User Manual Section 4
GFK-2958L May 2021
Detailed Descriptions of the Fieldbus Network Adapters 110
If 0xFFFF is read, the watchdog is deactivated.
4.4.17 0x1120 MODBUS DATA EXCHANGE watchdog,
predefined time
In this register, the watchdog is activated/deactivated, and the watchdog time is set.
Process date can be exchanged as long as the watchdog is deactivated, or it is activated and
still running. But it is accepted only after a watchdog reset to the current time. The length is
calculated with the input value * 10ms. Entering 0 deactivates the watchdog.
4.4.18 0x1121 MODBUS DATA EXCHANGE Watchdog Reset
Register
If Bit 0 in this register is set, the predefined time is loaded into the watchdog time (watchdog
reset).
If Bit 8 in this register is set, an expired watchdog (value 0 in register 1030) is reactivated.
4.4.19 0x1122 Lock Force Mode on Web Server
In default setting the force mode can be enabled via the web server (after Login). The force
mode can be locked by writing the double word ”LOCK“ (0x4C4F, 0x434B). Writing of
”FREE“ (0x4652, 0x4545) will unlock the force mode again.
4.4.20 0x1031 MODBUS CONNECTION Mode Register
MB_ImmediateWritePermission
– 0: during the first write access, write authorization is requested for the corresponding Modbus connection.
If this is not successful, an exception response with the exception code 0x01 is generated. If it is successful,
the write access is executed and write authorization remains in effect until the end of the connection.
– 1: write authorization for the corresponding Modbus connection is already requested when the connection
is being established. As a result, the first Modbus connection receives the write authorization, and nothing
happens for all those that follow (as long as Bit 0 = 1).
MB_OnlyOneWritePermission
– 0: all Modbus connections have written authorization
– 1: in all cases only one Modbus connection can be assigned write authorization. Once assigned, write
authorization is retained until there is a disconnect. After the connection that has write authorization is
disconnected, the next connection which attempts write access receives write authorization.