Omron C200H-MC221 Operation Manual page 77

I/O Transfer Timing
1, 2, 3...
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. 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 (Between the transmission control bit turned ON and the
1 0.04
10 0.06
100 0.18
500 0.89
1000 1.6
Transmission time (s)
next transmission control bit turned ON)
Section 4-7
57