GB280486A - Improvements relating to electrical remote control and signalling systems - Google Patents

Abstract

280,486. Siemens Bros. & Co., Ltd., and Humphries, H. E. June 8, 1926. Drawings to Specification. Selective distant control systems; tell-tale apparatus.-Relates to a system for controlling and supervising apparatus located at a plurality of remote stations connected across common control and signalling line wires. The system described is identical with that described in Specification 280,254, but the claims relate to the means for operating the supervisory signal lamps at the control station whereby when an apparatus unit at a substation changes its position either due to a control operation or automatically, a preliminary indication of the change is given and is changed manually by the operator into a final indication. When a unit changes its position, impulse trains characteristic of the sending substation and the unit are transmitted to the central station to operate step-bystep switches which effect the selection of the appropriate signal lamp. The signal lamp circuits of each apparatus unit are controlled by two differential relays and the arrangements are such that the incoming signal causes the appropriate lamp to flicker in order to signify that a change has taken place and indicate the nature of such change. The signal is acknowledged by the operation of a key at the control station to cause the steady illumination of the lamp. In a modification, an additional lamp, which is operated when a change takes place, is used instead of the flickering arrangement. The arrangement of relays meet the case where the condition of apparatus is signified by a final indication and the apparatus changes condition and then reverts to the former position so rapidly that only the signal of the former condition may be sent, in which case the final indication is changed to a preliminary indication in order that the change may be recorded. Specification 230,291, [Class 40 (iv), Telephones &c.], also is referred to.