Common MODBUS functions • 297
Diagnostic function
Modular I/O System
ETHERNET TCP/IP
Example:
•
Setting the watchdog for a time overrun of more than 1 s
1.
Write 0x000A (=1000 ms / 100 ms) in the register for time overrun
(0x1000).
2.
Write 0x0010 (=2
(5-1)
) in the coding mask (register 0x1001) to start the
watchdog.
3.
Use the function ‘Force Single Coil’ to trigger the watchdog.
4.
Read the register of the minimum current trigger time and compare this
with zero to check whether a time overrun has occurred.
Repeat step 3 and 4.
•
Setting the watchdog for a time overrun of more than 10 min
1.
Write 0x1770 (=10*60*1000 ms / 100 ms) in the register for time over-
run (0x1000).
2.
Write 0x0001 in the watchdog trigger register (0x1003) to start the
watchdog.
3.
Write 0x0001, 0x0000, 0x0001... or a counter value in the watchdog
trigger register (0x1003) to trigger the watchdog.
4.
Read the register of the minimum current trigger time and compare it
with zero to check if a time overrun has occurred.
Repeat step 3 and 4.
6.2.13 Diagnostic
function
The following registers can be read to determine errors in the network node:
Register address 0x1020
Designation
LedErrCode
Access
Read
Description
Declaration of the Error code
Register address 0x1021
Designation
LedErrArg
Access
Read
Description
Declaration of the Error argument
