AFX Technology Group TM701V00 User Manual

Minion 701 Feature Narrative and Installation Guide

WARNING: “THIS EQUIPMENT COMPLIES WITH PART 15 OF THE FCC RULES. ANY
CHANGES OR MODIFICATIONS NOT EXPRESSLY APPROVED BY THE MANUFACTURER
COULD VOID THE USER’S AUTHORITY TO OPERATE THE EQUIPMENT.”

Minion 701 Hardware Description

The Minion701 is designed primarily as a power outage notification device. The hardware requirements of
this device are a close approximation of the requirements of a MinionNet POTS Gateway. Hardware
features specific to this application include battery-powered operation, a user interface lighted pushbutton
and the physical form-factor.

The complete product consists of a Minion 701 board and Telco Modem module in a plastic enclosure, a
wall-wart power transformer and a modular cable to connect to a telephone line.

User interface consists of a ½ inch square, lighted momentary pushbutton switch.

Electrical interface consists of a 2.1 mm barrel connector for the external power supply and a dual RJ-11
modular telephone jack.

The enclosure is a 28mm X 66 mm X 90 mm black ABS plastic enclosure with a door for the 9V battery.
A flat insert in one end provides openings for the telephone and power connectors. A square hole in the
center of the top surface is used by the lighted pushbutton. A recessed area on the top surrounding the
button opening provides for application of an identifying label.

External Power Supply
The external power will be provided by an unregulated 9VDC wall transformer. This power supply will
provide the operational power for the device and will also be used to detect line voltage fluctuations
(brownouts and blackouts). The rated current from the transformer will be 200 mA. It is necessary to load
the transformer to a significant percentage of its rating in order to ensure that the output voltage is
proportional to the line voltage. The minion device will normally represent an insignificant load. The
voltage measurement circuit will include a 100 ohm, 1 watt resistive divider. This will load the transformer
to 50% of its rating and minimize the effect of load changes as the modem is turned on or off.

The external power supply connects to the device with a 2.1 mm barrel connector with (+) on the center
pin.

Battery
The battery will be a 9V alkaline primary cell.

Typical ratings for an industrial alkaline battery show a life of 6 hours with a constant load of 100 ohms
and an end-of-life voltage of 5.4 volts. Therefore, the average voltage is about 7.5 volts, average current is
about 75 mA and capacity would be about 450 mA-Hours. Since this is a 3.3 volt design and we use a low­dropout regulator the actual life may more than double this figure.

Modem current is listed as 21 mA max at 3.3 volts during operation and 55 uA max during power-down.
The duration of an outage notification call will be approximately 30 seconds which will be the only time
that the full-power load will be presented to the battery.

Minion current requirements are 7 mA at 3.3 volts and 30 uA during sleep with the realtime clock running.
Normal MinionNet operations turn the radio transceiver on for one second every two minutes when
operating on battery power.

The table shows estimated device longevity while operating on battery power. The last three columns show
a life expectancy for the battery after using the modem for three different amounts of time. All of these
numbers should be viewed as worst-case estimates; performance in real-world situations should be
significantly better

Modem Use During Normal Sleep Maximum

10 minutes 2 hours 6 hours

Sleep

Normal

Sleep

(1 : 120)

Light
Sleep

(1 : 60)

Continuous

Calling

Battery 450 mA-H 450 mA-H 450 mA-H 450 mA-H 445 mA-H 394 mA-H 282 mA-H

Minion 30 uA 88 uA 147 uA 7 mA 88 uA 88 uA 88 uA

Modem 55 uA 55 uA 55 uA 21 mA 55 uA 55 uA 55 uA

Lifetime 5294 hours

(220 days)

3147 hours
(131 days)

2239 hours
(93 days)

16 hours 3112 hours

(130 days)

2775 hours
(115 days)

1972 hours
(82 days)

To summarize:

1) The battery is only used while the main power is disconnected.

2) If the external power is on continuously the battery will last for its rated shelf life.

3) The battery life expectancy without external power is four (4) months.

4) Each hour of modem use during a power failure will reduce that expectancy by eleven (11)
days.

Power Supply
The power supply section of the device provides for both external (wall) and internal (battery) operation.
These nominal 9V supplies are regulated down to 3.3V by a Low Dropout analog regulator. Diode
protection ensures that reverse connections will not damage the device. The protection diodes also ensure
that power is supplied only by the wall transformer during normal operation. The transformer voltage
being slightly higher than the battery voltage reverse-biases the battery protection diode and ensures that no
current flows from the battery.

Resistive dividers are used to establish measurement points for A/D converters used to measure the
voltages of each supply. The measurement points must be between 0 and 3.3V, the range of the A/D
converter using the regulated Vdd as a reference.

A 100 ohm, 1 watt divider chain scales the external supply to 1/4 of its value and provides a load for the
transformer. A series diode protects the analog input against reverse connection or inadvertent use of an
AC transformer.

A 1 Mohm divider scales the battery to 1/4 of its value and presents an insignificant continuous drain on the
battery. A 0.1 uF capacitor is used to provide charge storage at the measurement point to ensure accurate
measurements by the A/D converter. A series diode protects against accidental battery reversal.

Microcontroller
The microcontroller is a PIC controller from Microchip Technologies. The single-chip controller combines
processor, flash program store, EEPROM non-volatile data storage, RAM memory, clock oscillator, real­time clock, parallel I/O ports, serial I/O and A/D converters.

The asynchronous serial I/O port provides communication with the modem module. Asynchronous data
and commands are transferred at 2400 baud.