can not send any command to dual system safegurad from workplace
The operations you listed (block, change limits) need Tune permission in Advant Master so please verify that the operator holds Tune. You can also try from an administrator account.
The SafeGuard has a function called DualHandler which runs on the RTA. The DualHandler must be properly setup for each pair of SafeGuard controllers on the MB300 control network.
Please consult the SafeGuard documentation or ServiceDesk in Oslo, Norway (support contract may be required).