Variables
ControlLogix and CompactLogix CPUs
The Rockwell driver supports the following Rockwell ControlLogix and CompactLogix PLC tags as device variables:
| Variable | Description |
|---|---|
| Controller Tags | The Rockwell driver can access Controller tags defined in the system. |
| Program Tags | The Rockwell driver can access Program tags defined in the system. |
| Alias Tags | The Rockwell driver can access Alias tags defined in the system. |
| User Defined Type (UDT) Tags | The Rockwell driver can access the data for an entire UDT tag from within the Set, Demand Read, and Demand Write trigger actions. The data returned will be in a BINARY format. UDT tags cannot be read from or written to in the Workbench Variables panel. |
| Members of User Defined Types | The Rockwell driver can access members of user defined structures. |
| User Defined Strings | The Rockwell driver can access user defined strings. |
| System Structures (Counter, Timer, etc) | The Rockwell driver can read system structures. It can write to system structures where the security access level allows for the writing of structure members. |
PLC-5 / SLC 500 / MicroLogix CPUs
The Rockwell driver supports the following Rockwell PLC-5, SLC 500, and MicroLogix PLC tags as device variables:
| Variable | Description |
|---|---|
| Global Tags | The Rockwell driver can access any global tags defined in the system. |
| Input / Output Tags | The Rockwell driver has read access to both Input and Output tags. Write access is available on Output tags. |
| System (S) | The Rockwell driver has read only access to these tags. |
| User Defined Strings | The Rockwell driver can access user defined strings. |
| System Structures (Counters and Timers) | The Rockwell driver can read system structures. It can write to the .ACC and .PRE elements within Counters and Timers. |
Data types and data conversion
The Rockwell driver supports the Rockwell PLC data types and their mapping to runtime data types as follows:
| Rockwell data type | Runtime data type |
|---|---|
| SINT | INT1 |
| INT | INT2 |
| DINT | INT4 |
| LINT | INT8 |
| REAL | FLOAT4 |
| BOOL | BOOL |
| STRING | STRING |
| UDT Runtime Data | BINARY |
| DT | TIMESTAMP |
| LDT | TIMESTAMP |
| TIME | UINT8 |
| LTIME | UINT8 |
Micro800 CPUs
The Rockwell driver supports the following Rockwell Micro800 PLC tags as device variables:
| Variable | Description |
|---|---|
| Global Tags | The Rockwell driver can access any global tags defined in the system. |
| Input / Output Tags | The Rockwell driver has read access to both Input and Output tags. Write access is available on Output tags. |
| Arrays | The Rockwell driver can access 1, 2, and 3 dimension arrays. Elements may be any scalar type, string, or UDT. |
| Structures and User Defined Type (UDT) Tags | The Rockwell driver can access members of user defined structures. Accessing data for an entire UDT tag as a BINARY data type is not supported. |
Micro800 data types and data conversion
The Rockwell driver Micro800 CPU device supports the Rockwell PLC data types and their mapping to runtime data types as follows:
| Rockwell data type | Runtime data type |
|---|---|
| SINT | INT1 |
| INT | INT2 |
| DINT | INT4 |
| LINT | INT8 |
| USINT, BYTE | UINT1 |
| UINT, WORD | UINT2 |
| UDINT, DWORD, DATE, TIME | UINT4 |
| ULINT, LWORD | UINT8 |
| REAL | FLOAT4 |
| LREAL | FLOAT8 |
| BOOL | BOOL |
| STRING | STRING |
Runtime Support
The Rockwell PLC data types are supported in the runtime environment wherever a variable is accessed and the variable is associated with a Rockwell PLC device. Some examples are:
- Workbench Variables window Read as and Write as functions
- Transport map data type parameters
- Trigger data type parameters
- Trigger action variable data type parameters.
The data representations in the Rockwell PLC, the runtime and the Workbench are supported by the necessary data conversion functions (e.g. Real and Float4).