User manual

IEC61131 User and Reference Manual
April 22, 2008
601
Unprotected Write
The Unprotected Write function writes 8 bit values into any area of the I/O database. Access
to the I/O database is limited to the unprotected address range.
Any number of bytes may be written up to the maximum number. The write may start at any
byte address, provided the entire block is within the unprotected address range.
Master Mode
The TeleBUS DF1 protocols may act as a communication master on any serial port. In
master mode, the controller sends commands to other devices on the network.
Simultaneous master messages may be active on all ports.
Function Codes
The table shows the implemented function codes. Note that slave commands at the protocol
layer access the I/O database in physical byte addresses. However, in master mode the
interface to the TeleBUS DF1 protocol accesses the I/O database in physical 16-bit word
registers. The interface function block MSTR and C function master_message are
described in the Sending Messages section below.
The maximum number of 16-bit registers that can be read or written with one message is
shown in the maximum column. The slave device may support fewer registers than shown;
consult the manual for the device for details.
Function
Name
Description
Maximum
00
Protected
Write
Writes words of data to limited
areas of the database.
121
01
Unprotected
Read
Reads words of data from any
area of the database.
122
02
Protected Bit
Write
Sets or resets individual bits
within limited areas of the
database.
1
05
Unprotected Bit
Write
Sets or resets individual bits in
any area of the database.
1
08
Unprotected
Write
Writes words of data to any
area of the database.
121