Siemens S5-100U - Page 427

S5-100U Function Modules
• Diagnostic Byte (Byte 1)
The diagnostic byte is byte 1 of the first input word. Byte 0 has no significance.
The diagnostic byte provides information on the following items:
- Preset position resolution
- Preset mode
- Status of setpoints
- Signal status of the sync bit for position decoding
Figure 15-15. Diagnostic Byte
* If the sync bit is not set, a reference point approach must be implemented before operation
can continue in the Position Decoding mode.
Bit No.: 76543210
Position resolution
single
double
quadruple
not possible
Mode
Position decoding
Counter
Counter overflow
No counter overflow
Setpoint 2 reached
Setpoint 2 not reached
Setpoint 1 reached
Setpoint 1 not reached
Sync bit set
Sync bit not set *
X = irrelevant
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
R P/C OV S
2
S
1
SyRX
15-26 EWA 4NEB 812 6120-02