Configuration of Instrumentation System
Section
1-2
31
Note 1
In the case of an analog output Field Terminal block, select the function block
according to the Unit model.
Note 2
In data exchange above, the Loop Control Unit handles analog I/O signals
not in engineering units but in percentage units. For example, the data 0000
to 0F0A (FF38 to 1068) Hex from the Analog Input Unit for input 4 to 20 mA
(3.2 to 20.8 mA) are converted to 0.00 to 100.00 (-5.00 to 105.00) % before
they are processed by the Loop Control Unit.
These percentage unit values are scaled to engineering units values by CX-
Process Monitor.
WARNING
When the Field Terminal block is used for analog I/O, the unit number set on
the Field Terminal block must match the unit number set on the Analog I/O
Unit front panel. Otherwise, input/output (read/write) operations will be
performed by mistake on the data of another Special I/O Unit (having the unit
number set on the field terminals).
(2) When exchanging data with a specified I/O memory address (on
CPU Unit Terminal block or the Expanded CPU Unit Terminal block)
When the Loop Control Unit exchanges analog data with a specified I/O
memory address, use the AI Terminal from CPU Unit and AO Terminal to
CPU Unit blocks on the CPU Unit Terminal block or the Expanded AI
Terminal from CPU Unit and Expanded AO Terminal to CPU Unit on the
Expanded CPU Unit Terminal block.
In this instance, the Loop Control Unit can exchange data with any type of
unit as long as the data is allocated to the I/O memory addresses indicated in
the following table. (For example, data on analog terminals allocated to the
CompoBus/D Area can also be exchanged.)
The following table shows I/O memory that can be specified on CPU Unit
Terminals or the Expanded AI Terminal from CPU Unit or Expanded AO
Terminal from CPU Unit in the Extended CPU Unit block:
Area type
I/O memory address of CS1
CPU Unit
Remarks
CIO (channel
I/O) Area
0000 to 6143 words
Including I/O Area,
CompoBus/D Area, Data Link
Area, and Special I/O Unit Area
(*1)
Work Area (W)
W000 to 511 words
Holding Area (H)
H000 to 511 words
Data Memory (D)
D00000 to 32767 (words)
Including Special I/O Unit Area
in Data Memory Area
Extended Data
Memory (E) bank
No.0
E0_00000 to E0_32767
The following CPU Unit Terminal function blocks or the Expanded CPU Unit
Terminal block are used:
Number of points
Function block
8 words
AI Terminal from CPU Unit (Block Model 453)
Input
64 words
Expanded AI Terminal from CPU Unit (Block Model 457)
8 words
AO Terminal to CPU Unit (Block Model 454)
Output
64 words
Expanded AO Terminal from CPU Unit (Block Model 458)