PLEASE NOTE: This article is obsolete or related to a discontinued product.

DAISY-18 - 4 channel industrial range optoisolated input (0-48 Volt)

DAISY-18 is a four opto-isolated digital inputs board.

Main features

  • 4 input channels
  • Max input voltage: 48 Volt
  • Max input current:
    • 15mA @ 24V
    • 18mA @ 48V
  • Schmitt trigger input :
    • Low level input threshold: 10.5V
    • High level input threshold: 16V
  • Isolation voltage: 2500 Vrms (max)

The daisy connectors where to plug this board are:

Board Daisy Connector
FOXG20 D2
FOXG20 D5
TERRA D11
TERRA D12

On the FOX Board G20 is requested a Daisy-1 adapter.

General Layout

The following picture shows Daisy-18 connectors and monitoring LEDs.

Connecting to a Daisy-1

Up to 2 Daisy-18 boards can be connected to the same Daisy-1 connector by means of the Replicator connector J3. So full use of all I/O pins on a single Daisy-1 connector is made. This applies to Daisy-1 connectors: D2, D3, D5 provided all pins are set as GPIO.

Daisy-18 cascading feature is illustrated by the following picture :

Different ways to connect a Daisy-18

The "floating" optoisolated inputs of the Daisy-18 handle the following configurations

Sink mode (aka NPN)

Up to 4 switches can be read in this configuration.

Source mode (aka PNP)

Up to 4 switches can be read in this configuration.

Mixed modes are easily handled by Daisy-18 as shown in the following case list:

Case A

  • Input 1 : Sink mode
  • Input 2 : Sink mode
  • Input 3 : Sink mode
  • Input 4 : Sink mode

Case B

  • Input 1 : Sink mode
  • Input 2 : Sink mode
  • Input 3 : Sink mode
  • Input 4 : Source mode

Case C

  • Input 1 : Sink mode
  • Input 2 : Sink mode
  • Input 3 : Source mode
  • Input 4 : Source mode

Case D

  • Input 1 : Sink mode
  • Input 2 : Source mode
  • Input 3 : Source mode
  • Input 4 : Source mode

Case E

  • Input 1 : Source mode
  • Input 2 : Source mode
  • Input 3 : Source mode
  • Input 4 : Source mode

Programming examples

Following there are some examples of code on how to use the Daisy-18 board.

Get the input state from one module:

read4.py

Get the input state from two modules wired on the same daisy connector:

read8.py

Schematics, datasheets and related links