2 io data mapping, 1 io data assignment of il230x and extension boxes – BECKHOFF ILxxxx-B520 User Manual
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IO Data Mapping
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ILxxxx-B520
2 IO Data Mapping
IO Data Mapping
The IO Data Mapping describes the contents of the IO Data of the ILxxxx-
B520 in Receive and Transmit direction. The description is done by De-
viceNet Assembly Objects. Each of the ILxxxx-B520 supports Assembly
Objects in each data direction. The input data/status or output data is map-
ped to a byte stream exchanged with the DeviceNet Master / Scanner by
IO-Data transfer.
2.1 IO Data Assignment of IL230x and Extension Boxes
Digital Signals
(bit-oriented)
The digital Signals are bit-oriented. This means that one bit in the process
image is assigned to each channel. The ILxxxx-B520 creates a memory
area containing the current input bits and ensures that the bits in a second
memory area dedicated to the output channels are written out immediately
Analog Signals
(byte-oriented)
The processing of analog signals is always byte-oriented. Analog input and
output values are represented in memory by two bytes each. Values are
represented in unsigned/signed integer or two’s complement format ( see
IExxxx manual). The number “0” stands for the input/output value “0 V”, “0
mA” or “4 mA”. Per default, Control and Status Bytes for each analog
channel are not mapped to the IO-data image. An analog channel is repre-
sented in the process image by two bytes
Special Signals and inter-
faces
(byte-oriented)
The ILxxxx-B520 supports extension boxes with other interfaces such as
RS232, RS485 incremental encoder, SSI Sensor interface. These signals
can considered similarly to the analog signals named above. For some
special signals the width of 16 Bit is not sufficient. The IL230x can Support
any byte width.
Assignment of inputs/ out-
puts to the process image
(Default Assignment / As-
sembly Object)
Once it has been switched on, the ILxxxx-B520 finds out how many Exten-
sion Boxes are connected and creates an assignment list. The analog and
digital channels, divided into inputs and outputs, are assembled into differ-
ent parts of the list. The assignment starts on the first extension box next to
the ILxxxx-B520. The software in the ILxxxx-B520 collects the individual
entries for each of the channels in order to create the assignment list.