User manual

6 Detailed descriptions of I/O modules | Serial communication module UR20-1COM-232-485-422
394 1432790000/08/12.2015Manual u-remote
Enabling the data transfer
There are different ways to announce the communication
module to the control. Using the test mode you only copy
the input data into the output data of the module so that the
received data will be sent again. Or you choose one of the
function blocks provided by your engineering tool.
For your own programming please regard the following sche-
mes showing the sequences for receiving and transmission.
START
Read diagnosis
No receive-data
present
no
no
no
yes
yes
yes
Error
save/note!
SPS application error
Segment-sequence error
STATRES = 0
STATRES = 1
STAT=1
RX_CNT
= RX_CNT_ACK
RX_CNT
= (RX_CNT_ACK +1)
MOD4
n = RX_BYTE_CNT
RX-Data = Data byte []
RX_CNT_ACK = RX_CNT
Scheme of the receiving sequence
START
Read diagnosis
no
yes
no
no
yes
yes
STATRES = 0
STATRES = 1
STAT=1
Transmit data
being present?
TX_CNT
= TX_CNT_ACK
Data byte [] = TX-Data
TX_BYTE_CNT = n
TX_CNT = (TX_CNT+1) MOD4
Scheme of the transmission sequence