EP 0287991 B1 19910918 - CIRCUIT ARRANGEMENT FOR THE AUTOMATIC FUNCTION-CHECKING OF A MONITORING DEVICE
Title (en)
CIRCUIT ARRANGEMENT FOR THE AUTOMATIC FUNCTION-CHECKING OF A MONITORING DEVICE
Publication
Application
Priority
DE 3713392 A 19870421
Abstract (en)
[origin: EP0287991A1] The arrangement is for optical signal systems with a test system (PRS) which simulates faults by appropriately influencing (BE) the monitoring unit (UWE). An alarm (ALA) thereby triggered is suppressed during the period of the test. The circuit arrangement consists of a fail-safe exclusive OR circuit (EXOR) which has a locking (Kl) alarm relay (K) and two pump circuits (A and B) each with an associated capacitor (C3, C4), and an RC element (RI, Cl and R14, C2) fitted in the input circuit and switching transistors (Tl to T6). The pump circuits (A, B) generate the excitation voltage for the alarm relay (K). The first pump circuit (A) receives the alarm signal (ALA) and the second pump circuit (B) receives the alarm suppression signal (ALU). In each case, one pump circuit (A or B) charges its capacitor (C3 or C4) whilst the other pump circuit (B or A) discharges its capacitor (C4 or C3) via the alarm relay (K), the alarm relay (K) dropping out when the negative capacitor voltage goes below the drop-out voltage. <IMAGE>
IPC 1-7
IPC 8 full level
G08G 1/097 (2006.01)
CPC (source: EP)
G08G 1/097 (2013.01)
Designated contracting state (EPC)
AT CH DE FR GB IT LI NL
DOCDB simple family (publication)
EP 0287991 A1 19881026; EP 0287991 B1 19910918; AT E67621 T1 19911015; DE 3864884 D1 19911024
DOCDB simple family (application)
EP 88106147 A 19880418; AT 88106147 T 19880418; DE 3864884 T 19880418