Hitachi Hidic EH-150 Applications Manual page 61

Preliminary Rev.03
Optional sending
Transmitted data is refreshed only when EH-ETH receives a certain command from user program, otherwise EH-
ETH transmits previous data cyclically. The outline of CPU and EH-ETH is shown in Fig.7.3.1.2, and the time
chart is shown in Fig. 7.3.1.3.
(A) Only when EH-ETH receives a command X, EH-ETH requests designated data every cycle.
(B) CPU receives the request and sends the data to EH-ETH.
(C) [In case EH-ETH receives X] EH-ETH stores the received data and transmits to the Ethernet line.
[In case EH-ETH does not receive X] EH-ETH transmits the previous data.
(X) CPU (user program) send a request "Send data to Ethernet line" to EH-ETH.
Cycle time
Sent data
Data refresh
Data in CPU
- Description in this manual might be modified without notice.
EH-CPU448
Transmission area
Ethernet
Fig. 7.3.1.2 Cyclic sending (optional sending enabled)
0
A
Fig. 7.3.1.3 Time chart ("Optional sending" enabled)
7-14
Chapter 7 Automatic data transmission
EH-ETH
Transmission buffer
(X)
(A)
(B)
(C)
Description
B
B C D
D E
E F