ring compresses evenly — snug, then a look all round.
6. Wire inside: server port 1 to jack 1, port 2 to jack 2, following the jack drawing; label D+, D− and GND at both ends.
7. Feed the server 24 V DC (0.08 A for the 2 W unit) and give it its Ethernet line to the panel PC.
8. Cap both jacks with their IP67 caps until the field cords arrive.

How do you check the seal and the comms when it is done?

Prove three things in this order: comms on both ports over the full cable run, visible O-ring compression all round each jack, and a dry interior after 3 min of spray at the door from about 3 m. Run comms first, doors shut and line live: talk to the scale at 9.6 kbaud over the full 60 m and count framing errors for an hour; the scanner at 8 m should hold 115.2 kbaud without a lost byte.

Then the water. Lock out and prove de-energized before you open anything, spray the door for 3 min from about 3 m — the IP66 condition — and open the rear cover over a dry rag. Water at a jack flange means the O-ring sat on a burr or the nut stopped shy of even compression; a dry interior closes the job. Re-close the cover with its gasket clean.

What mistakes drop the rating?

Five slip-ups cost the seal, and all five surface at commissioning: a hand-drilled hole under an O-ring, a missing flange gasket, an open unused jack, a cord too thin for its gland, and a bare DB9 through the door. The fixes are cheap:

• Have the 16.2 mm holes cut in the same factory pass as the display opening; burrs from a hand drill lift an O-ring into a spiral leak path.
• Fit the O-ring or gasket shipped with every jack; metal-to-metal flanges leak at the first hose-down.
• Cap any jack waiting for its cord — an open 8-pin M12 is a straight shot into the panel.
• Match cord to gland: sealing starts at 4.5 mm [0.18 in] OD, and a 4 mm cord leaves the seal slack.
• Keep D-Subs inside the shell and take the serial out through M12; a through-door DB9 depends on a molded flange gasket that washdown finds quickly.

What goes on the order for a 10 inch touchscreen with two extra serial ports?

Order the 10.1 in 304 stainless HMI housing cut for your panel PC, with the display opening and both 16.2 mm serial holes on the same drawing, and it is delivered in 10 business days from your approval of that drawing. Write the order like this:

Every display size from 7 to 23.8 in sits in the HMI housing category, cut the same way. A salt-air or chlorine site moves you to 316L, which custom enclosures cover from one piece on the same cutout drawing — also delivered in 10 business days, counted from your approval. Order that list and the two serial ports stop being a touchscreen problem: the display earns its IP66 on the front, and the ports land on two round IP67 faces below it.

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