1. Failsafe function (two identical receivers at the same frequency):
If one receiver fails, all servos are switched over to the second receiver. The pilot can continue to fly without interference and without any adverse effects. The receiver should exhibit a failsafe function (e.g. at the PCM). But even when using two PPM receivers without the failsafe function, a servo signal missing due to a receiver defect can be used for switching.

2. Pilot backup (two receivers at different frequencies):
If the receiver OR the pilot's transmitter fails, all servos will be switched over to the second (backup) pilot. He can then land the model safely.

3. Teacher-Student Function (two receivers at different frequencies):
The teacher can switch back and forth between the two receivers by means of a switch channel on his transmitter. The student can then take over all of the functions of the model, if need be, using his own transmitter. In critical situations the teacher can gain back full control with one single switch operation. In this way every model pilot can control his friend's model (provided he has the DPSI TWIN installed) with his own transmitter and his own stick typing. He simply needs to program the model parameters into his transmitter and put the appropriate crystal in the second receiver.

The DPSI TWIN also functions as a data logger, i.e., all relevant operational data of the last flight is saved in non-volatile memory. The data can then be read by a PC. The possible cause of a crash can then be determined from the information (battery voltages, output voltage, failsafe signals, receiver interference).

To obtain information about the status of the entire system, the DPSI ICE (Information Center) can be attached to the DPSI TWIN, as an option. All of the relevant information is displayed in this cockpit instrument (1.6" (40mm) diameter) by means of 8 LEDs (which receiver is currently active, how many interferences have occurred, are the batteries dying, etc.). It is then easy to tell after each flight whether any interferences occurred. This information can be used to promptly determine defective receivers and/or crystals, for example. In the case of a faulty range test, new positioning of the receiver or antennae - among other things - can be used to improve reception. It is thus possible to achieve qualitative improvements of the entire receiver system.

Characteristics of the DPSI TWIN:

• Failsafe operation with automatic switching between two receivers.
• Teacher-Student operation with manual switching between two receivers
• “Pilot backup” using two separate frequencies (2 transmitters, 2 receivers) is possible
• All control functions remain completely intact during the changeover from one receiver to the other
• Open programmability of the failsafe servo position
• Optional PC interface with PC software for reading and programming the data is available
• Data logger, i.e. important parameters of the last flight are saved and can later be read via PC
• 2 x 8 receiver channels with power distribution to 25 servo connections
• Two failsafe channels for evaluating the receiver function
• Double power supply with controlled voltage for receivers AND servos
• Output voltage in 4 stages programmable from 4.8 volts to 6.0 volts
• Compliance with all manufacturer specifications for RC receiving stations
• Continually constant servo controlling torque from constant power supply
• Lilon / LiPoly / LongGo batteries can be used
• 5 and 6-cell NiCd / NiMH batteries can be used without restrictions
• Only about 0.4 volts dropout loss at 4 amps load
• Electronic, failsafe on/off switch with additional connection option for the DPSI ICE (Information Center)
• Short circuit-proof servo pulse amplification in power-saving APP technology (Advanced Push Pull)
• HFIB (High Frequency Interference Blocking), blocking of injected high frequency interference from long servo-cables (separate for each servo)
• Having a maximum load of up to 70 amps peak current
• IVM (Intelligent Voltage Monitoring) – intelligent voltage monitoring with acoustic status indicator for four different types of batteries (programmable)
• Cable-free system, i.e. all inlets are pluggable and therefore replaceable at any time
• Special grounding concept for trouble-free operation and maximum safety
• High-quality plastic housing with integrated holding clamps for the battery connector plugs
• Large-surface cooling elements for deflecting heat loss
• Each system 100% inspected and provided with a unique serial number
• Registered design protection
• Weight: 7.5 oz (215 grams)

Similarities with the DPSI RV:

• In general, we recommend an output voltage of 5.5V for operating the RC receiver station. The semi-conductors used in the electronics are generally designed for this maximum voltage. All of our systems are set to an output voltage of 5.5V at the time of delivery. The controlling torque of the servos changes insignificantly from 5.5V to 6.0V. What is important is the stable voltage at the servos, which does not break down even at full load. This is a given in the DPSI TWIN.
  
  
• The linear longitudinal regulators, which are used to regulate voltage, result in losses that are transformed into heat. Regulation functions like a "valve". A high voltage enters in the front
  (e.g. 7.4 volts), while a regulated, lower voltage comes out from the back (e.g. 5.5 volts). The difference between the high input and the low output voltage (in this case 1.9 volts) must of course go "somewhere" (in the case of a valve through the overflow). In the case of voltage regulation, this difference is transformed into heat. That is why the DPSI RV systems have cooling surfaces with generous dimensions, which become warm in the case of a very high load. Simply using switch-mode voltage regulation (such as with a battery charger), will allow a smaller cooling surface. A switch converter (switch-mode regulation) is very expensive, however, and for the required maximum currents (up to 50 amps) would result in considerably higher weight, considerably higher costs and an increased HF interference potential (for this reason, there are huge ferrite rings on the battery supply lines of high-quality battery chargers). Switch-mode regulation for RC power supplies of this magnitude is therefore ruled out.
  
  
• The power electronics in the DPSI TWIN is identical to that of the DPSI RV LDO. Here, too, 10 (!) high-performance semi-conductors are used. The complete circuit has a dual design: double electronic switch with self-locking function, two double decoupling diodes and double voltage regulation each with two high performance semi-conductors for optimal dissipation of heat. This multiple redundancy prevents the interruption of power supply in the event of a particular component failure. For this reason, the DPSI TWIN is also used for power supply in reconnaissance missiles and drones.
  
  
• The switching technology guarantees a no-signal current consumption in switched-off position, which does not discharge the batteries. This quiescent current is less than 1µamp! This ensures that no damage to the batteries can occur from a "creeping" discharge. This is achieved, in part, because the switching procedure is not controlled by the micro-controller and the micro-controller is therefore completely shut down in the switched-off status (i.e. not running in standby mode, which increases the quiescent current). Another advantage of this solution is that a failure or unintentional resetting of the micro-controller cannot shut off the DPSI TWIN.
  

The design of the entire DPSI RV systems (with respect to size and weight) was based on intricate measurements. A 9 feet (3m) test model with 15 digital servos and a self-developed data logger were used for the design. The current consumption of the entire receiver station was recorded and evaluated in millisecond resolution during several videotaped measuring flights. An unique current consumption could thus be assigned to each maneuver and the median power of a complete flight could be calculated. For the first time, the actual maximum power occurring could also be determined from these measurements. A 100% reserve was calculated into the data that was acquired in this way and the required cooling capacity (for LongGo batteries) and thus the size of the DPSI RV systems determined from the results (also in relation to the maximum number of servos). The recorded data was fed into an electronic "flight simulator". Using intricate laboratory equipment, real flights of each model with an arbitrary number of servos can be simulated by means of nominal value scaling. The algorithm that rates the battery voltages, among other things, is based on these results. Even if the expense appears to be high: real facts can only be produced from real measurements, which are then incorporated into development and ensure product quality.