An HMI renders on an HMI screen a process line which includes: a movable looper group part obtained by grouping at least one movable roll part and a plurality of line parts connected to the movable roll part; and a plurality of fixed roll parts connected to the movable looper group part. The HMI continuously obtains a process line length from an output signal of a monitoring target device. The HMI calculates a looper movement amount by dividing a difference between a process line total length and the process line length by the number of parts in the plurality of line parts which are shared by the movable looper group part with the plurality of fixed roll parts. The HMI changes a relative position between the plurality of fixed roll parts and the movable looper group part on the HMI screen according to the looper movement amount.

An HMI renders on an HMI screen a process line which includes: a movable looper group part obtained by grouping at least one movable roll part and a plurality of line parts connected to the movable roll part; and a plurality of fixed roll parts connected to the movable looper group part. The HMI continuously obtains a process line length from an output signal of a monitoring target device. The HMI calculates a looper movement amount by dividing a difference between a process line total length and the process line length by the number of parts in the plurality of line parts which are shared by the movable looper group part with the plurality of fixed roll parts. The HMI changes a relative position between the plurality of fixed roll parts and the movable looper group part on the HMI screen according to the looper movement amount.

A communication system includes a communication device functioning as a master device and a plurality of slave devices communicably connected to the communication device via a communication line, the communication device setting a prescribed address in an added slave device based on a position of the added slave device in a topology composed of a plurality of slave devices, judging whether a change has possibly occurred in the topology when the prescribed address is set in the added slave device, if there is an erroneously set slave device whose address was erroneously set, specifying that slave device, when it is judged that a change has possibly occurred, and resetting the address of the specified erroneously set slave device to an original address.

A communication system includes a communication device functioning as a master device and a plurality of slave devices communicably connected to the communication device via a communication line, the communication device setting a prescribed address in an added slave device based on a position of the added slave device in a topology composed of a plurality of slave devices, judging whether a change has possibly occurred in the topology when the prescribed address is set in the added slave device, if there is an erroneously set slave device whose address was erroneously set, specifying that slave device, when it is judged that a change has possibly occurred, and resetting the address of the specified erroneously set slave device to an original address.