Process Data Architecture For Canopen; Digital Input Modules - WAGO -I/O-SYSTEM 750 Technical Description

5.2 Process Data Architecture for CANopen

With some I/O modules, the structure of the process data is fieldbus specific.
In the case of a CANopen coupler/controller, the process image uses a byte
structure (without word alignment). The internal mapping method for data
greater than one byte conforms to the Intel format.
The following section describes the process imagefor all of the coupler/
controller supported WAGO-I/O-SYSTEM 750 and 753 I/O modules when
using a CANopen coupler/controller.
Note
Depending on the specific position of an I/O module in the fieldbus node,
the process data of all previous byte or bit-oriented modules must be taken
into account to determine its location in the process data map.
In the CANopen object directory the entire input process image can be read
over the index 0x5000 and the entire output process image can be written over
the index 0x5001.

5.2.1 Digital Input Modules

Digital input modules supply one bit of data per channel to specify the signal
state for the corresponding channel. These bits are mapped into the Input
Process Image.
When analog input modules are also present in the node, the digital data is al-
ways appended after the analog data in the Input Process Image, grouped into
bytes. Therefore for each byte one Subindex is occupied.
Some digital modules have an additional diagnostic bit per channel in the In-
put Process Image. The diagnostic bit is used for detecting faults that occur
(e.g., wire breaks and/or short circuits).
1 Channel Digital Input Module with Diagnostics
750-435
For the digital inputs the object 0x6000 (also 0x2000 possible) is used.
WAGO-I/O-SYSTEM 750
CANopen
Bit 7 Bit 6 Bit 5
Process Data Architecture for CANopen
Input Process Image
Bit 4 Bit 3 Bit 2
I/O Modules • 155
Bit 1 Bit 0
Diagnostic bit Data bit
S 1 DI 1