Base Item Names
- Last UpdatedMay 21, 2020
- 2 minute read
This section describes the base item names and the conditions applicable to them:
-
Item names must begin with base name strings and optionally preceded by "%."
-
Item names are not case-sensitive.
The following table summarizes the base name, description, data type, read/write (R/W) designation, and offset for base item names.
|
Base Name |
Description |
Data Type |
Access Rights |
Offset |
|---|---|---|---|---|
|
In |
Discrete inputs |
VT_BOOL |
R/W |
n = 1-65535 |
|
On or Qn |
Discrete outputs |
VT_BOOL |
R/W |
n = 1-65535 |
|
Tn |
Discrete temporary |
VT_BOOL |
R/W |
n = 1-65535 |
|
Mn |
Discrete internal |
VT_BOOL |
R/W |
n = 1-65535 |
|
Gn |
Genius global data |
VT_BOOL |
R/W |
n = 1-65535 |
|
GAn |
Genius seamless A table* |
VT_BOOL |
R/W |
n = 1-64255 |
|
GBn |
Genius seamless B table* |
VT_BOOL |
R/W |
n = 1-62975 |
|
GCn |
Genius seamless C table* |
VT_BOOL |
R/W |
n = 1-61695 |
|
GDn |
Genius seamless D table* |
VT_BOOL |
R/W |
n = 1-60415 |
|
GEn |
Genius seamless E table* |
VT_BOOL |
R/W |
n = 1-59135 |
|
Wn |
PLC WORD register |
VT_UI2 or forced by suffix |
R/W |
n = 1-2147483647 |
|
Rn |
PLC register |
VT_UI2 or forced by suffix |
R/W |
n = 1-65535 |
|
Rn:b Similarly for data types %AI, %AO or %AQ, %P, BLOCKNAME^%L, %W |
PLC register bit |
VT_BOOL |
Read-Only (R/O) |
b = 0-15 |
|
Rn-Rm M Similarly for data types %AI, %AO or %AQ, %P, %W. For %L, the syntax is BLOCKNAME^%Ln-Lm M |
String contained in consecutive bytes in the PLC registers |
VT_BSTR |
R/W |
|
|
Rn-Rm A Similarly for data types %AI, %AO or %AQ, %P, %W. For %L, the syntax is BLOCKNAME^%Ln-Lm A |
String contained in consecutive PLC registers |
VT_BSTR |
R/W |
|
|
AIn |
Analog inputs |
VT_UI2 or forced by suffix |
R/W |
n = 1-65535 |
|
AOn or AQn |
Analog outputs |
VT_UI2 or forced by suffix |
R/W |
n = 1-65535 |
|
Sn |
System discretes |
VT_BOOL |
R/O |
n = 1-128 |
|
SAn |
System discretes |
VT_BOOL |
R/O |
n = 1-128 |
|
SBn |
System discretes |
VT_BOOL |
R/O |
n = 1-128 |
|
SCn |
System discretes |
VT_BOOL |
R/O |
n = 1-128 |
|
BLOCKNAME^ %Ln |
Sub-program block registers** |
VT_UI2 or forced by suffix |
R/W |
BLOCKNAME = corresponding block name in the control program of the PLC. n = 1-8192 |
|
%Pn |
Task memory of the PLC control program*** |
VT_UI2 or forced by suffix |
R/W |
n = 1-8192 |
|
%Wn |
Retentive Bulk Memory Area, which is referenced as %W (WORD memory). |
VT_UI2 or forced by suffix |
R/W |
n = 1- 2147483647 (which is a 4 byte address range/2). |
* Items GA, GB, GC, GD, and GE are supported only by the Series 90-70 PLCs.
** Item %L is supported for Series 90-70 PLCs and PACSystems RX3i/7i.
*** Items %P is supported only for Series 90-70 PLCs.
If the number of values written to a string item (for example, R1-R20 M or R1-R20 A) is greater than the number of elements in the string or if the item value is out of range, then the transaction is shown as Error with a description of Write Result as Error[The value is out of range.].