Addressing The Inputs And Outputs, Data Access; Basic Rules For Addressing; Differences In Addressing Between The Modular Device Profile And Fixed I/O Size - Festo CPX-FB37 Translation Of The Original Instructions

4 Commissioning
Detailed information on the electric and pneumatic CPX modules can be found on the
Festo website (
4.3

Addressing the inputs and outputs, data access

4.3.1

Basic rules for addressing

– The bus node counts as a module with 0 inputs and 0 outputs when the status bits and the I/O dia-
gnostic interface are deactivated.
– Observe the notes regarding address assignment in section 4.2.
– Modules with less than 8 bits occupy 8 bits or 1 byte of address space, but do not use all this space.
– The addressing sequence differs between MDP and a fixed I/O size (CPX-FB38 mode).
If necessary, status bits or the I/O diagnostics interface can be activated via DIL switch
( Tab. 3.3):
– If the 8 status bits are activated, they will occupy 16 inputs in the address range
(8 used).
– If the I/O diagnostics interface is activated, it will occupy 16 inputs and outputs in the
address range.
4.3.2

Differences in addressing between the modular device profile and fixed I/O size

Sequence of addressing — Modular Device Profile (CPX-FB37 mode)
The I/O addresses are assigned in ascending order according to the module position.
Sequence of addressing — fixed I/O size (CPX-FB38 mode)
If the bus node is set to a fixed I/O size using DIL switch 2 (
apply ( Tab. 4.1):
Sequence of addressing
1. Status bits or I/O diagnostics
interface
2. Analogue modules
3. Technology modules
4. Digital modules
Tab. 4.1 Sequence of addressing in CPX-FB38 mode
A detailed description of the addressing process and various addressing examples for the
CPX-FB38 mode can be found in the description of the bus node CPX-FB38
( P.BE-CPX-FB38).
Festo – P.BE-CPX-FB37-EN – 1406NH – English
www.festo.com/sp).
Description
Delivers status and diagnostic information; activate through
DIL switches; occupies the first 16 inputs or inputs and
outputs
Modules with analogue inputs/outputs
e. g. CP interface, front end controller (CPX-FEC), CoDeSys
controller (CPX-CEC)
Modules with digital inputs/outputs
Section 3.2.5), the following rules shall
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