Yokogawa EJX930A - Manual (Page 142)

<Appendix 6. Link Master Functions>
A6-8
IM 01C25R03-01E
(12) LinkScheduleActivationVariable
Writing the version number of an LAS schedule,
which has already been downloaded to the domain,
to this parameter causes the corresponding
schedule to be executed. On the other hand,
writing 0 to this parameter stops execution of the
active schedule.
(13) LinkScheduleListCharacteristicsRecord
Sub-
index
Element
Size
[bytes]
Description
1 NumOf
Schedules
1 Indicates the total number
of LAS schedules that have
been downloaded to the
domain.
2 NumOfSub
SchedulesPer
Schedule
1 Indicates the maximum
number of sub-schedules an
LAS schedule can contain.
(This is fixed to 1 in the
Yokogawa communication
stacks.)
3 ActiveSchedule
Version
2 Indicates the version number
of the schedule currently
executed.
4 ActiveSchedule
OdIndex
2 Indicates the index number
of the domain that stores the
schedule currently executed.
5 ActiveSchedule
StaringTime
6 Indicates the time when
the current schedule began
being executed.
(14) DlmeScheduleDescriptor
This parameter exists for the same number as the
total number of domains, and each describes the
LAS schedule downloaded to the corresponding
domain. For the domain to which a schedule
has not yet been downloaded, the values in this
parameter are all zeros.
Sub-
index
Element
Size
[bytes]
Description
1 Version 2 Indicates the version
number of the LAS
schedule downloaded to the
corresponding domain.
2 Macrocycle
Duration
4 Indicates the macro cycle
of the LAS schedule
downloaded to the
corresponding domain.
3 TimeResolution 2 Indicates the time
resolution that is required
to execute the LAS
schedule downloaded to the
corresponding domain.
(15) Domain
Read/write: impossible; get-OD: possible
Carrying out the GenericDomainDownload
command from a host writes an LAS schedule to
Domain.
CAUTION
When downloading a LAS schedule to EJX,
maximum allowable linkages between devices
are 18.
A6.6 FAQs
Q1. When the LAS stops, an EJX does not back
it up by becoming the LAS. Why?
A1-1. Is that EJX running as an LM? Check that
the value of BootOperatFunctionalClass
(index 367) is 2 (indicating that it is an LM).
A1-2. Check the values of V(ST) and V(TN) in all
LMs on the segment and confirm that the
following condition is met:
EJX Other LMs
V(ST)×V(TN) < V(ST)×V(TN)
Q2. How can I make an EJX become the LAS?
A2-1. Check that the version numbers of the active
schedules in the current LAS and the EJX
are the same by reading:
LinkScheduleListCharacteristicsRecord
(index 374 for an EJX)
- ActiveScheduleVersion (subindex 3)
A2-2. Make the EJX declare itself as and become
the LAS by writing:
• 0x00 (false) to
PrimaryLinkMasterFlagVariable in the
current LAS; and
• 0xFF (true) to
PrimaryLinkMasterFlagVariable (index 364)
in the EJX.