EPC100 EPC [Espros Photonics corp], EPC100 Datasheet - Page 5

• Manufacturer Part Number: EPC100
• Description: Light-Curtain Device with 2-Wire Bus Interface
• Manufacturer: EPC [Espros Photonics corp]

Overview Functional Description
Light Curtain Receiver in a 2-Wire Configuration
The epc100 device can be operated in two different modes:
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
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 -
troller, i.e. a micro controller. The devices operating as this photo current receivers are designated in the schematic diagram above as R
R
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-
face unit is designated as I
VDD
VDD µC
GND
n
.
AN epc100 light curtain receiver
µC
R
I
TE
TE
VDD33
SI
SO
SCK
CS
epc100
GND
VDD
F
.
I
F
Rx Element 1
Figure 4: Typical light curtain receiver edge circuit
VDD33
VDD18
PD
epc100
GND
VDD
R
1
Rx Element 2
5
.
VDD33
VDD18
PD
epc100
VDD
GND
R
2
LST
Rx Element n
Datasheet epc100 - V2.1
VDD33
VDD18
PD
epc100
18.05.2011
Page 1
GND
VDD
R
n
www.espros.ch
epc100
1
to