Ads Process Image; Program Transfer; Program Transfer Via The Serial Interface - Beckhoff BC9000 Documentation

Example 1 (default setting)
All the connected Bus Terminals are assigned to the local PLC. The 16 bytes of PLC variables are available
for communication with the ModbusTCP master. PLC variables are part of the byte-oriented data packets,
and can therefore not be accessed by the digital Modbus functions, even though the variables are digitally
mapped in the BCxxxx. Difficulties are most often associated with whether signals are considered as inputs
or outputs. PLC variables that are outputs for the BCxxxx are inputs for the Modbus master, and vice versa.
The default setting can be changed with the KS2000 configuration software (register description table 1
[} 75]).
Local PLC inputs
Modbus Modbus
function address/offset
3 read 0x800...807
6 write 0x800...807
16 write 0x800...807
23 read/write 0x800...807
Example 2
In addition, the Bus Terminals can be assigned once to the BC or to the local PLC. This creates additional
complications in the process image. The rule governing how the process image is assembled is, however,
simple.
• Entry of all the byte-oriented Bus Terminals (such as the analog Bus Terminals)
• Entry of all the digital Bus Terminals (rounded up to 16 bits)
• Entry of the PLC variables
6.7.3

ADS Process Image

16 bytes input and output are assigned to the fieldbus by default in all the BCxxxx devices. These variables
are known as PLC variables, and are located, under the BCxxxx default setting, starting from address 128 in
the process image. The setting can be made with the KS2000 configuration software, or, for some BCs that
support ADS, can be changed by means of start-up parameters.
6.8

Program transfer

6.8.1

Program transfer via the serial interface

The Bus Terminal Controller is programmed using TwinCAT.
The program can also be downloaded to the Bus Terminal Controller via the RS232 interface of the PC. A
special cable, which is included in the scope of delivery of the KS2000 configuration software, should be
used for this purpose.
To this end, select the serial interface in TwinCAT PLC Control.
BC9000 and BC9100
Local PLC outputs
Local Variables Modbus
function
%IB128...%IB143 3 read
4 read
%IB128...%IB143
%IB128...%IB143
%IB128...%IB143 23 read/write
Version: 4.0.0
Programming
Modbus Local Variables
address/offset
0x000...007 %QB128...%QB143
0x000...007 %QB128...%QB143
0x000..007 %QB128...%QB143
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