Telemetry

Note: this has nothing to do with SCADA. MOTOTRBO radios can act as a data bearer for SCADA equipment however.

Telemetry is a MOTOTRBO feature that allows customer to remotely control or monitor equipment.

Higher tier MOTOTRBO radios support telemetry functionality in digital mode. Both the MOTOTRBO portable and mobile, have either 3 or 5 General Purpose Input/Output (GPIO) lines on the radio accessory connector, which can be connected to external hardware. With this, the originating radio can send a telemetry command to another radio. Sending the telemetry command can be triggered either by GPIO pins or a programmable button on the radio or microphone.

Telemetry commands instruct GPIO pins on the target radio to be set, cleared, toggled or pulsed. The telemetry commands can also be used to query the status of GPIO pins at the target radio. It also enables the target radio to display a programmed Text Status Message or act on a telemetry command received from the originating radio.

In the case of the portable, a telemetry cable (PMKN4040A) is required which informs the radio that non-data cable is connected. This cable is terminated into a D25 male plug.

Potential Applications

A popular example of how MOTOTRBO can be used for telemetry is a reservoir control system. In this application, the reservoir is fitted with two float switches: one switch closes when the reservoir is full and the other switch closes when the reservoir is empty.

These switches are connected to a MOTOTRBO radio. Since there is no AC power at the reservoir, a DP4400 can be used, which is powered from a lead-acid battery and small solar panel. The radio will have minimal current drain, as it will not be party to any calls and will only transmit when either of the switches change state.

At the other end is another MOTOTRBO radio - it could be a mobile or a portable. This radio is connected to a pump**. The pump draws water from the river and fills the reservoir. This radio is powered from the AC supply to this location (solar could be used here too).

Between the pump and radio is a simple control circuit. This circuit provides soft start and power factor correction for the electric motor inside the pump. The control circuit also provides a low level input for starting and stopping the motor. When the input is high, the motor will run and as soon as the input goes low, the motor will stop.

So as the reservoir empties, float switch A closes and causes radio 1 to send a telemetry command to radio 2. Radio 2 reacts to this command by toggling the pin connected to the motor controller. The pump starts and the reservoir fills. As soon as the reservoir gets to a certain level, switch B closes and radio 1 sends a telemetry command to radio 2, which turns the pump off.

Radio 3 (not shown above) also has the option to manually start the pump by pressing a pre-programmed button. Pressing the button has the same effect as closing float switch A or B. This radio would be in the hands of the farm workers allowing them to switch the pump on for whatever reason.

CPS/RM settings

Telemetry Button refers to the programmable button on the radio. This can be a mobile or portable. For easy refence, a Description can be added.

Telemetry VIO defines which GPIO should be used for the input or output. The GPIO is configured in the Accessories set.

Action defines what must happen when that particular telemetry input is triggered. Which actions are available depends on whether it is associated with a button or VIO. The following choices are available:

1. Send Status is an output command that sends the status of the radio's triggered VIO line to another radio. The receiving radio will receive the status of triggered VIO line and pass the binary information to its own VIO. The status will only be sent when the VIO line changes from inactive to active.
2. Send Status with Text is an output command similar to Send Status but, in this case, it also sends a text message to the requesting radio. Like Send Status, it is only possible to receive this when a Telemetry VIO goes active on the requesting radio.
3. None means this button/VIO is not used.
4. Send Pulse Command is an output command that will send a Pulse instruction to another radio. The target radio and VIO is configured in Call and Target VIO (described below).
5. On Pulse Command is an input command, which on receipt of a Pulse instruction from another radio will generate a pulse with a duration equal to the Pulse Time (below).
6. Send Query Status Command is an output command that is sent out to request for the status of the VIO lines of another radio.
7. Send Toggle Voltage Command is an output command that sends a Toggle instruction to another radio. It is up to the receiving radio to trap this command and to Toggle the line.
8. On Toggle Voltage Command is an input command, which on receipt of an On Toggle Voltage instruction, will toggle the VIO.
9. Send Voltage High Command is an output command. The radio sends a Voltage High instruction to another radio. It is up to the receiving radio to trap and set the line high.
10. Send Voltage Low Command is an Output Command. The radio sends a Voltage Low instruction to another radio. It is up to the receiving radio to trap and set the line low.
11. On Voltage High/Low Command is an Input Command that traps a Voltage Low or Voltage High instruction from another radio and sets the line to the active state (applicable to Telemetry VIO only).

Pulse Time sets the duration of the pulse presented on the target VIO when the On Pulse Command Action is selected (see above)

Mode determines in which mode the telemetry is will sent or received. The choice are: Capacity Plus; Digital and Local. For Capacity Max systems/radios, use Digital.

Channel Zone and Channel determine which zone and personality will be used to send or receive the telemetry.

Call and Target VIO set the destination for the the telemetry input while Text Message allows the technician to select which pre-programmed text message will be sent if the action requires this.

See Also

• Text Messaging
• Accessory Connector