Wireless Pump Control

To easily do Wireless Pump Control, Raveon has added a “MIMIC” mode to the M7 series of data radio modems. It works for not only wireless pump control, but also to remotely control most any electrical device that is turned on and off with a switch or relay.

The MIMIC mode allows two or more M7 data radio modems to “mimic” each other’s digital I/O.  When in the MIMIC mode, the M7 will periodically transmit its digital status.  The M7 will also continue to operate as a radio modem, sending/receiving data using pins 2&3 of the DB9, but the other I/O pins of the DB9 will be used for digital input/output. The MIMIC mode also has a fail-safe setting, so that in the event the radio link is broken, the receiving MIMIC radio will automatically set the MIMIC output to a pre-defined state.

Normally, the Serial I/O connector operates like an RS232 serial interface.  If the MIMIC mode is enabled, the operation of the radio is modified to transmit the digital status of the INPUT0 and INPUT1 pins across the radio link, and output their status on the OUT0 and OUT1 pins.

There are two aspects to the MIMIC mode:

  1. The transmitter that sends the status of its digital inputs.  This is enabled with the MIMIC X Y command.
  2. The unit that receives the over-the-air MIMIC message, and sets its digital outputs to match the inputs of the sending station.  This function is enabled with the ATIO 1 command.  ATIO 1 configures the DB9 serial port to operate with RS232 signal levels, and use the digital control lines for digital I/O instead of RS232 flow control.  ATIO 0 turns off MIMIC reception ability, and the digital I/O pins will operate as flow control signals.

The goal of the MIMIC mode is quite simple: Flip a switch at one location, and have something at another location turn on or off.

Filed under: SCADA and Telemetry | Posted on November 2nd, 2010 by John Sonnenberg

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