A CB3 controller running standard PolyScope can use variables from the active installation, but the available evidence does not identify a script command that reads a variable directly from another installation file. Treat direct cross-installation access as unsupported unless Universal Robots documentation or testing confirms otherwise.
Separate Installation Variable Scope
Installation variables belong to the current installation context. Changing which installation is active therefore changes the variable set available to the program; a variable in another installation file is not established as directly addressable from script.
| Requirement | Supported conclusion |
|---|---|
| Use a variable from the active installation | Available to programs using that installation. |
| Read a variable from another installation file | No supporting script command is identified. |
| Share a value across installations | Requires a separate persistence mechanism; a custom URCap that saves values to a file is the proposed approach. |
Select the Appropriate Design
If multiple programs need the same value, place them under the same installation when that fits the cell design. If the programs must retain separate installations, do not make their operation depend on direct access to one another’s installation variables.
Implement and Verify External Persistence
For separate installations, use a custom URCap or another validated mechanism to save the shared value outside the installation-variable scope. The evidence proposes file storage through a URCap but does not define a file format, API, path, synchronization behavior, or failure handling; establish those details during implementation.
- Write the shared value through the persistence mechanism while the source installation is active.
- Load the other installation and read the stored value through the same mechanism.
- Change the source value, repeat the installation change, and confirm that the destination receives the updated value.
- Test missing, invalid, and stale stored data before allowing the value to control robot behavior.
FAQ
Can PolyScope read a variable from another installation file?
The evidence identifies no script command for direct cross-installation variable access. Variables from the active installation are available, but variables in another installation should be treated as inaccessible until officially confirmed otherwise.
How can I share a CB3 variable between installation files?
Use a separate persistence mechanism. The proposed solution is a custom URCap that saves the value to a file and retrieves it when the other installation is active.
Should multiple CB3 programs use the same installation?
If they require the same installation variables and can share the same installation configuration, using one installation avoids cross-file transfer. Otherwise, implement and test external persistence.
