Removing a master – Rockwell Automation 2708-DH5B2L_DH5B4L Attended Workstation User Manual
Page 66
Chapter 6
Operating Procedures
6–3
If the Master is physically removed from the network, fails to function, or the
Host stops communicating, then a Master is considered removed from the
network. No data can be received by the Host until the problem is remedied.
If the problem is that the Host has stopped communication, there is a
possibility that the problem lies with the Host. If that is indeed the case, the
solution of the problem is also with the Host, and should be addressed there.
In some cases, the Host will stop communicating due to a problem with the
Master, even though to outward appearances, the Master is fine. Substitution
of another workstation to act as Master will usually show whether the
problem is with the Master Workstation or the Host. See the section on
Instituting a New Workstation as Master.
Alternate Master in Place – If an Alternate Master has already been selected
and established as an Alternate Master on the network, then it will begin
operation at any time from 90 to 120 seconds after the original designated
Master became inoperable.
When the alternate Master begins operating as the new Master, it will briefly
display:
cc–nn
READY
ONLINE
[M]
where cc is the Master number if this workstation is a Submaster, and nn is
the workstation ID.
Notice that all of the workstations attached to this Master (or Submaster) will
change their Concentrator or Master number to correspond to the new
configuration.
Host/Alternate Master – The Host computer must be ready to accept data
from the Alternate Master or else the workstations on the network will
continue to accept transactions only until their memory is filled. They will
then stop functioning.
No Alternate Available – If no alternate Master is available to take over the
role of Master, then the group of workstations attached to the offline Master
will also go offline after about a minute. When that occurs, each of the
workstations will display:
nn
READY
OFFLINE
Removing a Master