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IP 240
11.2 Data Transfer from the IP 240 to the S5 CPU
The S5 CPU can request data from the IP 240. To make this possible, you must enter the appropri-
ate job number in the IP's job request register. The IP 240 sets the DFRT bit in the status register
when the requested data are available in the transfer buffer.
In order to prevent errors in a data interchange between IP 240 and S5 CPU, interrupt processing
must be disabled while the data interchange is in progress.
The block diagram below shows the communications procedure for "Read data from the IP 240".
no
yes
yes
EWA 4NEB 811 6120-02a
Start
Disable interrupts and start
200 µs delay timer
Wait time expired?
yes
Read status register
AFRT=1?
no
DFRT=0?
no
Write job number 40
Read status register
AFRT=0?
no
IDLE=1?
no
ERR=1?
no
1
Fig. 11-1. Flowchart for "Read Data from the IP 240"
Direct Data Interchange with the IP 240
yes
Old job terminated?
Reset communication.
H
Channel not yet configured?
yes
If not, generate error message in
STEP 5 program.
yes
Errors detected?
2
Read error codes from IP 240.
11-5
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