Hitachi EH-150 Series - Page 50

Chapter6 Communication Mode
6 - 8
Fre
e Protocol
[3] Message composition / Modem line control / Data conversion type
(1) Message composition
Specify message format as below. If message composition is registered, EH-SIO will handle sending / receiving
data automatically according to the setting.
Table 6.2 Registration message composition list
No.
Setup Value
Message composition
1
H00xx
Data only
2
H01xx
Data + Stop character
3
H02xx
Data + Check code *
1
4
H03xx
Data + Check code + Stop character *
2
5
H04xx
Data + Stop character + Check code
6
H10xx
Start character + Data
7
H11xx
Start character + Data + Stop character
8
H12xx
Start character + Data + Check code *
1
9
H13xx
Start character + Data + Check code *
1
+ Stop character
10
H14xx
Start character + Data + Stop character + Check code *
2
-
Others
Initial setting error
*1 Check code is calculated for a data part.
*2 Check code is calculated for a data part and a stop character part.
When a start character is not specified, EH-SIO will start receiving by any data. When a stop character is not
specified, EH-SIO will stop receiving by interval time.
Reference : Message composition
If message composition is registered, only data part is handled by user program. The message composition of
start character (STX) + data + check code + stop character (CR) is explained with the example below.
Data sending:
Data receiving:
As shown in the above figure, the other part than data is handled by EH-SIO.
(2)
(3)
(1)
1 word
Data
STX
Check code
CR
: Added by EH-SIO
Automatic generation of check code from data part
Data from CPU module
Data
STX
Check code
CR
Sent data from EH-SIO
Data
STX
Check code
CR
: Taken by EH-SIO
Data and check code are checked automatically.
Received data by CPU module
Data
STX
Check code
CR
Received data by EH-SIO