---
name: "counter"
section: "9"
platform: "linux"
package: "linuxcnc-uspace"
version: "1:2.9.4-2+deb13u1"
release: "Debian 13 (Trixie)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/counter/9"
---

# counter(9)

counts input pulses (DEPRECATED)

## NAME

counter - counts input pulses **(DEPRECATED)**

## SYNOPSIS

**loadrt counter \[num\_chan=*N*\]**

## DESCRIPTION

**counter** is a deprecated HAL component and will be removed in a future release.  Use the **encoder** component with encoder.X.counter-mode set to TRUE.

**counter** is a HAL component that provides software- based counting that is useful for spindle position sensing and maybe other things.  Instead of using a real encoder that outputs quadrature, some lathes have a sensor that generates a simple pulse stream as the spindle turns and an index pulse once per revolution. This component simply counts up when a "count" pulse (phase-A) is received, and if reset is enabled, resets when the "index" (phase-Z) pulse is received.

This is of course only useful for a unidirectional spindle, as it is not possible to sense the direction of rotation.

**counter** conforms to the "canonical encoder" interface described in the HAL manual.

## FUNCTIONS

- **counter.capture-position (uses floating-point)**

  Updates the counts, position and velocity outputs based on internal counters.

- **counter.update-counters**

  Samples the phase-A and phase-Z inputs and updates internal counters.

## PINS

- **counter.*N*.phase-A bit in**

  The primary input signal.  The internal counter is incremented on each rising edge.

- **counter.*N*.phase-Z bit in**

  The index input signal.  When the **index-enable** pin is TRUE and a rising edge on **phase-Z** is seen, **index-enable** is set to FALSE and the internal counter is reset to zero.

- **counter.*N*.index-enable bit io**

  - **counter.*N*.reset bit io**

  - **counter.*N*.counts signed out**

  - **counter.*N*.position float out**

  - **counter.*N*.velocity float out**

  These pins function according to the canonical digital encoder interface.

- **counter.*N*.position-scale float rw**

  This parameter functions according to the canonical digital encoder interface.

- **counter.*N*.rawcounts signed ro**

  The internal counts value, updated from **update-counters** and reflected in the output pins at the next call to **capture-position**.

## SEE ALSO

**[encoder(9)](/encoder/9.md)**. in the LinuxCNC documentation.