Contacts on the system inform the control unit whether the track is occupied or free. Here we show how feedback modules can be connected.
No matter whether a shuttle line, a semi-automatically operated staging yard or fully automatic block sections, a feedback system is always needed. The way it works is simple: As soon as a train passes contact points and activates, this is reported to the control unit. This is done electrically by contact tracks that send an analog switching pulse to the s88 feedback module, which forwards the information in digital form to the control unit. This allows a track busy indication in the layout of a Central Station 2 or 3 and, depending on the programming, an event is triggered and thus a signal or a turnout is switched or a route is activated. Prerequisite for a status request at the track is a feedback, which can be done in two ways in two-wire systems. Either by means of (reed) switching contacts, which switch through a magnet placed under a vehicle. The second option is the consumption reporting section, where one side of the outer rail is electrically isolated and connected only to the feedback decoder. On the section, driven locomotives or illuminated cars influence the circuit, which leads to a busy signal in the entire monitoring area. Therefore, these vehicles can be used as a permanent contact for two-rail systems in all gauges.
Consumption signalling tracks
Consumption signal tracks connected to an S88 DC (Art. 60882) detect if there is at least one power consumer in the monitored area. Powered locomotives or lighted cars trigger this consumption detector by at least two electrically connected metal wheels, not by single wheels or plastic wheels. Instead of insulating sleeves (item 74030), Minitrix offers insulating rail connectors (Minitrix item 66539) or separating tracks (Minitrix item 14982/-4/-6).
Switching contacts
Switching contacts on the s88 AC (Art. 60881) are triggered by a magnet that is attached to a rail vehicle and enables safe switching. Reed contacts are well suited for control currents. When installing, make sure that they are in the correct position so that the reed contact responds to the magnetic field. When wiring, ground return is required for each contact. At Minitrix there is a contact track with magnetic switch under item number 14980.
The s88 decoder is the basis of today's feedback system for the CS2 and CS3 and is available in two variants. At the s88 AC feedback module (Art. 60881) only switching contacts can be connected, which switch against the ground connection, for example reed contacts. On the other hand, the s88 DC feedback module (Art. 60882) indicates whether there is a power consumer - such as a locomotive - in the monitored area.
As the CS3 basic version (Art. 60226) does not have an independent s88 connection for feedback modules - in contrast to the CS3+ (Art. 60216) - a Link s88 (Art. 60883) is required in any case to integrate further feedback modules 60881 or 60882. A Link s88 can also be connected directly to the CS3+ and since this always requires its own power supply (Art. 66360), the feedback is independent of the system current. In addition, the other feedback modules connected to the BUS system are also supplied with power via this. Even the earlier decoders 6088 and 60880 can be used on BUS 3 of the Link s88. The Link s88 still has 16 own feedback contacts, which like the connections at the AC decoder 60881 report contactors that switch against rail ground. The Link s88 is connected to the seven-pin Märklin device connector on the rear of the Central Station. Alternatively, connection is possible via a terminal (Item 60145), which can also be located at a distance from the Central Station - for example, at the staging yard - using an extension cable (Item 60126).
