epc100

Overview Functional Description

Light Curtain Receiver in a 2-Wire Configuration

VDD

VDD

VDD

VDD

AN epc100 light curtain receiver

LST

VDD33

I

F

epc100

GND

SO

SCK

SI

CS

µC

GND

VDD µC

VDD

PD

VDD33

R

1

epc100

GND

18.05.2011

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.

VDD18

PD

VDD33

R

2

epc100

GND

VDD18

PD

VDD33

R

n

epc100

GND

VDD18

Rx Element 1

Rx Element 2

Rx Element n

R

TE

I

TE

Figure 4: Typical light curtain receiver edge circuit

The epc100 device can be operated in two different modes:

a) Photo Current Receivers

It detects current pulses of the photo diode generated by light pulses and transmits the information using the 2-wire bus to a central con-

b) 2-Wire Bus Interface of the Central Controller

It manages the 2-wire bus traffic between the micro controller and the individual photo current receivers. The device operating as the inter-

From the point of view of the micro controller, the whole system looks like a single device with several addressable photo diodes. The micro

controller activates one photo diode and fetches the results after a predefined time. Each sensor device has two different operation modes: A

standby and an operating mode. During the standby mode the power consumption is reduced and the DC current generated in the photo di -

ode is shorted. During the operation mode, the micro controller addresses one device after the other and fetches the result. The result con -

tains the information whether a light pulse has been received in a predefined receive window or not. It also contains the time point when the

light pulse has been received in respect to the receive window.

The receiver channel detects current pulses which are generated by light pulses in the photo diodes. The detection circuitry has two trigger

levels, hereinafter called thresholds, which form a digital signal from the analog current change. The lower threshold is called OUTN (normal)

whereas the upper level is called OUTH (high). Both trigger thresholds can be configured individually per chip. Please refer to Figure 2 and to

the Reference Manual epc10x which contains the configuration information.

© 2011 ESPROS Photonics Corporation

Characteristics subject to change without notice

5

Datasheet epc100 - V2.1

www.espros.ch