SapIP – IRT Instruction Manual 1/23/2017
Page 26
Dynamax, Inc.
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The unit will sleep 8 seconds assuming the EEPROM ‘SERIAL_COMMAND MODE’ is off.
Otherwise, the unit will sleep for 1 second, then wakes up and turn on the radio for 30 milliseconds
to check for any incoming commands. It will repeat this cycle 8 times, making a total of 10
seconds for sampling and sleeping
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Upon waking, the code will either receive another reading or send an output to the radio and to the
telemetry DC output. An EEPROM switch determines the number of minutes between outputs. The
six samples taken 10 seconds apart are then averaged and added to an accumulator. These one
minute readings are averaged in turn while waiting for the output timer. So, if the interval is 1
minute, each output is an average of 6 samples. If interval is 10 minutes then the output is an
average of 60 samples, etc.
4.
Format Data String
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An EEPROM switch determines whether the radio is used. If it is not please skip to the “Output
DC Telemetry Signal” below.
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The battery is checked exactly as it was in the initialization routine. If it fails, the program halts
(attempting to charge the battery) and the LEDs dimly blink (150 ms) every 10 seconds.
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Next, a data packet is constructed which contains the header information (see appendix), frame
number, node ID, battery voltage, object temperature, sensor ambient temperature and the
checksum. Each item is separated by a comma. i.e. “1, 17, 5.1, +32.70, +24.80/cr”
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Frame Number: A single digit which starts at 0 and increments during every output sample (up to
9, restarting at 0). This number is also imbedded in the API header so that the ack/nack machinery
knows which packet goes with each feedback packet.
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4 Hex Digit / 32-bit Node ID: This is a hexadecimal ASCII string read out of the EEPROM. The
node ID identifies this particular sensor board in a network.
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Battery Voltage: Formatted as an xx.x string in volts. Maximum operational voltage is 18.0 V.
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Object Temperature: Formatted as a +/- xxx.xx string in degrees C. All data is averaged to remove
noise.
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Ambient Temperature: This is the sensor’s body temperature which is also formatted as a +/-
xxx.xx string (degrees C).
5.
Radio to Coordinator
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Before the packet transmission a delay is imposed which varies depending on the unit serial
number.
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Note: Delay = serial No. Least Significant Byte x 10 ms. From to 0 to 150 ms.
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Next, the radio is then woken up from sleep mode and is followed by packet transmission.
Ack/nacks are then interpreted and is data re-transmitted if needed.
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Radio is then put back to sleep.