BECKHOFF C1220 - Manual (Page 19)

Eiserstraße 5 / D-33415 Verl / Telefon 05246/963-0 / Telefax 05246/963-149
19 Software description of functions
Beckhoff Lightbus - PC interface card C1220
Example:
Initialization of communication 3 as free communication with 2 telegrams.
The base address for the output area is 0x400, and the base address for
the input area is 0x210.
Argument Channel Length Function blank
0 1 2 3
Request 09 0x0b 00 03 02 00,04 10,02
Channel Length Function Argument 0 Comment
Reply 03 0x0b 00 ok
By means of this structure it is also possible to modify the module address
and the control byte during the run time. One restriction here, however, is
that this must not take place while communication is active.
Cyclic communication
With the function 0x12, it is possible to trigger communication cyclically by
the central module. In doing so, the otherwise necessary Handshake by
way of the GCB is dropped.
Channel Length Function Argument 1 Argument2
Request 04 0x12 k pan
Channel Length Function Argument 0 Comment
Reply 03 0x12 00 ok
03 0x12 01 Error
where: pan Process image number
k Status
0 = Communication passive
1 = Communication active
In this mode of communication, however, only byte-oriented I/O functions
should be executed because the timing behavior is no longer deterministic.
Transmitting the interrupt mask
The module C1220 features 4 interrupt channels through which the
address-independent interrupts are transferred to the PC. Transfer to the
PC is realized via the GCB.
The address-independent interrupts can be generated by the peripheral
modules. In doing so, they are inserted in the interrupt field of the control
byte.
The function 0x0f is used to communicate to the module C1220 which
interrupt channels are to be activated and which interrupt criteria are to
lead to interrupt transmission to the PC.