57
Set the number of transfer words, data source word, and data destination
address in the expansion data area and turn the transmission control bit (word
n+1, bit 11) ON for I/O transfer.
The MC Unit performs the following and turns the Transmission Completed Flag
(word n+8, bit 6) ON.
1, 2, 3... 1. The MC Unit obtains parameters (the number of transfer words, data source
word, and data destination address) to turn the transmission control bit ON.
It takes a few cycles to obtain the parameters.
2. The MC Unit obtains transmission data from the PC. Transmission data of
20 words max. can be obtained at a time. If the number of words of the trans-
mission data exceeds 20, the remaining transmission data is obtained in
sequence in blocks of 20 words.
It takes a few cycles to obtain the 20-word transmission data.
3. The MC Unit checks whether the transmission data is correct after receiving
the first block of data. It takes a few milliseconds to check this.
4. The MC Unit repeats steps 2 and 3 described above until the MC Unit
finishes checking all the transmission data.
5. The MC Unit turns the Transmission Completed Flag ON after data trans-
mission. It takes a few scans to turn the Transmission Completed Flag ON.
The calculation of transmission time is complicated. Refer to the following exam-
ple of transmission time with the C200HS as a reference value.
Cycle time: 4.2 ms
Status of MC Unit: 1 task with 2 axes that are servo-locked.
No. of position
data items
Transmission time (s)
(Between the transmission control bit turned ON and the
next transmission control bit turned ON)
1 0.04
10 0.06
100 0.18
500 0.89
1000 1.6
I/O Transfer Timing
Section 4-7
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