DATA COLLECTING DEVICE

PURPOSE:To attain surely data collection by a master unit by releasing a power source self holding circuit of a slave unit by command from the master unit that collects data from plural slave units. CONSTITUTION:A master unit 1 and slave units 21-2n are connected by signal lines 31-3n, and data inputted from each of slave units 21-2n are sent to the master unit 1, and data collection is made by the master unit 1. The master unit 1 and slave units 21-2n are fed by inserting power source plugs 4, 5, to power source. In each slave unit, the relay 11 of a power source self holding circuit 61 is excited by pushing the power source plug in and depressing a push- button switch 10, and a contact 9 is closed to self hold a power source circuit. When a CPU 16 is in the reset state, the output is L level and does not drive a power source releasing circuit 12, and a contact 13 is in on state. When the amster unit sends out a power source off command signal to slave units through signal lines 31-3n after completion of data collection in the master unit side, the CPU 16 outputs H level. A transistor 15 turnes on and energizes a relay 14 to open the contact 13 and releases power source holding of the slave unit.