252 Fieldbus Communication
WAGO-I/O-SYSTEM 750
750-882 Media Redundancy ETHERNET Controller
Manual
1.5.0
The length of each register is 1 word; i.e., with each access only one word can be
written or read. Following are two examples of how to set the value for a time
overrun:
Setting the watchdog for a timeout of more than 1 second:
1.
Write 0x000A in the register for time overrun (0x1000).
Register 0x1000 works with a multiple of 100 ms;
1 s = 1000 ms; 1000 ms / 100 ms = 10
dec
= A
hex
)
2.
Use the function code 5 to write 0x0010 (=2
(5-1)
) in the coding mask
(register 0x1001).
Table 141: Starting Watchdog
FC
FC16 FC15 FC14 FC13 FC12 FC11 FC10 FC9 FC8 FC7 FC6
FC5
FC4 FC3 FC2 FC1
Bit
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
bin
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
hex
0
0
1
0
Function code 5 (writing a digital output bit) continuously triggers the watchdog to
restart the watchdog timer again and again within the specified time. If time
between requests exceeds 1 second, a watchdog timeout error occurs.
3. To stop the watchdog, write the value 0xAA55 or 0x55AA into 0x1008
(Simply Stop Watchdog register, WD_AC_STOP_SIMPLE).
Setting the watchdog for a timeout of 10 minutes or more:
1.
Write 0x1770 (= 10*60*1000 ms / 100 ms) in the register for time overrun
(0x1000).
(Register 0x1000 works with a multiple of 100 ms;
10 min = 600,000 ms; 600,000 ms / 100 ms = 6000dec = 1770hex)
2.
Write 0x0001 in the watchdog trigger register (0x1003) to start the
watchdog.
3.
Write different values (e.g., counter values 0x0000, 0x0001) in the
watchdog to trigger register (0x1003).
Values following each other must differ in size. Writing of a value not equal to
zero starts the watchdog. Watchdog faults are reset and writing process data is
possible again.
4.
To stop the watchdog, write the value 0xAA55 or 0x55AA into 0x1008
(Simply Stop Watchdog register, WD_AC_STOP_SIMPLE).