Modbus Watchdog - Pepperl+Fuchs AS-i Compact Manual

EtherNet/IP + Modbus TCP-Gateways
ModbusTCP
6.2.1

Modbus watchdog

The watchdog is set by default to 1000 msec (= 100 in register 61441). This value
will be automaticly set after POWER ON of the gateway. Every write access on
any Modbus registers reloads the watchdog timer. If no values are written before
the watchdog timer is counted to zero the gateway will automatically put all AS-i
circuits that are not in conguration mode in a safe state by clearing the outputs.
This means they are reseted.
The timeout period can be adjusted if necessary at the address 61441 (in 10 ms
units, range 1 ... 65536) but it will return to the default value on power cycle.
If zero is written to the address 61441, the watchdog is disabled.
The reference 2087 holds the default value for the watchdog timeout. This value
is set in the register 61441 after power on of the gateway. This period can be ad-
justed from 0 ... 999 (0 = watchdog disabled). Writing to this register also writes to
the register 61441.
Reading the address 61441 returns the watchdog holdup time remaining (reset to
value written at each output operation).
4 x reference 4226
bit value
1 (0x1)
2 (0x2)
4 (0x4)
Data_Exchange_Active: If this output is set, no data transmisson between the
Auto_Address_Enable: This output blocks automatic slave-address program-
host interface flags
Data_Exchange_Active
Off_Line
Auto_Address_Enable
gateway and the AS-i slaves is possible.
0: Data exchange is not active
1: Data exchange is active
Off-line: This output sets the master into the off-line phase.
0: on-line
1: off-line
ming.
0: Auto-address is disabled
1: Auto-address is enabled
Tab. 6-18. Reference 4226
27