The module of IBS100 can be constructed to report the PLC operating status to the host of Interbus-S. This status can be sent in 2 forms. Both choices are allowed by default and possibly autonomously disabled.
1. The module can be constructed to replicate the present PLC operating status in the most important bit of the initial process data word. Visibly, if this choice is configured, the MSb of the initial data word process cannot be used to send data from the PLC to the controller host.
2. The module can be constructed to create a module error when a RUN to STOP conversion is detected.
Note: if the PLC is constructed for mode of “STOP DO I/O”, the module will report the PLC operating status as at all times running.
If the powers up of PLC in STOP mode, the width bits of Interbus-S data and the IBS Enable bit will not be sent from the PLC to the module of IBS100. The module of IBS100 will start itself to send either 0 or 1 data word of process. The data width constructed will base on whether the PLC operating status is sent in the initial process data word. If the initial process data word is utilized to report PLC operating status, the module will constructed the data width process to 1 word. If this channel is not utilized to report PLC operating status, the module will constructed the data width to 0 words.
The application programmer of host controller has to ensure that, subsequent the Interbus-S ID cycle, the appropriate process data width has been constructed for the module of IBS100. Guess that the correct process data width for the module is larger than 1 word, the application can presume that the PLC is in stop mode subsequent power-up if the Interbus-S ID cycle specifies that the module of IBS100 is constructed for process data words of 0 or 1.