Ge mac 5000 operators manual

Since one terminal is always zero grounded and the other is driven with a variable duty cycle between zero and 12V, the feedback signal is positive regardless of motor direction. C filters the switching noise from feedback voltage. Note that the frequency and duty cycle of the motor drive signal are random. This serves to reduce EMI by spreading any emitted noise across a wide frequency spectrum. An RC snubber R and C suppresses ringing on the motor lines. Larry maintains precise motor speed control by comparing the frequency of the tachometer pulse train emitted by the motor's integral encoder to an internally generated reference frequency derived from Larry's resonator.

Larry processes motor position information on both edges of both encoder signals for a total of 64 loop correction cycles per rotation of the motor shaft. This high angular sampling rate allows Larry to achieve accurate and smooth speed regulation down to zero speed. If the error variable saturates "on" for more than a predetermined time it is assumed that the paper drive torque has become excessive, or the motor has stalled. This condition is reported as a Paper Jam Error. Similarly, if the servo error variable saturates at "off" for more than a predetermined time, it is assumed that the someone is pulling on the paper with a force that exceeds the paper drive system torque, and as a result paper speed has been pulled out of regulation.

This condition is reported as a Paper Pull Error. Cue Hole Sensor Cue and out-of-paper conditions are sensed via the thermal print head's integral optical cue sensor. Larry monitors the cue sensor's logic output. Cue Hole Detection Larry monitors the output of the cue sensor to detect the presence or absence of paper under the sensor, and hence the absence or presence of cue holes. Paper Tracking Fault Detection Larry monitors the cue sensor for abnormally long paper travel without encountering a cue hole.

This condition is reported as a Paper Fault. Paper Out Detection Larry reports excessive paper travel without sensing paper as a paper out condition. Analog Inputs Larry digitizes four analog inputs at eight bits resolution each. Two inputs handle external analog signals, such as those produced by ergometers or analog output blood pressure monitors. Thermal printhead temperature is measured for use in compensating strobe pulse width to maintain constant print density over a wide range of thermal printhead temperatures.

The output of the thermal printhead pixel test hardware is also digitized to allow the resistance measurements on individual print elements. This continuous operation is necessary for Moe to accurately monitor the battery state of charge and detect power key presses. System Startup When the system is off and the user presses the power key, Moe begins the startup sequence. Moe then keeps tabs on the system via a software watchdog that must be serviced by specific BBus activity from the StrongARM.

Moe must constantly toggle the MAX watchdog input pin or suffer the consequences. NOTE Moe presumes that the main power rails, which it controls, are off when it powers up. If Moe should malfunction while the system is already powered it is likely that the HC05 will incorrectly identify itself as Larry. If that request doesn't arrive in time, Moe places the system back in reset and removes power. In the event of main CPU failure that causes loss of function yet maintains Moe's watchdog function, a manual forced power-down function is provided. A continuous press of the power key for a period greater than 5 seconds will force the system to shutdown.

The battery connection is maintained through the hinge so the CPU board is capable of operating for a limited time with the door open.

An LT switchmode charge controller Battery Charger provides battery charge current. This device monitors both battery and power supply current draw and maintains both at safe levels.

As system current draw increases, the Battery Charger automatically decreases battery charging current to maintain total power supply current below the design level nominally 1A. Nominal charge current is also 1A, which is achievable only when the system is off.

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R21 ensures that the charger remains off when Moe is starting up. Lid Open Detection A self-aligning connector routes power and motor signals from the power supply compartment to the CPU board. Moe monitors this line to detect lid open conditions that are reported to the system software to avoid misinterpretation of motor fault indications.

When the door is open, the motor connections are lost and Larry receives no tachometer feedback from the motor. Without knowing the cause of the lost tachometer info, Larry can only respond with a paper jam condition. Moes knowledge of the lid state is used to suppress this error message as well as prevent further print operations.

The battery charger will not be enabled unless the DC power supply voltage is above approximately 21V. Battery Pack The MAC uses a cell NiMH Nickel Metal Hydride battery pack with integral thermal sensor for charge termination detection and self-resetting thermal fuse for short circuit protection. Charge current and normal system operating power are obtained from the AC power supply. The charger circuitry monitors both battery charge current and power supply output current.

The battery is always charged at the maximum rate possible but system power demands take precedence over charger demands.

The charger automatically reduces charge current as required to keep the AC power supply output current within specified limits. In the extreme during printing charging ceases and energy is taken from the battery to meet peak system demands.

When system power draw declines, all excess power supply capacity is once again delivered to the battery. Battery Temperature Sensor Moe uses a thermal sensor inside the battery pack to determine when to terminate charge. During normal charge, the electrical energy obtained from the power supply is stored in chemical reactions in the battery.

When the battery reaches full charge there are no more reactants available in which to store chemical energy and the supplied charge power is converted directly to heat. The sudden rise in pack temperature caused by this release of heat is an indicator of MAC resting ECG analysis system Equipment Overview: Theory of Operation full charge.

When the rate of pack temperature rise exceeds a certain threshold, charge is terminated. This is the only normal charge termination mechanism. Abnormal conditions such as battery or ambient temperatures beyond spec, or excessive pack voltage, may also terminate charge. Once fully charged, the battery is maintained by low duty cycle charge current pulses.


Absurdly low voltage readings from the battery temperature sensor indicate an open thermistor. This is used as an indication that no battery pack is present. This can easily occur since the two pins are adjacent. Battery Voltage Sensing Moe continuously monitors battery voltage during operation. Excessively high pack voltages during charge will cause charge termination. If battery pack voltage falls below a predetermined threshold during operation, the battery gauge is immediately cleared to zero and the main CPU is notified of the critically low voltage. Ambient Temperature Sensor Extreme ambient temperatures are not favorable for battery charging.

Rapid changes in ambient temperature can cause premature or delayed charge termination by altering the pack's temperature. Moe monitors ambient temperature via the thermistor TEMP to ensure that charging occurs only within the safe temperature range as well as to minimize the effects of changing ambient temperature on charge termination particularly to avoid premature termination, which would give a false full reading on the gas gauge.

The battery and ambient thermistors are the same type and value to ensure reasonable tracking. Capacitors C15 and C55 filter noise from the temperature sense lines. Thermistor Bias Switch To reduce quiescent power consumption when the system is turned off, a switch disables bias current to the battery and ambient thermistors. Q8, under control of MOE, switches the low side of the thermistor bias networks.

Charge Light Moe provides power to the amber charge light in the power supply compartment. Four conditions may be indicated:. Battery charged light is off Battery needs charge light blinks twice per second Battery is critically low light blinks once per second Battery is charging light on continuously. The charge LED is contained in the power supply compartment and is disconnected from the CPU board when the cover is open. When the cover is closed electrical connections are re-established through the selfaligning connector.

As the connections are made in random order, there is a possibility that the VPS and XChargeLED drive lines can connect before the power supply ground. This places a high potential across the LED drive circuit as the power supply attempts to return its output current through the LED. To prevent damage to the LED and driver, it is implemented as a constant current source with a large compliance voltage. Q6 level shifts Moes output to the level required to turn off Q7 during off periods.

By integrating the current flow, Moe is able to maintain a reasonable estimate of the battery packs state of charge. The current monitors full-scale range is set to a value that is likely to encompass normal operating currents. Peaks above this level 6Amps are clipped.

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The effects of this clipping are minimal as such high density printing occurs for short periods of time and represents only a small portion of system energy consumption. Quantization error limits the ability to measure the small current that flows when the system is off. To compensate for this, Moe presumes a small constant quiescent current flow from the battery.

This flow serves to drain the gauge at a rate estimated to mimic the self-discharge and system quiescent current draws. Current monitor gain is set by R6 and is nominally 1. A low pass filter R7 and C1 provides filtering to remove switching noise from the signal. Untested Nominal Operating Time Specs These specifications are affected by battery pack characteristics.

While they are of interest, it is not possible to test them in production. These are nominal specs and are only guaranteed for a new battery pack of 3. As the following specs are for a system that is turned off, they are deliverable by the CPU regardless of other system components. Nominal charge time: 5 Hours Max off time from gauge full till loss of clock: Max off time from gauge just empty till loss of clock: Max off time from panic shutdown till loss of clock: Maximum time from removal of live battery to loss of clock: 1 Month 3 Days 1 Day 6 Hours.

Use this picture for reference when installing trolley options.