Mitsubishi Electric MELSEC iQ-RJ71EN71 User Manual page 69

Program that detects loopback station numbers (master operating station only)
By detecting loopback station numbers, a faulty station can be found. Whether loopback is being performed or not can be
checked using 'Network topology setting' (SB0078) and 'Loopback status' (SB0065) of the master operating station.
Ex.
Program that stores loopback station numbers to 'wLoopbackStationNumber_1' (D1000) and 'wLoopbackStationNumber_2'
(D1001)
Classification Label name
Module label GF11_1.bSts_DataLinkError
GF11_1.bOpe_Loopback
GF11_1.bSet_RingTopology
GF11_1.wnVal_LoopbackStationNumber[1]
GF11_1.wnVal_LoopbackStationNumber[2]
Label to be defined Define global labels as shown below:
(3) When 'Network topology setting' (SB0078) and 'Loopback status' (SB0065) are on, 'Loopback station number 1' (SW0070) and 'Loopback station number 2'
(SW0071) are saved.
Precautions
■Support for the loopback function
To use the loopback function, check whether the master/local module on the master station supports the loopback function. To
check the support for the loopback function, refer to the following.
 User's manual for the master/local module used
■Loopback function setting and network configuration
To use the loopback function, configure the network in ring topology and set "Network Topology" to "Ring" in "Basic Settings"
of the master station. If "Network Topology" and the network configuration are inconsistent, an error may occur in all stations
and data link cannot be performed.
Description
Data link error status of own station
Loopback status
Network topology setting
Loopback station number 1
Loopback station number 2
Device
SB0049
SB0065
SB0078
SW0070
SW0071
1 FUNCTIONS
67
1.5 Loopback Function
1