Variables
The Omron driver supports the following Omron PLC registers as device variables for the Omron NJ or NX PLC:
| Variable | Description |
|---|---|
| Global Variable Tags | The Omron driver can access Controller tags defined in the global variable area of the system. |
| Members of User Defined Structures | The Omron driver can access members of user defined structures. |
| User Defined Strings | The Omron driver can access user defined strings. |
User defined strings on the Omron NJ or NX are terminated with a null (0x00) byte. The impact to the user is the writable area of a user defined string equals the defined length of the user defined string - 1. For example, the default string length on an Omron NJ or NX is 256 characters. One character is reserved for the null byte. The maximum number of characters that can be written to a string variable that uses the default string length of 256 characters would be 255 characters. The largest length that can be defined for a user defined string is 1986 characters, so a user defined string with this length would have a writable area of 1985 characters.
Data types, data conversion and addressing
The Omron driver and the runtime support the Omron NJ or NX PLC data types as follows:
| Omron data type | Runtime data type |
|---|---|
| SINT | INT1 |
| USINT | UINT1 |
| INT | INT2 |
| UINT | UINT2 |
| DINT | INT4 |
| UDINT | UINT4 |
| LINT | INT8 |
| ULINT | UINT8 |
| REAL | FLOAT4 |
| LREAL | FLOAT8 |
| BOOL | BOOL |
| STRING | STRING |
| TIME | TIMESTAMP |
The Omron NJ or NX PLC data types are supported in the the runtime environment wherever a variable is accessed and the variable is associated with a Omron 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 Omron NJ or NX PLC, the runtime and the Workbench are supported by the necessary data conversion functions (e.g. Real and Float4).