Chapter 8 Logic Instructions 
8-207 
8.14.2.5  ETH_Link_Config_Ext 
FB/FC 
Explanation  Applicable model 
FB 
ETH_Link_Config_Ext is used to configure the cycle time and link 
duration for MODBUS TCP data exchange. 
 
  Input Parameters 
Parameter name  Function  Data type 
Validation timing 
Execute 
executed when Execute 
changes from FALSE to 
BOOL 
TRUE or FALSE 
(FALSE) 
 
CycleTime 
The cycle time the master 
sends MODBUS TCP 
data. 
ARRAY [1..16] 
OF UINT 
0~65535 
(0) 
When Execute 
changes from 
FALSE to TRUE. 
LinkKeeptime 
The link duration of the 
master (Unit: seconds) 
ARRAY [1..16] 
OF UINT 
0~65535 
(0) 
changes from 
Note: 
1.  Every element of the values in CycleTime  and  LinkKeeptime  corresponds to the number in a 
ETH_Link_Config instruction. For example, the first element of CycleTime value corresponds to the 
data-sending cycle time of the number 1. 
2.  The unit of CycleTime is milliseconds (ms) and LinkKeepTime is seconds (s). 
3.  LinkKeeptime is the link duration (unit:seconds). If there is no data exchange between the master and 
slave within the time specified by  LinkKeeptime,, the controller will disconnect the link to the slave 
automatically. 
  Output Parameters 
Function  Data type  Valid range 
TRUE when the instruction execution is completed. 
  Output Update Timing 
Timing for changing to TRUE  Timing for changing to FALSE 
Done 
 When Execute changes to 
 When Execute changes from TRUE to 
 
  Function 
When the MODBUS TCP master function of the controller is used, ETH_Link_Config_Ext can be used 
to set the cycle time and link duration for MODBUS TCP data exchange. The firmware of V1.01 and 
above supports the function. 
1.  The ETH_Link_Config_Ext instruction can be used to set the cycle time and link duration for MODBUS 
TCP data exchange. The instructon can also be used in the configuration of MODBUS TCP parameters. 
And it can still be used in the MODBUS TCP master function of the controller. One piece of MODBUS 
TCP data sending is finished and then another piece will be sent out immediately. The link duration is 
ETH_Link_Config_Ext
Execute
ETH_Link_Config_Ext_instance
CycleTime
Done
LinkKeeptime