Rockwell Automation 8520 9/Series CNC Integration Maintenance Manual Documentation Set - Manual (Page 446)

Section 8
Communication Interface
8-13
Data Receiving Sequence
Figure 8.12 shows the data receiving sequence of the control.
Figure 8.12
Data Receiving Sequence
1 2 3 4 5 6 7 8
Data transmission from a peripheral device (tape reader, etc)
Control codes from the control
DC1 DC3 DC1 DC3
Leader Program Data Program Data MO2
11356-I
DC1 DC1
1. The control transmits the DC1 code in three-second intervals until the
peripheral begins data transmission.
2. Upon reception of the DC1 code, the peripheral begins data
transmission.
3. The control transmits the DC3 code when its buffer cannot accept the
received data.
4. Upon reception of the DC3 code, the peripheral stops data
transmission within two characters.
5. The control sends the DC1 code when it is ready to receive data
again.
6. The peripheral, upon reception of the DC1 code, begins data
transmission again.
7. The control stops data reception when it recognizes the M02 or M30
code and outputs the DC3 code.
8. The peripheral stops data transmission when it receives the DC3
code.