Matsushita Electric Industrial Co., Ltd.

Matsushita Electrical Industrial Co., Ltd.

Yoshifumi Hara

Saburo Kubota

Tutomu Sakurai

Satoshi Tanaka

Tsutomu Sakurai

Yasumasa Dougakiuchi

A fault examining apparatus is provided in a loop network system, in which a master station is connected sequentially with a plurality of follower stations in a loop transmission path to transfer digital optical signals denoting serial data information from the master station to the follower stations, from the follower stations to the follower stations or from the follower stations to the master station. The apparatus includes a device for detecting and storing a present value, a maximum value and a minimum value of a peak level value of received optical signals, and a display device for displaying the values.

Fault examining apparatus for loop-shaped data transmission system using

When an input data of a slave station makes any change, the slave station transmit a serial information (in serial data frame, FIG. 2) which is made by altering an information continuously transmitted from a master station into a serial information to be transmitted by interrupt, which serial information includes a start information (in start bit), interrupt information (in interrupt field), address information (in address field) of this slave station and data information (in data field) produced in this sub-station responding the change, and it is transmitted by the interrupt; therefore the master station can find the interrupt-transmitted serial information among many serial informations sent back thereto, and the slave station can immediately transmit the change to the master station without wasting time by waiting for one turn scanning of all the slave stations.

Data transmission apparatus

In a loop-type optical fiber transmission system composed of a master apparatus (50) and a plurality of slave apparatus (54), when an intensity of incident light (6B, 6C, 6E) to a first slave apparatus (55) is insufficient, the first slave apparatus (55) sends a status signal (CS.sub.b) informing malfunction in the light intensity to the master apparatus (50), the master apparatus upon receipt of the status signal from the first slave apparatus (55) sends a command signal to increase an output light intensity of a second slave apparatus (54) which is positioned at the upper stream of the first slave apparatus (55), and thus the intensity of the output light from the second slave apparatus (54) is increased.

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Hirakata, Japan

Yoshifumi Hara