G021
CONTROL UNIT

  

  

The G021 CONTROL LOGIC manages the transmitter functioning and makes available the information on its functioning status to the operator. The unit is self-contained and arranged into a 19 inchs frame designed in order to tolerate mechanical stresses. The central processing unit is based on a H8/3003 microprocessor (16 MHz clock) that can be considered like a Master of the distribuited control system. The information is displayed on a graphic LCD display and is recalled by means of a numeric keyboard (F1 to F6). Four programming pushbuttons (START, STOP, LOCAL, REMOTE) allow to switch-on/to stop the transmitter and to set the functioning mode. The managing is performed via a POLLING software which tests three peripheral assemblies located in the DETECTORS/INTER- FACE group for Driver section, and in the HV LEVEL POWER SUPPLIES and FOCUS POWER SUPPLY . I.O.T. DETECTOR, for the RF Power Amplifier section. The peripheral assemblies are identical and D.A.I. type (Data Acquisition Interface). The D.A.I. are pre-programmed units, provided with microprocessor; each of them allows to manage 8 digital inputs, 8 digital outputs (by means of opto.isolators) and 8 A/D converter lines with 12 bit resolution and input voltage range from -5 V to +5 V. The peripheral assembly located in the HV LEVEL POWER SUPPLIES also allows the managing of a double digital/analog converter needed for trimming the grid and filament voltages. Each peripheral assembly has a HW address and is connected to a local acquisition assembly (within the G021) via an optical plastic wire. Data rate allowed is up to 40 kBaud. In order to save the transmitter, if any fault occurs to the optical fiber, the slave unit also stops the subassemblies monitored if no data confirmation is riceved from the G021, at the same time the G021 starts the stop procedure for the transmitter. The local acquisition assembly D.L.I. (Data Local Interface) receives the information coming from the outside and sends it to the CPU.16 MASTER, where the transmitter managing program is stored. Any fault in a D.A.I. peripheral assembly is displayed as an error indication on the graphic display; the indication is "ERROR PERIPHERAL No. ....." If this occurs, the G021 stops the transmitter. A reset procedure is also memorized in order to restart the transmitter. The transmitter functioning can be restored by means of the RESET function in the PROGRAM menu or the RESET function of the SYSTEM STATUS menu in the TUBE MEASURES menu.

 

The G021 manages four different types of alarms:
  • PROTECTION alarms;

  • TUBE COOLING alarms;

  • VACUUM TUBE ELECTRODES alarms;

  •  SPECIAL alarms.

When one or more of these alarms occurs, the G021 stops the transmitter and cut.off the power supply to the vacuum tube electrodes. If these alarms disappear the switching.on procedure of the transmitter is restarted. The reoccurring of these alarms up to 3 times causes the final stop of the transmitter and the storage in the .HISTORY. table (time and date are also stored); the G021 displays the .ALARM TUBE . PRESENT.. The transmitter can be restarted only if the RESET pushbutton has been depressed.

The PROTECTION alarms are the following:

  • Smoke Alarm

  • Body current High

  • Dummy load Alarm

  • Main Fault

  • Internal Interlock

  • External Interlock

  • Cavity Disconnected

The TUBE COOLING alarms are the following:

  • Total Cooling fault

  • Rack blower fault

  • Motor blower fault

  • Temp. cavity fault

  • Pressure cavity fault

  • Water temp.in fault

  • Water temp.out fault

  • Air/water flow fault

The first three alarms are checked after the START pushbutton has been depressed and, if they are present, the G021 do not allows the switching.on procedure to start. The others alarms are processed after the warming.up period and stop the switching.on proce- dure if they are not within the steady state. At the end of the switching.on procedure, if one or more of these alarms occur, causes a .FAULT COOLING. storage which is displayed in the .HISTORY. table (time and date are also stored).

The VACUUM TUBE ELECTRODES alarms are the following:

  • ION pump

  • Control grid

  • Focus (solenoid)

  • Filament

  • Beam

  • I.O.T. tube driver

The G021 manages each power supply of the I.O.T. tube (thru a D.A.I. ass.y) by sending the sequential "START" controls; the first electrode to be supplied is the "CONTROL GRID", the last is the "DRIVER".
Only the ION PUMP is always enabled. After the sending of the "START" control, the G021 checks the "READY" signal of each power supply and the values of the I.O.T. tube voltages and currents. Even if only one "NOT READY" or "FAULT" signalling occurs, the G021 stops the switching.on procedure up to the faulty power supply and sends the "STOP" controls for all the power supplies which follow the faulty one.
I.E.: a fault in the FILAMENT power supply causes the stop of the I.O.T. TUBE DRIVER, BEAM and FILAMENT power supplies. Each fault of the I.O.T. tube electrodes is stored in the "HISTORY" table.

The SPECIAL alarms are the following:

  • Beam overcurrent 

  • Current spike of the beam

  • VSWR high

  • ARC Cavity

If an overcurrent occurs, the G021 disables the .START. control for the BEAM and the I.O.T. TUBE DRIVER within 100 msec. The power supply is fed again to the BEAM after 5 sec. Regarding the CURRENT SPIKE of the BEAM, it is important to note that the Crowbar Control Unit disables the BEAM power supply within 20 sec., but at any rate the G021 operates a confirma- tion of the disabling for the BEAM power supply, after 10 msec. from the faulty event. In this case the G021 displays a .DISCHARGE CROWBAR. indication along with a .NOT READY. indication for the Crowbar Control Unit as long as the control device (thyratron) in the crowbar system, is not reset for correct functioning. Regarding the VSWR HIGH alarm, it causes a stop of the power supply both for the I.O.T. TUBE DRIVER and for the BEAM, as long as it lasts. The intervention time of the G021 is practically immediate and prevents any damage for the driver.

 



G042 CONTROL LOGIC
Functional Description

 

Data Acquisition Interface (D.A.I.)

The peripheral Data Acquisition Interface assembly is carried out on eurocard dimension (100x160) PCB. The SMD technology is used for assembling part of components; the PCB is multi-layer (6 layers) and treating against high voltage discharge is employed. The voltages power supply needed for differential amplifers are �t�12 V and a +5 V voltage is required for the CPU power supply (200 mA max.); all of the circuits under high voltage have a galvanic insulation. Telesignals and telecontrols are available outside on a STRIP connector (64 pins). The serial communication interface is carried out by means of bipolar optical fibers with Tx and Rx units working at 40 kBaud rate. The optical fibers employed are plastic type which allow connections up to 20 m.
HW addressing is performed by means of dip-switches.

The peripheral Data Acquisition Interface assembly also has the following features:

  • microprocessor 87C654

  • 8 A/D converter lines MAX180 (12 bit resolution+sign), each of them provided of filter, protection against voltage spikes up to

  • 500 Vrms, analogical input range from +5 V to .5 V with differential amplifiers at the input;

  • 8 digital input lines with optoisolator (the power supply for the output section is separated);

  • 8 digital output lines with optoisolator;

  • WATCH-DOG section MAX690 which can be by-passed by means of jumper;

  • two 8.bit D/A converters PCF8594 which are able to feed a voltage from 0 to +5 V;

  • dip switches for address setting (4 dip);

  • high speed U.A.R.T. section.


Data Local Interface (D.L.I.)

The peripheral Data Local Interface assembly is carried out on eurocard dimension (100x160) PCB.

The Data Local Interface features are:

  • microprocessor 87C654 .MAX 690 Watch dog supervisory

  • FIFO buffer for serial communication and communication with bus

  • high speed U.A.R.T. section

  • dip switches for address setting (4 dip)


Security features for telecontrol

An high grade of security has been achieved for this telecontrol system which allows the manag- ing of several peripheral units located in dangerous areas for personnel. This is done by means of hardware and software protections as follows:

  • it is possible to send a numerical datum from the CPU-16 control ass.y to the D/A converter of
    the D.A.I. 1 remote ass.y  (Vf Adj.).
  • it is possible to regulate the D/A converter voltage of the D.A.I. 1 remote ass.y  (Vg Adj.)
    The above regulations allow the personnel to operate with low level voltages which in their turn
    affect the grid and filament power supplies (-30 kV).
  • any fault of a peripheral unit is sent in real time to the D.L.I. (CPU-16) (i.e.: disconnection of the
    optical cable) in such a way the HALT condition is set on the peripheral unit (every output is open and
    the output voltages of the D/A converters are equal to 0).
  • any fault of the CPU.16 (i.e.: the WATCH-DOG triggering which causes the RESET or any other
    causes which break the communication between the CPU.16 and the D.L.I.) are send in real time
    from the D.L.I. to the peripheral. The D.L.I. is checked by the CPU.16 within a preset timeout, out of
    this time interval the HALT condition has started.
  • the peripheral checked by the CPU.16 sends its response in real time in such a way the
    CPU.16 can operate to prevent any failure. The HALT condition causes the stop of the system.