L-Card ADC Series, Руководство пользователя

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Chapter 4. Connection of signals.
This section contains information on E-502 connectors, their contacts' purpose and main
characteristics of E-502 inputs and outputs, related to the current connection.
4.1. DGND, AGND circuits
!
AGND is a common wire circuit of isolated analog circuits: ADC inputs and DAC outputs.
DGND is a common cable circuit of isolated digital circuits: digital inputs and outputs.
Inside the E-502 , the AGND and DGND circuits have a common connection point
(figuratively: G1), but these circuits are isolated from GND, USBm Ethernet and E-502 power
input (
fig. 4-1
)
4.2. GND, 0 V, GND_USB, CHASSIS circuits
!
GND is a common wire circuit of digital nodes of E-502 module in the non-isolated part.
0 V is a circuit of the zero potential of the low-voltage E-502 power input.
GND_USB is a common wire circuit of USB interface.
CHASSIS is a circuit for chassis connection (only if E-502 is used without cover – for embedded
application) and signal cables display
Inside E-502 , GND, 0 V, GND_USB, CHASSIS circuits have a common connection point
(figuratively: G2). These circuits are connected to the common wire of the ARM controller and
the non-isolated USB interface (
fig. 4-1
).
Fig. 4-1: Internal connection of the "common wires" circuits in E-502.
4.3. Location of DGND, AGND, GND, 0 V, GND_USB,
CHASSIS circuits on the board
In sub items 4.1 and 4.2the purpose of these circuits is explained, and the figure below shows
schematically their belonging to different functional parts of the E-502.
AGND
DGND
GND
0V
CHASSIS
GND_USB
Фильтр
Гальванический
барьер
G2
G1
Galvanic barrier
Filter