摘要 |
An alarm system comprises at least one trip unit 1 and a central unit 2. The central unit is self-programmable from the respective trip unit by being temporarily placed in programming mode P2. A coded output signal emitted by the trip unit is inputted into the CPU 24 of the central unit for storage in an EEPROM 25 connected thereto. In the normal operating mode N2 of the central unit, a coded output signal received from any one trip unit is compared with all the codes previously stored by self-programming in the EEPROM. If agreement is then found between a received coded output signal and any stored code, then the CPU relays the coded output signal as an alarm signal L. <IMAGE> |