# ANSI/IEEE optical tachometric dynamo symbol

Canonical URL: https://eloragrid.ai/symbols/ansi-optical-tachometric-transducer
Publisher: Elora Grid
Updated: 2026-10-28
Lookup label: TO
Drawing use: Schematic
Reference families: IEEE / ANSI, Manufacturer

## Symbol convention

Convention: IEEE / ANSI
Form: Autodesk IEEE-oriented Instrumentation and Sensors form: Tachometric Dynamo - Optical Type
Autodesk publishes this block under its IEEE Symbol Preview. The counterpart is the matching functional concept in the library; no equivalence of every detailed standard graphic is asserted.
Related representation: [Optical tachometric transducer](https://eloragrid.ai/symbols/iec-optical-tachometric-transducer)

IEEE-library optical tacho form for a speed sensor reading a slotted disc or reflective mark with light.

## In plain English

### What does ANSI/IEEE optical tachometric dynamo mean?

The optical form represents a speed sensor that detects light interrupted by a slotted disc or reflected from a mark on the shaft. It is common on encoders and non-contact speed checks, and its output is normally a pulse train passed to a counter, drive or speed relay.

### A simple example

Optical sensors need a supply for the light source and are sensitive to dirt and alignment. The symbol does not show resolution, supply voltage or output stage type, so those details should be taken from the sensor data and the receiving input.

### What the drawings help you do

Check supply and output stage type against the receiving input. Note resolution in pulses per revolution. The optical form identifies a light-based pickup; the impulse form identifies a pulse output without fixing the sensing principle.

### This particular reference

IEEE-library optical tacho form for a speed sensor reading a slotted disc or reflective mark with light. The optical form identifies a light-based pickup; the impulse form identifies a pulse output without fixing the sensing principle.

### Terms

- Normally open / normally closed: The contact state in the normal condition defined for the drawing.
- Coil: A wound conductor that can produce a magnetic field when energised.
- Signal: Electrical information passed between devices, rather than necessarily the main power supply.

Concept diagram: Identify the device and form → Read the connections and state → Check the equipment reference
A guide to reading this reference. The original symbol illustration and its drawing notes appear below; these boxes are not a wiring diagram.

- [Autodesk IEEE Symbol Preview — Instrumentation and Sensors](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F44D5059-4728-40BD-B9BA-0DE7CFDFAACF.htm)
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/)


## What it represents

The optical form represents a speed sensor that detects light interrupted by a slotted disc or reflected from a mark on the shaft. It is common on encoders and non-contact speed checks, and its output is normally a pulse train passed to a counter, drive or speed relay.
Optical sensors need a supply for the light source and are sensitive to dirt and alignment. The symbol does not show resolution, supply voltage or output stage type, so those details should be taken from the sensor data and the receiving input.

## How to read it

- Check supply and output stage type against the receiving input.
- Note resolution in pulses per revolution.

## Information to show or reference

- State resolution
- Show sensor supply
- Reference the counting input

## Important distinction

The optical form identifies a light-based pickup; the impulse form identifies a pulse output without fixing the sensing principle.

## Facts

- Convention evidence: Autodesk IEEE Symbol Preview, Instrumentation and Sensors
- Public vendor block name: HIN1B13 / VIN1B13 (Autodesk identifier; not an IEEE symbol number)
- Sensing principle: Interrupted or reflected light
- Artwork scope: Original functional illustration; exact standard glyph and compliance are not certified

## Public references

- [Autodesk IEEE Symbol Preview — Instrumentation and Sensors](https://help.autodesk.com/cloudhelp/2021/ENU/AutoCAD-Electrical/files/GUID-F44D5059-4728-40BD-B9BA-0DE7CFDFAACF.htm) — Autodesk. Public IEEE-oriented Instrumentation and Sensors preview listing the Tachometric Dynamo - Optical Type block and its vendor identifier.
- [IEEE/ANSI 315-1975: graphic symbols for electrical and electronics diagrams](https://standards.ieee.org/ieee/315/515/) — IEEE Standards Association. Graphic-symbol standards context and official status; not a source of reproduced artwork.

## Graphic scope

Independent original educational concept illustration by Elora Grid. Not a certified standards graphic or manufacturer footprint. Unitless; not to scale. Original artwork licence: https://creativecommons.org/licenses/by/4.0/. Publisher material is linked only.