BECKHOFF C1300 - Manual (Page 29)

C1300 VME to II/O Interface Unit Beckhoff II/O-System
Date : 18.12.95 Version : 2.01 Page 29 of 44
Example:
3.4.1. CDL-Communication
A CDL is created for each group of modules, whose signal states are to be activated
together.This CDL consists of so-called descriptors. A descriptor describes a telegram for a
module (message) and is built up as follows:
Bytes Inhalt
0,1 II/O-module addresse (1 - FE)
2,3 Control word :
Bit 4 : 0 = READ; 1 = WRITE
Bit 5 : 1 = address initialization
Bit 6 : 1 = address count command
Bit 7 : 1 = switch to low intensity
4,5 Pointer to byte for output in D0 of a message
6,7 Pointer to byte for output in D1of a message
8,9 Pointer to byte for output in D2 of a message
10,11 Pointer to byte for output in D3 of a message
12,13 Pointer to byte for input in D0 of a message
14,15 Pointer to byte for input in D1 of a message
16,17 Pointer to byte for input in D2 of a message
18,19 Pointer to byte for input in D3 of a message