Connecting Power/Communications

After the RTMS Echo has been mounted to the pole (see Mounting the Sensor) the connections for power and data communications must be made. For cable pinouts see Cabling: ISS Provided Cable.

The RTMS Echo is a constant power device that requires in its basic configuration a maximum of 8 watts of power. Electrical power has two components, voltage and current; both must be available in the correct ranges to operate the RTMS Echo. The voltage must be between 12 and 24 volts DC with the voltage level read at the RTMS Echo. Voltages below 12 volts will be insufficient to power the RTMS Echo. Voltages above 30 volts could cause damage to the sensor. Losses in the cable must be addressed in setting the voltage to be supplied to the unit. Current in sufficient quantity must be available: at 12 volts, the RTMS Echo will draw roughly 660 mA of current; at 24 volts roughly 330 mA. Using an adaptor that provides 12 volts and 100 mA of current means that the total power to the RTMS Echo will be 12*0.1 = 1.2 watts, or roughly 15% of the power needed to turn on the RTMS Echo.

A 50 ft (15.24m) Cat 5e cable containing wires for both power and communications is included with the RTMS Echo sensor. It is strongly recommended that surge suppression be provided for both power and communications. In addition, if the power source in the breakout box is solar or if the the source provides power to other equipment in addition to the Echo sensor, a filter is recommended (see Cabling: Power Filtering).

Figure 1 below shows a block diagram of the connections if separate surge suppressors are used for power and communications. Figure 2 shows the same diagram if a single surge suppressor is used. For information about connections for serial coimmunications, see Serial Communications Using Sx-300 Protocol.

Figure 1 This is a picture of the software. Figure 2 This is a picture of the software.