RoboteQ AX2550/2850 user manual Reception Watchdog, Transmitter/Receiver Quality Considerations

Reception Watchdog

For best results, reliability and safety, the controller will also perform a series of correc- tions, adjustments, and checks to the R/C commands, as described in the following sec- tions.

Reception Watchdog

Immediately after it is powered on, if in the R/C mode, the controller is ready to receive pulses from the R/C radio and move the motors accordingly.

If no pulses are present, the motors are disabled, and the controller’s display will scroll alternatively the letters “no ctrl” as shown in Figure 51 below.

FIGURE 51. “No control” message will scroll when no valid radio signal is present

After powering on the R/C radio receiver and transmitter, and if the wiring is correct, the controller will start receiving pulses. For a preset amount of time, the controller will moni- tor the pulse train to make sure that they are regular and therefore genuine R/C radio com- mand pulses. After that, the motors are enabled and the LEDs will display a pattern related to the actual motor direction (see Figure , “Motor Direction Status,” on page 66).

This power-on Watchdog feature prevents the controller from becoming active from para- site pulses and from moving the motors erratically as a result.

Similarly, if the pulse train is lost while the motors were enabled, the controller will wait a short preset amount of time before it disables the motors. If the pulses reappear during that time, the controller continues without any breaks. If the communication is confirmed lost, the “no ctrl” message is displayed again.

Note: the Accessory Outputs C and D will be turned Off when radio is lost.

Important Notice about PCM Radios

PCM radios have their own watchdog circuitry and will output a signal (normally a “safe condition” value) when radio communication is lost. This signal will be inter- preted by the AX2500/2850 as a valid command and the controller will remain active. To benefit from the AX2500/2850’s radio detection function, you will need to disable the your PCM radio watchdog.

R/C Transmitter/Receiver Quality Considerations

As discussed earlier in this chapter, the AX2500/2850 will capture the R/C’s command pulses with great accuracy. It will therefore be able to take advantage of the more precise joysticks and timings that can be found in higher quality R/C radio, if such added precision is desired in your application.

AX2500/2850 Motor Controller User’s Manual 79