334,846. Reyrolle & Co., Ltd., A., Leeson, B. H., Anderson, W., and Lambert, D. E. June 1, 1929. Divided on 334,263. Selective distant control and signalling. - In an electric selective remote indicating and metering system in which two selectors are provided, one at a control station and the other at a substation, corresponding step-by-step movements are imparted to the selectors to obtain selective indications of the condition of the substation apparatus, and means are provided whereby the movements of the selectors may be arrested in half-way or " halfnotch " positions in which positions metering circuits can be established to indicate meter readings at the control station. The control station may be provided with a group of selfrecording meters and with apparatus for initiating automatically at predetermined intervals a complete selecting and metering cycle whereby the records on all the meters are periodically corrected. The invention is described in association with selector control arrangements forming the subject-matter of the invention described in Specification 334,263 and which are described in the abridgement of that Specification. Remote control system, Fig. 6. In this arrangement the control station and substation are connected by four pilot wires' p - - P . The control station is provided with a rotary selector 300 driven from a drum 30 which performs a series of sequential angular movements under the control of an electromagnetically operated escapement mechanism employing a coil 311. The substation apparatus comprises a rotary selector 100 driven from a drum 110 controlled by an escapement coil 111. Selection of substation apparatus is effected by depressing a push 350 which closes a contact 351 to complete a circuit for the escapement coil 311 whereby the selector 300 is actuated. The arrangement is such that the selector 300 in moving from one selected position to the next makes a first halfnotch movement, then the selector 100 makes two separate half-notch movements and finally the selector 300 makes its second half-notch movement. In the new selected position a supervisory indication circuit is completed over pilot wires p , P whereby indicating mechanism which may be as described in one or other of Specifications 307,381, 307,383, and 334,264 is operated. Metering circuits can be established in the half-notch positions of the selectors, the arrangement being that depression of the meter switch 410 having contacts 411 to 415, closes contact 413 to complete a circuit for coil 353 whereby the selector push is electromagnetically operated. A selecting movement then takes place which is arrested at the half-notch position due to a circuit being opened at contacts 414. Contact 415 closes to energize a locking coil 381 of the selected meter and release the meter pointer, the meter being preferably of the selfrecording kind as described in Specification 317,422. Contact 412 closes to prepare the metering circuit at the control station end. At the substation the drum contacts 121 are closed in the half-notch position whereby the relay 250 is energized to open the indicating circuit at contact 253 and close the metering circuit at contacts 251, 252. The metering circuit includes the metering source 200, the pilot wires P , P , and the meter 380. Release of the meter switch allows the selectors to complete their second halfnotch movements. Means are provided for establishing telephonic communication between the control station and the substation and for transmitting to the control station general alarm currents when a change takes place automatically in the condition of the substation apparatus. If the change occurs when the selectors are in the normal zero position the coil 353 is energized to depress and twist the push 350, whereby an express selecting cycle through all positions of the switches takes place so that the indicating mechanism can show the condition of the substation apparatus. Remote control system, Fig. 7. Two wires P , P and an earth return are employed and the system does not perform executive functions on substation apparatus as in the system shown in Fig. 6. The control station selector 600 is driven by a drum 620 controlled by an escapement coil 629, the substation selector 500 being similarly driven by a drum 520 controlled by an escapement coil 526. The control of the selectors is such that the first half-notch movement of the selector 600 takes place before the first half-notch movement of the selector 500, but the second half-notch movements take place simultaneously. Selection is effected by depression of a push 635. This push is electromagnetically operated by means of a coil 638 when the meter switch 670 is operated, so that a selecting movement is initiated, this movement stopping at the end of the first half-notch movement of the substation selector. A metering circuit is established through a metering source such as 515, pilot wire P , meter 610, and earth return. Release of the meter switch causes completion of a selecting movement. For telephonic communication the substation apparatus 570 includes, in addition to the telephonic instrument, a tuned buzzer and a tuned vibrator and is controlled by a four-way plug 571 adapted to connect the vibrator through condensers 574, 575 to pilot wires P , P , and to cause a relay 580 to be energized, whereby the wires are disconnected from the substation remote control apparatus. At the control station apparatus 680 similar to the apparatus 570 is controlled by a four-way plug 681 adapted to connect a tuned vibrator to the pilot wires through condensers 684, 685 and to disconnect the wires from the remote control apparatus at the control station. A general alarm signal is initiated at the substation when a change occurs in the condition of substation apparatus, this change causing operation of a member such as a flick switch 513 whereby relay 561 is energized to send an alarm. If the selectors are in normal zero position buzzer 668 and red lamp 667 are caused to signal and an express selecting cycle takes place as in the system shown in Fig. 6. In all positions other than the normal zero position the relay 561 through contact 563 operates a tuned vibrator 565 and the high-frequency currents generated are superimposed on the two pilot wires and received by a tuned general alarm relay 695 adapted to operate a buzzer. Automatic correction of meter readings. In both of the systems shown in Figs. 6 and 7 means are provided for initiating periodically a complete selecting and metering cycle whereby the records on all the meters are periodically corrected. Referring to Fig. 6, the meter switch 410 is adapted to be operated electromagnetically by means of a coil 416 which may be energized and de-energized at intervals under the control of contacts 417 operated by a constant speed motor indicated by 418. The motor may be cut out of action by a hand switch 419. The apparatus shown in detail in Figs. 8 and 10 comprises a. constant speed electric motor R geared to a drum S which is formed with grooves S adapted to engage a number of pairs of adjustable rollers T, TI. One of the rollers is slightly in advance of the other, the relative positions being adjustable so that the period of making or breaking a circuit controlled by the rollers may be accurately adjusted. Each roller is carried by a lever arm T provided with a projecion T adapted to close a pair of contacts U. The two pairs of contacts corresponding to two adjacent rollers T, T' are connected in parallel or alternatively can be replaced by one pair. The drum may operate contacts controlling the circuit of the coil 416, Fig. 6. or, as shown, may operate sets of contacts U , U', U , U' corresponding, respectively, to contacts on the meter switch 670, Fig. 7. The grooves S' correspond to the number of selector positions. The circuit of each metering source is, in turn, established for a predetermined interval. In an alternative arrangement shown in Fig. 11, a time switch V closes its contacts V for a brief period at predetermined intervals. The contacts V in parallel with selector contacts V which are closed in all positions of the selector except the normal position, are in the circuit of a relay W having a time delay in its operation. The contacts W after the delay are closed to energize a second relay X which locks up at contact X , at X completes the circuit of a third relay Y, and at X' completes the circuit of a coil Z adapted to act electromagnetically on the meter switch. The relay Y at Y' opens the circuit of relay W and after a time delay operates Y to short-circuit X, whereby Y and Z are de-energized. The de-energization of Y re-establishes the circuit of W through the selector contacts V and the relays again operate in sequence, the cycle continuing until zero position of the selector is reached where the apparatus comes to rest until the time switch V again operates. Specifications 307,379 and 333,172 are referred to.