Specifications

45
Message Transmission of Data Section 5-8
5.7.3 Coordination Flag
A flag bit is specified in the message header which is used by the receiving device
to monitor the receipt of data.
The monitoring function is deactivated if the value for the coordination flag is FF
16
,
FF
16
.
If a coordination flag is specified, it will be set in the passive partner upon receipt of
data.
Once this flag has been set, processing of the data received will be initiated.
After the data have been processed, the flag will be reset again.
If this flag is still set upon the receipt of data, the passive partner will transmit a
response message to the active partner thereby indicating the respective error.
NOTE:
For connections to a Siemens communications module CP524/525, the coordina-
tion flag in DB1 must be entered into the list of interprocessor communication flags.
5.7.4 Structure 4-Byte Sized Response Message
Function ASCII Hex Comment
1. Byte Message 00 always 00
2. Byte identifier 00 always 00
3. Byte always 00
4. Byte Error code xx
5.8 Message Transmission of Data
Terminal
active partner
transmit
.
passive partner
STX
.
,
DLE
Message header
.
Data
.
DLE
.
ETX
.
BCC (selectable)
.
,
DLE
,
STX
DLE
.
,
Response Message
,
DLE
ETX
,
BCC
DLE
.