Appendix 4. Link Master Functions; A4.1 Link Active Scheduler (Las); A4.2 Link Master (Lm) - YOKOGAWA Admag TI Series User Manual

Appendix 4. Link Master Functions

A4.1 Link Active Scheduler (LAS)
A link active scheduler (LAS) is a device to perform the network control function for Fieldbus.
Fieldbus always needs one LAS on the link.
This product supports the following LAS functions.
PN transmission
1
function
PT transmission
2
function
CD transmission
3
function
Time
4 synchronization
function
Live list equalization
5
function
LAS transfer
6
function
A4.2 Link Master (LM)
Any devices having the function as LAS are called a link master (LM). Though there must be
always one LAS on the link, there can be multiple LM devices. (Figure A4.1)
When the LAS stops working, another LM device on the link starts functioning as the LAS.
LM
Node address: 0x14
LAS
SlotTime = 5
LM
Node address:
0x15
SlotTime = 5
Figure A4.1 LM Device and Basic Device
Identifies a fieldbus device newly connected to the bus.* PN (ProbeNode)
Passes a token to a device on the link.* PT (PassToken)
Starts up a scheduled transmission to a device on the link.
*CD (CompleData)
Periodically transmits the time information to the link. Also, returns the time
information in response to a request from a device.
Sends the live list information to the link master device on the link.
Function to transfer the right to be the LAS to another link master device.
LM Basic device
Node address: Node address:
0x16 0xF1
SlotTime = 5
<Appendix 4. Link Master Functions>
There are 3 LMs on this segment.
Basic device Basic device
Node address: Node address:
0xF2 0xF3
266
Basic device
Node address:
0xF4
FA0401.EPS
IM 01E21A02-03EN