Omron CS1W-CLK12-V1, Operation Manual

Page: 122 / 312

105
Checking Data Link Status Section 5-4
The flags in the data link status operate as follows:
The Data Link Participation Flag and the PLC Status Flag can be used to see
if the system has started normally. These flags, however, cannot be used to
detect communications errors. Use the Communications Error Flag and PLC’s
CPU Unit Error Flag to detect errors.
If the Local Node Data Link Participation Flag is OFF, the previous status will
be maintained as the data link status and may not be correct. Make sure that
the Local Node Data Link Participation Flag is ON before checking data link
status.
Note The following Local Node Data Link Participation Flags are available.
CS-series, CVM1, CV-series PLCs:
Bit 15 in 1500 + 25 x unit 6
The data link status is enabled only when the local node is participating nor-
mally in the network. Make sure that the Local Node Data Link Participation
Flag is ON before checking data link status.
The data link status storage area is set as follows:
Name Function
Data link
participation The corresponding flag will turn ON if the node has never partici-
pated in the data link normally. The flag will not turn OFF once it
has turned ON even if the node is no longer participating in the
data links.
Communications
error The corresponding flag will turn ON if continuous data link data
cannot be received from the node, e.g., due to a cable break.
The flag will turn OFF again if data is received from the node nor-
mally.
The local node’s Communications Error Flag will be ON if the
local node is isolated from the network.
PLC’s CPU Unit
error The corresponding flag will turn ON if the CPU Unit has a fatal
error, non-fatal error, or watchdog timer error. The flag will turn
OFF again if the node returns to normal.
The status of this flag is based on data sent from the node and
will not turn ON if data cannot received, e.g., due to a Communi-
cations Error. Make sure that the Communications Error Flag is
OFF before checking this flag.
PLC status The corresponding flag will turn ON if the user program is being
executed in the CPU Unit. It will turn OFF is the user program is
not being executed.
The status of this flag is based on data sent from the node and
will not turn ON if data cannot received, e.g., due to a Communi-
cations Error. Make sure that the Communications Error Flag is
OFF before checking this flag.
0 0 0 0
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
1: Local node participating in data link.
0: Local node not participating in data link or data link stopped.
0 0 0 0 0 0 0 0 0 0 0
Data link
mode
PLC and
operating level
First data link
status word
Setting range Default status
Automatic CS-series PLC Specify in
DM 30000 + 100
×
N + 7
16 or 31 words between
CIO 000 and 6640 CIO 1500 + 25
×
N + 7 to 22
CVM1 or CV-
series PLC Specify in DM 2000
+ 100
×
N + 7
16 or 31 words between
CIO 000 and 2540 CIO 1500 + 25
×
N + 7 to 22