Installation and Setup: RTMS Echo Sensor

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) CAT5e 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 source provides power to other equipment in addition to the Echo sensor, a filter is recommended (see Cabling: Power Filtering).
Figure 1 shows a block diagram of the connections if separate surge suppressors are used for power and communications.
Figure 1
Figure 2 shows the same diagram if a single surge suppressor is used. For information about connections for serial communications, see Serial Communications Using Sx-300 Protocol.
Figure 2
NOTES:
  • It is the responsibility of the installer to provide all equipment inside the breakout box and cabinet.
  • The maximum length of the communications (data) connection from the Echo sensor to the cabinet is 330 ft (100m). For lengths greater than 330 ft, an Ethernet extender must be used.
  • If using a 12 volt power supply, it is recommended that the cable length from the power supply to the Echo sensor be no more than 50 ft (15.24m) in length.
  • If the distance from the Echo sensor to the power source is greater than 50 ft (15.24m), a power supply booster may be required to ensure there is a constant 24VDC supply to the sensor.
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