# Connecting

The robot needs three connections to run. They are on the back of the base.

![The power (green), USB (blue) and E-stop (yellow and pink) connections, and the power button (red)](https://docs.source-robotics.com/PAROL-docs/1.1/assets/Connectors.webp){ width="700" }

| Connection | Connector | Notes |
|---|---|---|
| **24 V power** | GX16 2-pin | From the 24 V 5 A supply ([The power supply](#the-power-supply)). Mind the polarity when you wire your own cable: the board has no reverse-polarity protection |
| **USB** | USB type B | To the PC. USB does not power the board |
| **E-stop** | Two screw terminals | A normally closed contact between them. Open means stop |

Plug the power supply into the mains through a switch within your reach, a switched socket strip for example: it
is the stop that still works when the PC software has frozen ([Emergency stop](https://docs.source-robotics.com/PAROL-docs/1.1/02-safety/emergency-stop/)).

## The power supply

The robot needs 24 V DC at 5 A or more, into its GX16 socket. There are two good ways to get it: a closed supply
with a mains cable, which needs no mains wiring, or the DIN-rail supply in the BOM, whose mains side you wire
yourself.

!!! danger "Mains voltage kills"
    The mains side of a power supply carries 230 V or 120 V. Never open, wire or touch it while the plug is in
    the socket. If you are not sure how to wire it, use a closed supply (A), or have a qualified electrician wire
    the DIN-rail supply (B).

### A. A closed supply with a mains cable

The simplest safe choice: a closed 24 V supply of at least 5 A (120 W), a desktop power brick with a moulded mains
cable and plug, approved for your country. There is nothing to wire on its mains side. On its 24 V side:

- Its output plug will not fit the robot. Fit a GX16 2-pin plug to its output cable, or make a short adapter
  cable with the brick's mating socket on one end and a GX16 plug on the other.
- Find + and − on the output with a multimeter, and wire + to the GX16 pin that the robot's socket takes to the
  board's +. The board has no reverse-polarity protection.

### B. The Mean Well EDR-120-24 from the BOM

A 120 W DIN-rail supply with screw terminals and no mains cable. From Mean Well's
[EDR-120 datasheet](https://www.meanwell.com/Upload/PDF/EDR-120/EDR-120-SPEC.PDF):

| | |
|---|---|
| Input | 90 to 264 V AC, 47 to 63 Hz |
| Input terminals | FG (earth), AC/L (live), AC/N (neutral) |
| Output terminals | Two −V and two +V, 24 V, 5 A: the robot's cable to one +V and one −V |
| Output adjustment | +V ADJ, 24 to 28 V. The board takes 24 V at most: leave it at 24 V |
| Room around it | 40 mm above, 20 mm below, 5 mm at the sides, at full load |

You need:

- **A mains cable with three wires, earth included, and a moulded plug.** Never a two-wire cable.
- **Wire ferrules** crimped on the stranded ends, so that no strand escapes the terminal.
- **Strain relief:** the cable clamped where it enters, so that a pull on the cable never reaches the terminals.
- **The earth wire always connected,** to FG.
- **An enclosure:** the supply on a DIN rail (TS35) in a closed box, or at least a cover over its terminals, so that no
  live screw can be touched. A plastic box is simplest; a metal one must be earthed as well.

| Terminal | Europe and the UK | USA and Canada |
|---|---|---|
| AC/L, live | brown | black |
| AC/N, neutral | blue | white |
| FG, earth | green-yellow | green |

Other countries can use other colours: check, and do not guess.

**Check before the first power-on**, in this order:

1. The plug is out of the socket.
2. Each wire is in the right terminal, by the table above, with no loose strands; a gentle pull on each wire
   moves nothing.
3. With a multimeter: the plug's earth pin to the FG terminal reads close to 0 Ω.
4. The box or the terminal cover is closed, and the cable is clamped.
5. The robot is not connected yet. Plug in: the supply's DC OK lamp lights. At the GX16 plug, measure 24 V,
   with + and − on the pins the robot's socket expects.
6. Unplug, connect the robot, plug in through the switch within reach.

**If you are not sure about any step, have a qualified electrician wire the supply.**

## The E-stop

The E-stop must be a normally closed contact: pressing it, unplugging it or cutting its wire opens the circuit,
and all of these stop the robot, which is what you want. A normally open button does not work. The control board
has two E-stop connectors on the same input, so a second button can be wired in series.

The kit's button comes with a printed housing and a PG7 cable gland. [Emergency stop](https://docs.source-robotics.com/PAROL-docs/1.1/02-safety/emergency-stop/)
says what happens when it is pressed, and the [Control Board Manual](https://docs.source-robotics.com/PAROL-docs/1.1/board/06-io-and-estop/) has the wiring
diagram.

## The gripper

An electric gripper (SSG-48, MSG) plugs into the M8 connector at the forearm, which carries 24 V and CAN:
[Electric grippers](https://docs.source-robotics.com/PAROL-docs/1.1/end-effectors/). Pneumatic tubes from the valve go to the two push-in
fittings at the base: [Pneumatics](https://docs.source-robotics.com/PAROL-docs/1.1/06-peripherals/pneumatics/).

## Inputs and outputs

The two inputs, two outputs and their supply terminals are on the side of the control board, reachable through
the base: [Inputs and outputs](https://docs.source-robotics.com/PAROL-docs/1.1/06-peripherals/io/).

!!! warning "Nothing else on the programming port"
    The 2×5-pin programming header next to the USB port is for the ST-Link programming adapter only. An ST-Link
    connected with plain jumper wires without the adapter has destroyed boards. See [Firmware](https://docs.source-robotics.com/PAROL-docs/1.1/board/08-firmware/).