Opta + screw terminals
Proves the machine works. Every unit is wired by hand: strip, ferrule, land and check each wire.
Per unit: every terminal, by hand
connector-boards --for "Arduino® Opta™"
From Opta prototype to production, without a custom controller PCB.
Your machine already works on an Arduino Opta. WireTight boards clamp under its screw terminals and put every terminal on a latching Molex Micro-Fit header. Build each unit with mass-produced, pre-crimped harnesses: no hand-wired terminals, and no replacement board to design, certify and source.
The step between prototype and custom board
A machine proven on an Opta usually reaches production one of two ways: keep hand-wiring screw terminals on every unit, or replace the Opta with a custom embedded board. WireTight is the step in between, or instead.
Opta + Micro-Fit harnesses
Same Opta, same program. Boards clamp under the terminals; standard Micro-Fit harnesses plug in. Harnesses are built and tested in batches, off the machine.
Typical lead time: days to weeks
Your own controller board
Replaces the Opta. Schematic, layout, prototype spins, firmware port, EMC and safety testing, component sourcing. Lowest unit cost once volume is high and the design has settled.
Typical lead time: months
| Hand-wired Opta | Opta + WireTight | Custom controller PCB | |
|---|---|---|---|
| Controller | Opta | Opta | New board you design |
| PLC program | As is | As is | Ported to new hardware |
| Wiring per unit | Every wire by hand | Plug in harnesses | Plug in harnesses |
| Harnesses | Built on each unit | Standard Micro-Fit, built in batches | Made to your board |
| Engineering first | None | Pick a kit per module | Design, prototypes, testing |
| Controller approvals | Arduino's | Arduino's | Yours to obtain |
| Time to production | Now, slow per unit | Typically days to weeks | Typically months |
| Best fit | Prototypes, one-offs | Pilot runs to steady production | High volume, settled design |
Times are typical ranges, not quotes. WireTight's depends mostly on your harness supplier; a custom board's on its scope and certification.
Screw terminals are fine on the bench. Not on a robot.
The Opta is a great controller to build on. Its screw terminals are where production slows down and field problems start: every unit is wired by hand, and vibration and rework add up to intermittent faults that are hard to find after you ship.
Locks, doesn't loosen
Molex Micro-Fit connectors latch positively and resist vibration. No more re-torquing terminals after every test run.
Swap a controller in seconds
Unplug the harnesses, unclip the Opta from the DIN rail, clip in a new one and plug back in. No terminal-by-terminal rewiring on a service call.
Wire it right, every time
Polarized, keyed connectors mean your harness only goes in one way. Build harnesses on the bench, test them, and ship with confidence.
Mass-produced harnesses
Micro-Fit 3.0 is a standard Molex connector: any harness shop can build to it, and pre-crimped leads are stocked by distributors. Your assembly step becomes "plug in."
No custom PCB to wait for
Keep the Opta and your existing program. No schematic, layout, prototype spins or component sourcing before you can ship.
Start bare, switch later
Prototype with the bare-hole boards and your own connector, then move to Micro-Fit when your design settles.
| Hand-wired screw terminals | WireTight board | |
|---|---|---|
| Wires landed per Opta | 20 individual wires | 2 connectors |
| Harness build | By hand, on each unit | In batches, by any harness shop |
| Controller swap time | Rewire every terminal | Unplug, swap, plug in |
| Vibration resistance | Screws can back out | Positive-latch connector |
| Miswire risk | Any wire in any terminal | Keyed, one-way mating |
| Harness testing | After install | On the bench, before install |
One kit per module. Three ways to buy.
Every kit covers all of a module's terminal rows. Pick bare boards for your own connectors, boards with Molex Micro-Fit installed, or the full kit with standoffs and, for expansion modules, the power jumper.
Bring your own connector
Every terminal comes out to a row of plated holes on a 2.54 mm (0.1″) pitch. Solder in any 0.1″ pin header, latching 2.54 mm header or terminal block, or wire directly.
Molex Micro-Fit 3.0
Polarized, latching right-angle headers, installed. Mate them with standard Micro-Fit receptacle harnesses. Relay outputs are rated 5 A DC per channel with 18–20 AWG harness wire.
Pull-up / pull-down
Every digital input on B001 and B002 has plated holes for a ½ W axial resistor you fit yourself, lying flat on the board: a pull-up for NPN / open-collector sensors, or a pull-down for 2-wire sensors that leak. Nothing is fitted, so you pick the value your sensors need.
Standoffs and power jumper
Stacked boards bolt together through their corner holes with 17 mm M3 standoffs; Boards with nothing stacked on them (B001's two, and T1 in B003) get 20 mm standoffs to the back panel in the full kit. Expansion kits add a Micro-Fit power jumper that carries the supply over from the board next door.
Shop
Select the Arduino module you have. The SKU (AFX…) is printed on its label.
Accessories
Building more than 25 units? Ask about volume pricing and pre-built harnesses.
Specifications
| Set | Fits | Boards | Micro-Fit headers | Stacking |
|---|---|---|---|---|
| B001 | Opta RS485 / WiFi / Lite | T1 + + − −, I1–I8 · T2 relays 1–4 (5 A DC) | 2× 2×1 power, 2×4, 1×8 | none |
| B002 | Opta Ext D1608E / D1608S | T1 + + − −, relays 1–2 · T2 I1–I10 · T3 I11–I16 · T4 relays 3–8 | 6× 2×1 power, 2×2, 2×5, 2×3, 1×12 | T2 on T1, T3 on T4 |
| B003 | Opta Ext A0602 | T1 + + − −, analog 1–2 · T2 PWM 1–4 · T3 analog 3–6, outputs 1–2 | 2× 2×1 power, 2×3, 2×3, 2×6 | T2 on T3 |
All boards: plated 2.54 mm hole rows on every board (bare kits ship without connectors). Relay outputs are DC only: 5 A per channel, 60 V max, and never above the Opta's own DC rating (4 A at 30 V). Full pinouts on each set's page.
Install in three steps
- Seat the board on the Opta's terminal row.
- Tighten the terminals once to clamp the board's pins.
- Plug in your harness. From now on, that's the only step.
FAQ
Why not design a custom board to replace the Opta?
You can, and at high volume it may cost less per unit. It also means schematic and layout, prototype spins, porting your program, EMC and safety testing, and sourcing every part: typically months before the first production unit. WireTight lets you ship on the Opta you've already proven, while that work happens or instead of it.
Where do the harnesses come from?
Anywhere that builds Molex Micro-Fit 3.0: a harness shop working from your drawing, pre-crimped leads from a distributor, or your own crimp tool. Each set's page has harness sheets for every header: receptacle and terminal part numbers, wire gauge, cavity order and wire colours. Pre-built WireTight harnesses are on the way; get in touch if you need them now.
Do I need to change my Opta program?
No. WireTight boards are passive — they only change how wires connect to the terminals.
Can I switch AC loads with the relay board?
Not at this time. The relay boards are rated for DC loads only: up to 5 A per channel and 60 V, within the Opta's own DC breaking capacity (10 A at 24 V, 4 A at 30 V, much less above that).
Which connector should I pick?
Choose Micro-Fit if you want a ready-to-use, latching connector. Choose the bare kit if you already standardize on a different connector: the holes are on a 2.54 mm (0.1″) pitch, so any 0.1″ header or terminal block fits, or you can wire directly.
Do the inputs need pull-up or pull-down resistors?
Sometimes. An open Opta input reads OFF, but NPN / open-collector sensors need a pull-up, and a 2-wire sensor's leakage current can read as ON without a pull-down. B001's input board (T1) and B002's input boards (T2, T3) have three plated holes per input for a ½ W axial resistor that lies flat on the board, with both positions outlined and marked: UP for a pull-up to +24 V, DOWN for a pull-down to GND. Nothing is fitted at the factory. B002's input boards have no supply terminal, so feed their 2-pin power header (J4) from T1. Values and limits are in each set's datasheet.
How do I power an expansion module?
Each set's T1 board has two identical 2-pin power headers. Feed the supply into one, then run a power jumper from the other to the next module's T1. Expansion full kits include one jumper.
Built for machines that move.
Mobile robots, cobots and test rigs shake loose what a bench prototype never would. Lock your controller wiring down before it ships.
Taking an Opta prototype to production?
Tell us about your machine. We're happy to talk volume, custom pinouts or harnesses.
sales@wiretight.com