> For the complete documentation index, see [llms.txt](https://docs.efento.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.efento.io/efento-ble-loggers/installation/logger-specific-installation-guidelines/4-20-ma-loggers-wiring.md).

# 4-20 mA loggers wiring

Efento 4–20 mA loggers are designed to measure the output of 4–20 mA sensor probes and transmit data over NB-IoT networks to Efento Cloud or any other server. Each logger can support up to three analog channels, compatible with 2-wire probes, 3-wire PNP/NPN probes, and 4-wire probes.

{% hint style="info" %}
The loggers can supply power (up to **16 V**) to connected passive probes (2-wire, 3-wire PNP/NPN, and 4-wire). Alternatively, 2-wire, 3-wire PNP, and 4-wire probes may be powered by an external source (active mode). **3-wire NPN probes cannot be powered externally**.
{% endhint %}

Efento 4–20 mA loggers measure currents within the **−24 to 24 mA** range, with a resolution of **0.001 mA**. The shunt resistance (Rs) is **3 Ω**.

### Channel Configuration

Each channel can be configured for the required probe type using jumpers on the PCB:

* **Channel 1:** Jumpers J1, J2
* **Channel 2:** Jumpers J5, J6
* **Channel 3:** Jumpers J3, J4

#### Jumper Settings

{% hint style="danger" %}
Warning! Always power off the device before changing jumper settings or wiring sensor probes.
{% endhint %}

| Probe Type              | Channel 1 (J1/J2) | Channel 2 (J5/J6) | Channel 3 (J3/J4) |
| ----------------------- | ----------------- | ----------------- | ----------------- |
| **2-wire, passive**     | open / closed     | open / closed     | open / closed     |
| **2-wire, active**      | open / open       | open / open       | open / open       |
| **3-wire PNP, passive** | open / closed     | open / closed     | open / closed     |
| **3-wire PNP, active**  | open / closed     | open / closed     | open / closed     |
| **3-wire NPN, passive** | closed / open     | closed / open     | closed / open     |
| **4-wire, passive**     | open / open       | open / open       | open / open       |

{% hint style="danger" %}
**Warning:** Never set the jumpers to the closed/closed position (J1 & J2 closed, J3 & J4 closed, or J5 & J6 closed). This configuration may damage the device.
{% endhint %}

### Wiring

Efento 4–20 mA loggers include a 12-input terminal block. Each terminal is labeled on the PCB (V1–V3, I1–I3, O1–O3, G1–G3), indicating both the channel number and input type. Wiring varies depending on the probe type:

#### **2-wire probe powered by Efento logger (passive)**

<figure><img src="/files/aKAH3zE1JU4WIUDTrr4o" alt=""><figcaption></figcaption></figure>

#### **2-wire probe with external power supply (active)**

<figure><img src="/files/0tyea0AtNPnsfgbl05UX" alt=""><figcaption></figcaption></figure>

#### **3-wire PNP probe powered by Efento logger (passive)**

<figure><img src="/files/vxlK35S7vVgLw59VjYFx" alt=""><figcaption></figcaption></figure>

#### **3-wire PNP probe with external power supply (active)**

<figure><img src="/files/uUgPsb1yFdwIXJqnFXJY" alt=""><figcaption></figcaption></figure>

#### **3-wire NPN probe powered by Efento logger (passive)**

<figure><img src="/files/RSKEVhPeu1vuZhRseRqB" alt=""><figcaption></figcaption></figure>

#### **4-wire probe powered by Efento logger (passive)**

<figure><img src="/files/dvHPlZyXqjsBpsLQuvzC" alt=""><figcaption></figcaption></figure>


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