Ee895 Connected To A Knx Bus; Digital Interface; C Interface; Modbus Protocol Over I C Interface - E+E Elektronik EE895 User Manual

Miniature sensor module for co2, temperature and barometric pressure
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3.7.3.

EE895 Connected to a KNX Bus

Fig. 11
Example KNX Bus
Pin 7 - ISEL is connected to the ground → the EE895 features I
The VCC_EM and the VCC_IO are connected to the typical 5 V bus voltage.
2
The I
C host keeps the EE895 enabled with the pin 3 – EN and can read the values at any time, pin 6 - RDY is
not used.

4 Digital Interface

The EE895 features standard I
Tab. 2 Interface selection. On both interfaces, I
Units (Modbus PDUs).
PLEASE NOTE
Modbus implementation details and request/response examples are described in detail in the Modbus
Application Note AN0103 (available at www.epluse.com/ee895).
2
4.1
I

C Interface

The EE895 supports the standard I
to NXP document „I
https://www.nxp.com/docs/en/user-guide/UM10204.pdf
2
The I
C interface simultaneously supports two protocols on two different slave addresses:
Modbus over I
2
I
C simplified
These addresses are fixed, they cannot be changed by the user.
4.1.1.
Modbus Protocol Over I
2
I
C slave address: 0x5F
2
The I
C interface encapsulates the data according Modbus PDU packets, including CRC:
S
Slave Address
S
Slave Address
Every byte of the Modbus PDU and the Modbus CRC must be acknowledged (according to I
shown above).
2
C and UART interfaces. The interface selection is made with pin 7 – ISEL, see
2
C specification. For detailed information about the I
2
C-bus specification and user manual", Rev. 6, 4 April 2014:
2
C
address 0x5F
address 0x5E
2
C Interface
W
A
R
A
2
C interface.
2
C and UART, the data is encapsulated in Modbus Protocol Data
Request: Modbus PDU + Modbus CRC
Response: Modbus PDU + Modbus CRC
Miniature Sensor Module for CO
User Manual EE895
2
C interface, please refer
P
P
2
C specification, not
, Temperature and Barometric Pressure | 13
2

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