BECKHOFF M2400 - Manual (Page 5)

M2400 Analog Output Beckhoff I/O-System
Date : 11.06.2002 Version : 2.1 Page 5 of 5
2. Function Description Software
The four ports D0..D3 correspond to the data bytes in the FO transmission protocol.
Analog Output
Through the analog channels 1 to 4 of the M2400 analog values of 12 bit resolution are
transmitted in a voltage range of - 10V .. + 10V. The selection of a certain DAC is done by a
logic "0" one of the most significant 4 bits of port D1.
The transmission of the 12 bit data word is done by the least significant four bits of port D1
and the eight bits of port D0.
SELECT PORT D1
MSB LSB
PORT D0
MSB LSB
DAC 1 0 1 1 1 DDDD DDDD DDDD
DAC 2 1 0 1 1 DDDD DDDD DDDD
DAC 3 1 1 0 1 DDDD DDDD DDDD
DAC 4 1 1 1 0 DDDD DDDD DDDD
4 bit
select
low-active
12 bit data
OUTPUT PORT D1
MSB LSB
PORT D0
MSB LSB
+10V SSSS 0 0 0 0 0 0 0 0 0 0 0 0
0V SSSS 1 0 0 0 0 0 0 0 0 0 0 0
-10V SSSS 1 1 1 1 1 1 1 1 1 1 1 1
4 bit
select
low-active
12 bit data