Yokogawa EJA115 - Manual (Page 69)

IM 01C22T02-01E A-31
APPENDIX 5. Link Master Functions
Element Description
Sub-
index
Size
[bytes]
2
4
2
Indicates the version number of
the LAS schedule downloaded
to the corresponding domain.
Indicates the macro cycle of the
LAS schedule downloaded to
the corresponding domain.
Indicates the time resolution
that is required to execute the
LAS schedule downloaded to
the corresponding domain.
Version
Macrocycle
Duration
TimeResolution
1
2
3
TA0514.EPS
(15) Domain
Read/write: impossible; get-OD: possible
Carrying out the GenericDomainDownload command
from a host writes an LAS schedule to Domain.
A5.6 FAQs
Q1. When the LAS stops, an EJA does not back it
up by becoming the LAS. Why?
A1-1. Is that EJA 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:
EJA Other LMs
V(ST)
ϫV(TN)
< V(ST)
ϫV(TN)
Q2. How can I make an EJA become the LAS?
A2-1. Check that the version numbers of the active
schedules in the current LAS and the EJA are
the same by reading:
LinkScheduleListCharacteristicsRecord (index
374 for an EJA)
- ActiveScheduleVersion (subindex 3)
A2-2. Make the EJA 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 EJA.
Q3. On a segment where an EJA works as the
LAS, another device cannot be connected.
How come?
A3-1. Check the following bus parameters that
indicate the bus parameter as being the LAS for
the EJA and the capabilities of being the LAS
for the device that cannot be connected:
• V(ST), V(MID), V(MRD) of EJA:
ConfiguredLinkSettingsRecord (index 369)
• V(ST), V(MID), V(MRD) of problematic
device: DlmeBasicInfo
Then, confirm that the following conditions are
met:
EJA Problematic
Device
V(ST) > V(ST)
V(MID) > V(MID)
V(MRD) > V(MRD)
A3-2. Check the node address of the problematic
device is not included in the V(FUN)+V(NUN)
of the EJA.
Q4. “----” is kept shown on LCD.
The LAS does not exist or is not identified in the
fieldbus network, or the EJA is not able to establish
communication with the LAS.
A4-1. Check that the LAS is connected on the net-
work. When using the EJA as the LAS, follow
the steps described in section A5.3.
A4-2. Adjust the parameters of the LAS to that of the
EJA. Refer to section 5.2 for details.
LAS EJA
V(ST) > V(ST) 4 or above
V(MID) > V(MID) 4 or above
V(MRD) > V(MRD) 12 or above
A4-3. Check that the correct Node Address is used for
the EJA. Refer to section 5.2 for details.
Confirm that the Node Address of EJA should
be out of the parameters of the LAS of V (FUN)
ϳV (FUN)ϩV (NUN)
Confirm that the Node Address is not within the
default address (0xF8 to 0xFB).