BECKHOFF C1220 - Manual (Page 12)

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Software description of functions 12
Beckhoff Lightbus - PC interface card C1220
Code word
The C1220 outputs the code word after every reset of communication
channel 1. Here, this takes place without setting the Data Valid bit. The
purpose of the code word is to inform the PC that the C1220 interface card
is initialized and ready. The code word can also be queried at any time by
way of the 0x02 function.
Argument Channel Length Function
0 1 2
Comment
Request 02 0x02
Reply 04 0x02 fe af Correct code word
Software version
The version of the EPROM firmware can be queried by way of the 0x03
function.
Argument Channel Length Function
0 1 2
Comment
Request 02 0x03
Reply 04 0x03 xx xx Version xxxx
Evaluation of Parity Errors
If the peripheral modules are fitted with type 132 or BX415
(BK2000) SPROMs, it is possible to localise the sources of parity errors.
The master card produces a “parity error counter” (8 bits wide) for every
module present. This counter works without overflow.
The counter can be read by means of function 04.
Argument Channel Length Function
0 ..
. 128
Comment
Request 03 0x04 00 Transmit counter for modules 0 - 127
Reply 130 0x04 n ..
. y
Counter for modules 0 – 127
(0 = non-localisable parity error)
Request 03 0x04 01 Transmit counter for modules 128 -255
Reply 130 0x04 n ..
. y
Counter for modules 128 -255
Request 03 0x04 02 Reset counter
Reply 02 0x04 Counter reset