Siemens SIMATIC NET SPC 4-2 LF Manual page 78

Mode Register 4
Mode register 4 is new in the SPC 4-2 and contains the following bits:
Address
Control
register
31C
H
Bit 0
Bit 1
Bit 3..2
Bit 7
Table 7-16 : Mode Register 4
78
7 6 5
Enab
le-
SPC
4-2
Start-FF-Send
Start for sending a frame (only possible in FF mode)
0 = Sending deactivated (reset value)
1 = The SPC 4-2 starts to send a frame immediately unless it is currently receiving. It
then sends the frame when it has finished receiving. This is only possible when
the FF mode bit is active in mode register 3.
Enable-Takt-Sync
Clock synchronization
0 = Reset value
1 = The SPC 4-2 reacts to global control frames.
Sampling mode
Size of the unsharp window for pulse demodulation
00 Unsharp window 2.5µs to 3.0µs as for the SPC 4-1
=
01 Unsharp window 3.0 µs to 3.5 µs (reset value)
=
10 Unsharp window 3.5µs to 4.0µs
=
11 Unsharp window 4.0µs to 4.5µs
=
Enable-SPC 4-2
Enable SPC4-2 enhancements
0 = Status following reset.
Reading the version number in the status register returns version number "01" of
the SPC 4-1.
When reading the parameter register, the SPC 4-2 does not evaluate address bits
7 to 5 (like the SPC4/SPC4-1).
1 = When the version number is read, the SPC 4-2 returns the version number "10".
Bit Position
4 3 2
Sam Enable-Takt-
pling Sync
mode
PROFIBUS Controller SPC 4®-2 LF
Meaning
1 0
Start Mode-Reg4
_FF-
7..0
Send
C79000-G8976-C157-3