Alspa CE80–20 FIP Bus Interface Unit User's Manual

Operation4. READY MODEThe Bus Interface Unit goes to Ready mode when a system-level configuration has been received and enabled.IdleReadyRunIn Ready mode: the Bus Interface Unit waits for permission to enter Run mode from the FIPnetwork controller, a Hand–Held Programmer can be used to monitor I/O and module configurations,and to force I/O data, configuration can NOT be changed by a Hand–Held Programmer, the Bus Interface Unit scans I/O in accordance with the configuration it receivedfrom the FIP network. If it was previously in Idle Mode, forced conditionspreviously stored in FLASH memory are restored and applied.Input data is representative of the values scanned from the I/O modules except ifthey have been defaulted or forced.Outputs are off or set to 0 if the FIP BIU was previously in Idle Mode or in a RunMode before receiving a Stop Cmd message from the network.Outputs are frozen if the FIP BIU was previously in a Run Mode and output datahas never been received from the network.Outputs are defaulted according to the configuration (default values or frozen) ifthe output data has been received at least once when in a Run Mode, before anetwork loss occured,the Bus Interface Unit accepts forcing information from the network.The Bus Interface Unit can be commanded (from the network) to go to Idle mode for reconfiguration or it maybe commanded to go to Run mode.Page 3–4Alspa CE80–20 FIP Bus Interface Unit User’s ManualALS 52311 b–en