# Fluke8845A

A driver for [`InstroDMM`](https://dev.nominal.io/instro/dmm.md) (unstable)

![Fluke 8845A](https://dev.nominal.io/instro/_images/Fluke8845A.png)

The [`Fluke8845A`](https://dev.nominal.io/instro/ref/instruments/instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A.md#instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A "instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A") provides a driver that can be used to instantiate an [InstroDMM](https://dev.nominal.io/instro/dmm.md). It ships in the `instro-unstable` package (`pip install 'instro[unstable]'`) while its API settles.

The 8845A’s default `8845` command set is compatible with the Agilent 34401A, so this driver runs the [`Agilent34401A`](https://dev.nominal.io/instro/ref/instruments/instro.dmm.drivers.agilent_a34401a.Agilent34401A.md#instro.dmm.drivers.agilent_a34401a.Agilent34401A "instro.dmm.drivers.agilent_a34401a.Agilent34401A") driver’s commands, with its own error messages. It supports the same functions: DC/AC voltage, DC/AC current, 2- and 4-wire resistance, range, and digits.

## Meter setup

Make these settings on the meter’s front panel before connecting. Neither can be changed over the remote interface, and the meter keeps both through a power cycle.

> **Warning**
>
> The meter must use the **`8845`** command set. The driver sends Agilent 34401A commands, which the Fluke 45 emulation command set does not accept.

**Select the `8845` command set.** Press **INSTR SETUP**, then **COMMANDS**, then **8845**.

**Over RS-232, select `COMPUTER` mode.** Press **INSTR SETUP**, **PORT IF**, **RS232**, **COMP/TERM ECHO**, then **COMPUTER**. In `TERMINAL` mode the meter echoes every command and prints a `NNN>` prompt, which the driver reads as the reply, so `open()` fails with an error like `Fluke 8845A reported error: *CLS`.

**Over RS-232, match the serial line to instro’s defaults.** In the same RS232 menu, set **BAUD RATE** to 9600, **PARITY DATA BIT** to NONE 8B DATA, **FLOW CONTROL** to NONE, and **EOL** to CR LF. The meter always uses 1 stop bit. To use other settings, pass a [`VisaConfig`](https://dev.nominal.io/instro/ref/library/instro.lib.transports.visa.VisaConfig.md#instro.lib.transports.visa.VisaConfig "instro.lib.transports.VisaConfig") with a matching [`SerialConfig`](https://dev.nominal.io/instro/ref/library/instro.lib.transports.visa.SerialConfig.md#instro.lib.transports.visa.SerialConfig "instro.lib.transports.SerialConfig") instead of a resource string.

## Creating an [`InstroDMM`](https://dev.nominal.io/instro/dmm.md) with [`Fluke8845A`](https://dev.nominal.io/instro/ref/instruments/instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A.md#instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A "instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A")

```python
from instro.unstable.dmm.drivers import Fluke8845A
from instro.dmm import InstroDMM

dmm = InstroDMM(
    name="myDMM",
    driver=Fluke8845A("ASRL6::INSTR"),
)
```

Parameters and methods specific to [`Fluke8845A`](https://dev.nominal.io/instro/ref/instruments/instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A.md#instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A "instro.unstable.dmm.drivers.fluke_8845a.Fluke8845A") can be found in the [Reference](https://dev.nominal.io/instro/ref.md).