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06.91
1
2
Structure of the identification in "free message frames"
Characters 1 to 5 are not used.
Error identifier (character 6)
F (error)
=
If a command or message frame is not valid or contains errors, it is
returned to the transmitter with identification "F" entered as the 6th
character.
Command or message frame identifier (character 7)
For "free message frames", a distinction is made between commands and message frames.
Commands are used in the first place for the administration of the interfaces
(reserving/enabling the interface) or for specifically triggering the connected station ("DATA
START"). Commands are generally issued by the user.
7th Character
B=
Command "Reserve interface"
Prior to the actual data transfer, the user must reserve the interface and include the
parameters for addressing in the reverse direction in the useful data before transferring
the data to the interface module. These parameters are "receiver type, address of user
interface, the DB/DX address, DW address".
F=
Command "Enable interface"
On completion of a data transfer, the user must enable the interface to provide access
for other users, too. In the process, the address data stored for this interface are deleted
on the interface module.
The command requires no useful data.
D=
Command "DATA START"
For the XON/XOFF and RTS-LINE procedures (configuration: node states equal: NO),
data input must be initiated by the user via the "DATA START" command.
The command requires no useful data.
© Siemens AG 1989 All Rights Reserved
SINUMERIK 840/880 (PJ)
6.1.2 Meaning of the characters used in the identification of "free message frames"
Characters (in ASCII)
3
4
5
6
6FC5 197-0AB20-0BP0
6 Message Frames
7
8
Block counter
Command or
message frame
identification
Error
identifier
No meaning
6–5
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