Two types of tokens are used by the LAS. The LAS sends a time-critical token,
compel data (CD) according to a schedule. The LAS also sends a non-time critical
token, pass token (PT) to each device in ascending numerical order according to
address.
8.2.2 Device addressing
Fieldbus uses addresses between 0 and 255.
Addresses 0 through 15 are reserved for group addressing and for use by the
data link layer. For all Emerson Fieldbus devices, addresses 20 through 35 are
available to the device. If there are two or more devices with the same address,
the first device to start uses its programmed address. Each of the other devices is
given one of four temporary addresses between 248 and 251. If a temporary
address is not available, the device is unavailable until a temporary address
becomes available.
8.3 Rosemount OCX8800 function blocks
8.3.1 Implemented function blocks
Table 8-1 shows the Rosemount OCX8800 implemented function blocks.
Table 8-1: Rosemount OCX8800 Implemented Function Blocks
Function block Description
Resource block
Transducer block
Analog input block 1 (AI1) See TB Channel Assignment, Table 8-18
Analog input block 2 (AI2) See TB Channel Assignment, Table 8-18
Analog input block 3 (AI3) See TB Channel Assignment, Table 8-18
Analog input block 4 (AI4) See TB Channel Assignment, Table 8-18
PID block (PID) Proportional/integral/derivative of any AI
block
Arithmetic block (ARTHM) Arithmetic function block
Input selector block (ISEL) Input selector function block
Manual FOUNDATION
™
Fieldbus
00809-0500-4880 December 2022
Rosemount OCX8800A 119
To Next Page
Loading...
