31C1936 CONTROLLER BOARD CONTENTS 1 INTRODUCTION .............................................................................................................................................................1 2 GENERAL OPERATION.................................................................................................................................................3 2.1 CONNECTOR AND SIGNAL DEFINITIONS .................................................................................................
31C1936 CONTROLLER BOARD 3.2.2 L/O Status LED..................................................................................................................................................18 3.2.3 RF Status LED ...................................................................................................................................................18 3.2.4 INTK Status LED ..............................................................................................................................
1C1936 CONTROLLER BOARD 3.9.3 ExtCmd ..............................................................................................................................................................36 3.9.4 SerCmd ..............................................................................................................................................................36 3.9.5 Error ...............................................................................................................................
31C1936 CONTROLLER BOARD 6.9 RF PHASING ...............................................................................................................................................................64 6.9.1 Splitter and Phasing Circuitry ...........................................................................................................................64 6.9.2 Phasing Controls ............................................................................................................................
31C1936 CONTROLLER BOARD 1 INTRODUCTION The MXi802 and MXi1002 transmitters consists of three separate chassis, two amplifier chassis units and one power supply / main control chassis unit. The chassis unit on the top is the power supply / main control that houses the 31C1936 control board, which is the subject of this publication.
31C1936 CONTROLLER BOARD The front panel of the chassis has the ON button and PWR status LED that the operator uses to turn the transmitter ON or OFF manually and the LED will indicate (when lit) whether the transmitter is in the ON state. Of course the transmitter has remote controls that enable the ON/OFF controls to be activated by off-site facilities.
31C1936 CONTROLLER BOARD 2 GENERAL OPERATION 2.1 CONNECTOR AND SIGNAL DEFINITIONS The connectors on the MXi control board are all shown in Figure 29, which is sheet #5 of the Schematic. The individual signals that are associated with each pin of the connector are also given. A brief description of each of the connectors on the board follows. 2.1.1 J1 AMP1 RS232 Connection This connector would normally have a nine-pin ribbon cable attached and routed to the nine pin serial connector of Amplifier #1.
31C1936 CONTROLLER BOARD 2.1.5 J5 Remote Controls This uses a 15-wire ribbon cable to send status/telemetry and receive commands from the rear panel 15-pin Dshell connector. The transmitter must be in ‘Remote’ mode for the commands to be operational, however the output status and telemetry are always current.
31C1936 CONTROLLER BOARD The last signal on this connector is a +12V power supply output that is used to power the MXi main controller board itself. The ground reference is shared with that of the +50V power supply. 2.1.12 J12 Amp2 +50 Volt Power Supply Sensing This uses a six-pin connector that has all the interface connections for the +50V power supply, which is associated with Amplifier #2. Included are an ON command, P/S OK status, the +50V sample and a ground reference from the power supply.
31C1936 CONTROLLER BOARD The +50V external wires are routed through the sensing aperture of the current sensor (though not truly connected through the main control board). The circuitry on the main board converts the signal from the current sensor into a telemetry output. These signals go to an external connector on the rear panel of the control chassis. An external cable will route these signals to the Amplifier #2 chassis.
31C1936 CONTROLLER BOARD . 2.2.3 Jumper E3 – VSWR Trip Disable When installed, this jumper disables the VSWR trip interlock of the transmitter and its controller. This is normally only to be used with setting up the VSWR trip level for the amplifier. In normal operation, this jumper should always be removed, since it removes the VSWR protection from the amplifier. In the presence of a VSWR condition, this could result in damage to the amplifier FET devices.
31C1936 CONTROLLER BOARD AMP1 Current Sensing PkI Position = Analog, measure the Peak Sync Current AveI Position = Measure the Average Power Supply Current 2.2.7 Jumper E7 – Peak/Average Current Amp2 This jumper controls whether the +50V power supply current sensors on the main controller will use a peak detecting circuit or an average detecting circuit.
31C1936 CONTROLLER BOARD power but it was decided that running a +5V supply through the 16 pin ribbon cable on top of the two high current power supplies might result in noise pickup. It was for this reason that the +12V is sent over the 16 wire cable and then regulated near the LCD itself on the front panel interface board. 2.3.2 Error LED and Reset Control The front panel Error LED (DS1) is located on the front panel interface board and indicates if there is a current error condition on the amplifier.
31C1936 CONTROLLER BOARD In ‘System Bypass’ mode, jumper E4 is installed such that when the operator presses the front panel ON/OFF button into the ON state (ie pressed in) then this directly activates the ON/OFF relay K2 without any CPU intervention. In this state, the CPU cannot turn off the transmitter and thus remote OFF commands will not work even when the system is in the Remote mode.
31C1936 CONTROLLER BOARD 2.6 VSWR TRIP AND LOCKOUT OPERATION The MXi has built-in VSWR protection to prevent damage to the amplifier from excessive power being reflected back from the output system. This VSWR protection becomes operational when reflected power exceeds 10% of forward power. The system shuts down the amplifier for a few seconds and then tries to restart again. This is done to check if the VSWR was a temporary condition that could have been caused by a lightning strike nearby.
31C1936 CONTROLLER BOARD 2.7.2 Soft Interlocks There are parameters that the CPU monitors and if they indicate an error condition, the CPU will set the appropriate error flag and issue a log entry. Such parameters are power supply over current and over voltage. Since the power supply has internal protection built in for these parameters there is no need to have the CPU shut the transmitter down on these conditions and so they result in error messages and log entries only.
31C1936 CONTROLLER BOARD 3 LCD GUI INTERFACE AND TOUCHPAD The user interface to the transmitter is mainly accomplished with the front panel LCD that incorporates a touchpad as an integral part of the unit. The touchpad consists of a thin membrane attached to the LCD surface which implements a software-driven menu selection system. The LCD has the capability of displaying a number of different screens, which are selected by the operator via the touchpad.
31C1936 CONTROLLER BOARD The second line of the LCD shows the current state of the transmitter and any important errors that are current. This line typically tells the operator if the transmitter has been asked to be in the ON state. The transmitter is placed in the ON state either by the local front panel ON button or by a remote ON command. If the transmitter has been turned off by the operator, the LCD reports that the transmitter is OFF normally (i.e., it was not due to an error).
31C1936 CONTROLLER BOARD 3.1.3 AMP2 Status LED Status that indicates the condition of RF amplifier #2. The amplifier(s) report their operating parameters to the central control unit via a RS232 serial stream. The central control monitors this stream and will indicate an error if the amplifier stops communicating. This communications must be operating whether the amplifier RF output is ON or OFF.
31C1936 CONTROLLER BOARD • Lit when interlocks Ext1, VSWR Trip and VSWR Lockout are closed (i.e., OK). • Not lit when or one of the interlocks are opened. If this status LED is not lit, then the operator should then check the INTK submenu to determine the source of the problem. Note that the same individual interlock status can be found on the other submenus as well, but the INTK submenu is a place where all the individual interlocks are displayed in one place. 3.1.
31C1936 CONTROLLER BOARD The LCD displays a typical COMB submenu as follows: Figure 6 Combined Power Screen The first line shows the three possible RF values. The first item is the combined forward power denoted as CMB that represents the total output RF power from the transmitter and would be the same value that is displayed on the Main LCD menu. This is represented as a percentage of the full rated output power of the transmitter.
31C1936 CONTROLLER BOARD 3.2.2 L/O Status LED VSWR Lockout Status • Lit when the system has seen three VSWR trips in under 1 minute. When a VSWR trip occurs, the MXi controller will reset the trip automatically and repower the RF amplifier. If three trips occur within 1 minute, the Lockout status is set and the RF amplifier will remain OFF. The Lockout status can be reset by the operator using LCD touchpad, front panel reset button or a remote reset command.
31C1936 CONTROLLER BOARD If the amplifier is ON, then the output power telemetry cannot fall more than 160 mV under the AGC reference level. That is if the AGC is set for 100% power (voltage of 4.0v), then the AMP1 LED will be lit only if the output power telemetry is higher than 3.84v (or 92 % power). Note that the output power is proportional to the square of the telemetry voltage.
31C1936 CONTROLLER BOARD mean that the actual reject power must be 1/64th of the combined forward power for the status to be true. This would translate into having reject power lower than about –18db than the forward power. The forward power must be greater than 10% for this status to be calculated since at low combined forward powers the reject power measures will most often just read zero and be meaningless.
31C1936 CONTROLLER BOARD level. This allows the operator to adjust the phasing and reduce the reject power to a level lower than 1%. A reject level of around –30db is typical. The last two readings of the second line are the hexadecimal values sent to the two CPU D/A converters respectively. The range of these values are from $00 to $FF where $FF is equivalent to decimal 255. These values are provided to indicate to the operator when the DAC level has reached either the lowest or highest limit. 3.3.
31C1936 CONTROLLER BOARD 3.3.5 PSOK Status LED Power Supply OK status, the 50V power supply to the RF amplifier is currently ON and is operating properly. • Lit when the Power Supply is ON. The P/S voltage, current and status are all OK. • Not lit when the Power Supply is either OFF or has some operational problems. 3.3.6 AMP1 Status LED Status that indicates the condition of RF amplifier #1. The amplifier(s) report their operating parameters to the central control unit via a RS232 serial stream.
31C1936 CONTROLLER BOARD • Not lit when Comms is lost, RF power is low or either Thermal Intk is open or a VSWR Lockout has occurred. 3.3.8 PHASE Status LED Status that shows if the reject power is sufficiently lower than the combined forward power. When the transmitter is turned ON, both amplifiers should be generating RF power. The main controller has phasing circuitry that allows these two amplifier outputs to be combined through a 2-way combiner to the RF output.
31C1936 CONTROLLER BOARD 3.4 AMPLIFIER1 (AMPLIFIER2) SCREEN The RF Amplifier submenu is entered by pressing the AMP1 (or AMP2) submenu button on the main LCD screen. This submenu displays all the various power, status and controls for the RF amplifier. Each display item and control is described as to its meaning and function. The AMP1 and the AMP2 submenus are identical except the first button on line four of the LCD display will denote ‘Amp2 VRST’ when the Amp2 screen is being accessed.
31C1936 CONTROLLER BOARD only receive a level of 0 to 5VDC. To satisfy this requirement, the hardware circuitry divides the actual AGC control voltage by two and displays this half value on the LCD. The second item of the second line shows the telemetry of the Cutback voltage that the MXi controller uses to reduce the power generated by the RF amplifier in the presence of reflected power (VSWR condition).
31C1936 CONTROLLER BOARD 3.4.1 TRIP Status LED VSWR Trip Status • Lit when the system has seen at least one VSWR trip, can be reset by operator using LCD touchpad. • Not lit when there have been no VSWR trips since the last time this was cleared. Note that this does not mean that there is a current VSWR trip but that one did occur. The operator may have this status as true (with no Lockout status) and still have the RF amplifier active. 3.4.
C1936 CONTROLLER BOARD 3.4.6 FAN2 Status LED Status that shows if FAN2 is currently operational. When the transmitter is turned ON, all the fans are turned on. • Lit when fan rotational status is true, this only happens if the fan is actually rotating. • Not lit when the fan is not rotating; if the other fans are OK, this indicates a failure. 3.4.7 FAN3 Status LED Status that shows if FAN3 is currently operational. When the transmitter is turned ON, all the fans are turned on.
31C1936 CONTROLLER BOARD Figure 10 Power Supply Submenu Screen The first line gives the measured telemetry values for the power supply voltage and current for the +50V power output. The second line gives the power supply state, which can have three possibilities: ACTIVE (operating normally), OFF NORMAL (turned off by operator) or OFF TRIPPED (off due to an error). Note: if the power supply is OFF, there will be no voltage or current telemetries.
31C1936 CONTROLLER BOARD 3.5.5 SubMenu Select Buttons The fourth line of the LCD has a label ‘PS1 on AMP1’ and ‘PS2 on AMP2’ that has no control function but is only displayed to indicate which values are associated with PS1 and PS2. There is only one menu button selection for the Power supply menu and that is the rightmost button labeled OUT which exits this submenu. When the operator is finished in the submenu, an OUT command returns to the Main LCD screen. • OUT = Returns LCD to the main LCD Screen.
31C1936 CONTROLLER BOARD 3.7 COMBINED INTERLOCKS SCREEN The Combined Interlocks submenu is entered by pressing the INTK submenu button on the main LCD screen. This submenu displays all the various interlocks for the RF amplifier. Each display item and control is described as to its meaning and function. The LCD displays a typical INTK submenu as follows: Figure 12 Transmitter On, Interlocks OK Screen The first line of the LCD shows the transmitter ON/OFF status and the resulting interlock status.
31C1936 CONTROLLER BOARD 3.7.3 TRIP Status LED VSWR Trip Status • Lit when there have been no VSWR trips since the last time this was cleared. • Not lit when the system has seen at least one VSWR trip. Note that this does not mean that there is a current VSWR trip but that one did occur. The operator may have this status as true (with no Lockout status) and still have the RF amplifier active. This can be reset by the operator using the LCD touchpad button RST or by the front panel Reset button. 3.7.
31C1936 CONTROLLER BOARD 3.7.8 SubMenu Select Buttons The fourth line of the LCD has four button selections which are available to the user. Two buttons select the amplifier interlock submenus, one button is for VSWR reset and the last exits this menu. • AMP1 = Selects the Amplifier1 Interlock Submenu LCD Screen. • AMP2 = Selects the Amplifier2 Interlock Submenu LCD Screen • RST = Resets the VSWR trips (on the main controller and both amplifiers). • OUT = Returns LCD to the main LCD Screen. 3.
31C1936 CONTROLLER BOARD • Not lit when the system has seen at least one VSWR trip. Note that this does not mean that there is a current VSWR trip but that one did occur. The operator may have this status as true (with no Lockout status) and still have the RF amplifier active. This can be reset by the operator using the LCD touchpad button RST or by the front panel Reset button. 3.8.2 L/O Status LED VSWR Lockout Status • Lit when there is no VSWR Lockout condition.
31C1936 CONTROLLER BOARD • Not lit when the Power Supply is either OFF or has some operational problems. If the Power Supply has indeed been set to ON and the front panel ON LED is lit, an error is present. 3.8.7 Cutback Status LED Status that shows if the amplifier is not in cutback mode.
31C1936 CONTROLLER BOARD 3.9 REMOTE CONTROLS AND RS232 SERIAL SCREEN The Remote Control submenu is entered by pressing the RCtl submenu button on the main LCD screen. This submenu displays all the various parameters that affect the remote controls and the remote RS232 status communications stream. The LCD displays a typical RCtl submenu as follows: Figure 14 Remote Control Submenu The first line of the LCD shows three parameters that can assist the operator in checking remote RS232 serial operations.
31C1936 CONTROLLER BOARD The third line of the display has a number of status lights with a legend describing the particular status underneath and all enclosed in a dashed line box. When the light is fully darkened, it indicates that this particular status is true or active. When the light is hollow, it indicates that this particular status is false and inactive. Each status is detailed as follows. 3.9.1 Remote The operator has the option of allowing remote commands or disabling them.
31C1936 CONTROLLER BOARD 3.9.5 Error Serial Input Stream Error The external computer will send a four-byte serial stream of a specific format to ask for a certain action to be taken. The MXi monitors the format of this four-byte serial stream and sets the Error status if the stream has the wrong format. This is useful in determining if there is a serial transmission problem between the external computer and the MXi. This bit can be cleared by the CLR menu button on the LCD.
31C1936 CONTROLLER BOARD 3.10 GENERAL SCREEN The General submenu is entered by pressing the GEN submenu button on the main LCD screen. This submenu displays all the configuration and setup information of the particular model of MXi transmitter. The first line displays the transmitter type, the second line displays the software code and revision, the third line displays the LARCAN ID number that is used in the factory to determine options, date the boards were made and other information.
31C1936 CONTROLLER BOARD The first five buttons from the left allow the operator to set a new time or date for the system. The user can set the Year, Month and Day of the date portion. The system will automatically adjust the DoW (day of week) depending on the date set. The operator can set the Hour and Minute of the time but seconds will be set to zero so if a person wants to calibrate to the second then if the current time is 11:40.22 then set the time for 11:41.
31C1936 CONTROLLER BOARD • Inet On = Internet interface is active and will respond to external requests [factory setting] • NewIP = Operator has changed (but not yet saved) and new IP address • NewMask = Operator has changed (but not yet saved) and new IP Mask address • Active = The internet is currently receiving or transmitting data • RxD = Data is being received • TxD = Data is being transmitted 3.11.
31C1936 CONTROLLER BOARD 4 SETUP PROCEDURES The following sections detail the various set up procedures for the MXi transmitter system. These procedures should only be done by qualified personnel. If the calibrations and setups are done improperly, it can result in the transmitter being prone to damage. The transmitter is normally set up in the factory for the particular operating power required when first installed.
31C1936 CONTROLLER BOARD 3. Turn up the drive level until the output power measures the desired reading. Do not use the meter of the transmitter itself to determine output power, since at this point it may be uncalibrated. Also check the reject power voltage at R68. This voltage should be less than .50 volts which represents a reject power of around 6%.
31C1936 CONTROLLER BOARD 4.1.5 Calibrate Reflected Power Level 1. The reflected power is a special case and needs to be calibrated by feeding a known voltage to the MXi control board reflected power DC sample input. This is due to the fact that it is difficult to set up an actual VSWR condition that is both accurate and safe for the amplifier in the manner that it is done at the factory. 2. To calibrate the reflected power, install jumper E3 that prevents any VSWR trips. 3.
31C1936 CONTROLLER BOARD proceed to phasing. Both Amps should have similar output power levels (one should not be more than 10% higher or lower then the other). Adjust rear panel pots R84 and R96 until the reject power is minimized. The LCD provides Reject power in percent and in –db down from maximum forward power. The percentage power will indicate a value greater than zero whenever the reject power is over –22db. Once below this level the operator can fine tune the phasing by watching the –db indicator.
31C1936 CONTROLLER BOARD section where the stop bits will be either 1S or 2S in this string. At the same time, the NewFmt light on the third line lights to indicate that a new serial format (Baud or Stop bits or both) is pending but not taken. Once the operator is satisfied with the new Baud and Stop bits, pressing the SAVE button causes the MXi to implement the new serial format. Pressing the CLR button abandons all selections and revert to the previous Baud and Stop bits without any action taken. 4.
31C1936 CONTROLLER BOARD 1. To set up the voltage reading, turn on the transmitter and verify that both power supplies are indeed running. 2. With a voltmeter, measure the actual voltage from the power supply for Amp1. Looking from the front of the MXI, the AMP1 power supply is located on the right side of the chassis. The power supply voltage can be measure directly on the power supply lugs or at R22 of the control board.
31C1936 CONTROLLER BOARD 5 REMOTE CONTROL CONNECTIONS MXI TRANSMITTER On the rear of the main Controller Chassis, the remote control connections are available on a 15-pin male D-shell connector J5 of pc board 31C1936. This includes all of the remote controls, status and telemetries available to the operator for combined operations. The signal designations for each pin of J5 can be viewed on sheet 5 of the schematic in Figure 29.
31C1936 CONTROLLER BOARD TX D-Connector (J5) Designation Description Pin 4 RC_TX_On Turns Transmitter ON Pin 5 RC_TX_Off Turns Transmitter OFF Pin 6 RC_Reset Resets VSWR Trips Pin 7 RC_AGC+ AGC (Power) Raise Pin 8 RC_AGC- AGC (Power) Lower Pin 15 Ground Ground Reference 5.1.1 RC_TX_On Remote Transmitter ON Control The MXi controller has the facility to force the ON/OFF function to follow the front panel ON button.
31C1936 CONTROLLER BOARD If jumper E2 is removed (this is the normal mode), the reset command is fed only to the CPU chip, which then issues a VSWR reset command to relay K1, only if the MXi system is in Remote Mode. If jumper E2 is installed, the external remote reset command is manually routed to the VSWR relay reset coil and effectively bypasses the CPU chip. In this configuration, a remote reset command clears the VSWR relay and does not depend on the MXi being in Remote Mode.
31C1936 CONTROLLER BOARD The MXi amplifier unit uses an onboard DAC (D/A Converter) to provide a reference level of where the operator wishes the output power to be set to. It will compare the actual detected power level to this reference level and then generate an attenuation signal to the RF front end amplifier to achieve this desired power level. The AGC- lower control will decrease the reference level of the main controller in steps of around 1-2 %.
31C1936 CONTROLLER BOARD TX D-Connector (J5) Designation Description Pin 10 RS_Remote Tx is in Remote Mode Pin 11 RS_Err Tx has an error Pin 12 RS TXOn Tx is turned ON Pin 13 RS VTrip VSWR Trip Occurred Pin 14 RS_VLock Tx is OFF due to VSWR Pin 15 Ground Ground Reference 5.4 COMBINED TELEMETRY OUTPUTS These are buffered OpAmp outputs, out of quad pack LM324 operational amplifiers. The available output voltage is limited to the range of 0 – 5VDC.
31C1936 CONTROLLER BOARD TX D-Connector PC Board Connector Designation Description Pin 1 J6 Pin 1 RC_TX_On Turns Transmitter ON Pin 9 J6 Pin 2 RC_TX_Off Turns Transmitter OFF Pin 2 J6 Pin 3 RC_Reset Resets VSWR Trip Pin 4 J6 Pin 7 RC_VOR VOR On Controls Pin 12 J6 Pin 8 Ground Ground Reference Pin 15 J6 Pin 14 EXT1+ Secondary Ext1 Intk Pin 8 J6 Pin 15 EXT1– Secondary Ext1 Intk TX D-Connector PC Board Connector Designation Description Pin 10 J6 Pin 4 RS_Remote Amp is in
31C1936 CONTROLLER BOARD 6 CIRCUIT DESCRIPTIONS 6.1 M9S12E128 MICROPROCESSOR The Motorola M9S12E128 microprocessor (often referred to as the CPU or HC12) performs all of the control interface and communications in the MXi transmitter system. It is a 44-pin surface mount PLCC type device that is permanently soldered to the circuit board and is not field serviceable or easily replaced without special surface mount tooling. A brief description of the part is given in this.
31C1936 CONTROLLER BOARD PAD13 Output Remote Status: Tx ON PAD14 Output Remote Status: VSWR Trip PAD15 Output Remote Status: Remote Mode PORT E Misc Functions PE0 Input Remote Control: TxOn Command PE1 Input IRQ: From Spi UART PE4 Output LED: Phaser Adjusted PE7 Input Crystal Select [fixed] PORT M Serial Comms, DAC, I/O PM0 Output DAC0: Phaser #2 Control PM1 Output DAC1: Phaser #1 Control PM3 Output PHASER: Control Select PM4 Input SCI2: RxData PM5 Output SCI2: TxData PM
31C1936 CONTROLLER BOARD PORT S Serial Comms, SPI, XPortCtl PS0 Input SCI0: RxData PS1 Output SCI0: TxData PS2 Input SCI1: RxData PS3 Output SCI1: TxData PS4 Input SPI: MISO PS5 Output SPI: MOSI PS6 Output SPI: SCLK PS7 Output XPORT: Reset Control PORT T Misc Functions PT0 Input PS1 On Status PT1 Input PS2 On Status PT2 Input Phaser Control Status PT3 Output CPU: TxON Command PT4 Input LED: General PT5 Output LED: General PT6 Output LED: General PT7 Output
31C1936 CONTROLLER BOARD The microprocessor uses +5 volts as a power source that is derived from the +12 volts input provided by the two DC power supplies. The two +50 volt power supplies have an auxiliary +12 volt output rated at 3 Amp each to run the control circuitry of the main board. These +12 volt outputs are always active from the DC power supplies even when the +50 volt output is not activated. The main controller board diode-Ors these two +12 volt inputs into a single supply at around +11.
31C1936 CONTROLLER BOARD The second and third SCI serial ports designated as SCI1 and SCI2 are allocated to communicating with external amplifiers Amp1 and Amp2 respectively. The circuit for each of these amplifiers are identical and so only Amp1 will be described here. Each amplifier has its own microprocessor that serially communicates with the main controller. This interface receives commands from the main controller and reports back the amplifier operating parameters for display on the LCD.
31C1936 CONTROLLER BOARD 6.2 IIC REAL TIME CLOCK For the following description, refer to Figure 25 (Sheet #1 of the Schematic) in the upper section of the drawing for the IIC real time clock circuitry. This DS1307 is a National SemiConductor device that provides independent timekeeping for the main CPU chip to timestamp its' LOG entries. The interface between the device and the CPU consists of a two wire synchronous data stream that consists of a DATA line and a CLOCK line.
31C1936 CONTROLLER BOARD device. The SPI Uart then uses standard TTL transmit data (TxD) and receive data (RxD) to forward the system data stream onto the Xport device. Hardware handshaking lines Request to Send (RTS) and Clear to Send (CTS) are used to control the data flow between the Uart and the Xport. 6.4.2 External Interface The Xport device receives the serial data stream from the SPI Uart, which in turn receives the data stream from the main CPU.
31C1936 CONTROLLER BOARD (31C1897). The reason for the dual monitoring is that in the case where an individual amplifier cannot communicate serially with the main Controller, the MXi can view its own internal power supply monitoring to determine if the power supply is ON and operating in a reasonable range. The voltage and current monitoring done by the main MXi Controller board is used for error processing such as overcurrent and power supply OK status as displayed on the LCD.
31C1936 CONTROLLER BOARD main Controller. This calibrated voltage is buffered by OpAmp U34A which sends this voltage to test point TP3 and also to the A/D input of the CPU chip U1. 6.5.3 Voltage Metering The Power Supply voltage is expected to be +50 volt DC +/- 0.5V and is fed into the MXi board from one connector J11 for P/S #1 (for Amplifier #1) and connector J12 for P/S #2 (for Amplifier #2).
31C1936 CONTROLLER BOARD D/A converter. The same zener output signal is also sent to buffer OpAmp U26A that provides a low impedance telemetry output for the Remote Control connector J5. The circuitry for the reflected and reject powers are virtually identical to that of the forward power described above except that the OpAmp gain for the reflected power input is 3.0 instead of 1.1 since the level of the reflected power is typically much lower than either the forward and reflected power.
31C1936 CONTROLLER BOARD remains constant, regardless of the picture content of the transmission. Measurement occurs during the back porch. Both sections of the board are configured in a similar way. 6.7.3 VSWR Protection Circuitry The board is fitted with two RF detectors, which respond to RF samples fed from RF directional couplers mounted on output combiner of the Amplifier heatsink.
31C1936 CONTROLLER BOARD Two poles are connected in parallel and send +12V (or +24 volts in some applications) to the fans at connector J8. Two poles are used since the current rating of one relay pole is not sufficient for the total current draw of up to four fans. One pole is used to send a +12V command to the +32V power supply. This command causes the power supply to activate and send its +50V to the RF amplifier.
31C1936 CONTROLLER BOARD The output of the phase adjusting stage passes through a fixed pad R91, R87, R92 (R111, R107, R112) which provides some isolation for the phase adjuster and provides a match for the subsequent amplifier. U28 and U31 are Mini-Circuits RF amplifier IC device type GALI-6F, designed to operate from +8V to +12V. These operate Class A, thus are constant current supplied and are fed from the system +12V through dropping resistor R83 (R104).
31C1936 CONTROLLER BOARD Figure 24 MXi Controller Board Assembly Diagram 31C1936A1 Rev 1.0 PUB11-21 Rev.
31C1936 CONTROLLER BOARD Figure 25 MXi Controller Board Schematic 31C1936 sht1 Rev 1.0 PUB11-21 Rev.
31C1936 CONTROLLER BOARD Figure 26 MXi Controller Board Schematic 31C1936 sht2 Rev 1.0 PUB11-21 Rev.
31C1936 CONTROLLER BOARD Figure 27 MXi Controller Board Schematic 31C1936 sht3 Rev 1.0 PUB11-21 Rev.
31C1936 CONTROLLER BOARD Figure 28 MXi Controller Board Schematic 31C1936 sht4 Rev 1.0 PUB11-21 Rev.
31C1936 CONTROLLER BOARD Figure 29 MXi Controller Board Schematic 31C1936 sht5 Rev 1.0 PUB11-21 Rev.
31C1936 CONTROLLER BOARD Figure 30 MXi Front Panel Interface Board Assembly 21B2537A1 and Schematic 21B2537S1 PUB11-21 Rev.
31C1936 CONTROLLER BOARD NOTES PUB11-21 Rev. 0 July 9, 2011 11-21-73 MXi802U Controller Board Rev.