Checking The Status Of An Ethernet Global Data Exchange - GE VersaMax PLC User Manual

266 GFK-1503E
For public disclosure
The Ethernet interface updates these status bits every PLC I/O scan. The Ethernet status
bits normally occupy a single block of memory. Most of these bits are reserved. Five are
of interest for checking the status of the Ethernet interface:
Status Bits
Reserved, always 0
1–2
Full-duplex
3
Reserved, always 0
4–12
13 LAN OK
Resource problem
14
Reserved, always 0
15
16 LAN Interface OK
17-80 Reserved
If this bit 3 is 1, CPUE05 is operating in full-duplex Ethernet
mode. Full-duplex or half-duplex operation is automatically
Bit 3: negotiated between the CPUE05 and its
Full Duplex immediately-connected network device, usually a network
hub. If this bit is 0, CPUE05 is operating in half-duplex
Ethernet mode. This bit is only valid if bit 13 (LAN OK) is 1.
This bit is 1 while the Ethernet interface is able to
communicate on the network. If the network is not accessible
Bit 13:
due to local or network problems, this bit is 0. When
LAN OK
communication resumes, it is automatically set to 1.
This bit is 1 whenever the Ethernet interface has a resource
problem (i.e., lack of data memory). The bit is reset to 0 on a
subsequent PLC sweep. The Ethernet interface may or may
Bit 14:
not be able to continue functioning, depending on the severity
Resource Problem
of the problem. Use the PLC Fault Table to identify the
problem. The Station Manager STAT B and LOG commands
can also provide more information.
When this bit is 1, the Ethernet interface is properly
Bit 16:
initialized. When this bit is 0, all other Ethernet status bits are
LAN Interface OK
invalid.
13.5.5 Checking the Status of an Ethernet Global
Data Exchange
To check the status of any Ethernet Global Data exchange, monitor the value in the
Exchange Status word (selected during Ethernet Global Data configuration). The PLC
automatically writes exchange status information in this location when:
• a producer/consumer period expires ( the value is set for the entire period)
• an Ethernet Global Data configuration is stored to the PLC
• the PLC powers up and it has an Ethernet Global Data configuration
• the Ethernet interface configured for Ethernet Global Data is restarted
Brief Description
VersaMax PLC User Manual