User manual
Transferring Data with the I/O Scanner
202
33002479 06 07/2008
Device Control 
Block
Important information about using the Device Control Block:
Registers The Device Control Block consists of registers either eight (8) 
single words or four (4) double words. Contents of the registers 
are mapped in the controller’s memory. Each bit corresponds to 
an entry in the table (see the tables below.)
Disabling Devices Each I/O Scanner device can be disabled. To disable individual 
devices:
1. Select the Device Control Block option on the I/O Scanner tab 
in Unity Pro. (Insert a check mark in the box.)
2. Set the associated bit = 1.
Mapping Device Control 
Block Bits to I/O Scanner 
Entry Numbers (#)
See the table for mapping entry numbers to bits.
Each entry number represents a logical device on the network.
Setting Bits If Device Control Block bit is set to
z 0 = Device is enabled
z 1 = Device is disabled










