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Optimized MASS device for synchronous measurements with Paranal DIMM Electronics and Device control
Kornilov V., Shatsky N., Shugarov A., Voziakova O. Decemb er 4, 2003


Contents
1 Electronics overview 1.1 Common characteristics of electronics and 1.2 Detectors unit . . . . . . . . . . . . . . . . 1.3 Auxiliary electronics . . . . . . . . . . . . 1.4 Star centering unit . . . . . . . . . . . . . 1.5 Requirements to p ower supply . . . . . . . 1.6 Data exchange proto col (physical level) . 1.7 RS485/LPT converter . . . . . . . . . . . 2 Electronic mo dules 2.1 Detectors unit . . . . . 2.2 Bicounter mo dule . . . 2.3 Auxiliary mo dule . . . 2.4 Stepp er motor mo dule 2.5 Connections . . . . . . 2.6 RS485/LPT converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 6 6 8 8 9 10 11 12 12 12 19 22 22 24 29 29 30 32 35 36

RS-485 .... .... .... .... .... .... . . . . . . . . . . . . . . . . . . . . . . . .

line ... ... ... ... ... ... . . . . . . . . . . . . . . . . . .

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3 Microprogramming and Instructions set 3.1 Logical level of interaction b etween computer 3.2 Bicounter mo dule . . . . . . . . . . . . . . . . 3.3 Auxiliary mo dule . . . . . . . . . . . . . . . . 3.4 Stepp er motor controller mo dule . . . . . . . 3.5 Up dating a micro co de . . . . . . . . . . . . .

and .. .. .. ..

mo .. .. .. ..

dules ... ... ... ...

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List of Figures
1.1 1.2 1.3 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 2.10 2.11 2.12 2.13 2.14 2.15 Schematic view of electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Principles of the centering unit function . . . . . . . . . . . . . . . . . . . . . . . Illustration of data exchange b etween host computer and mo dules. . . . . . . . . Circuit diagram of the Detectors unit electronics. . . . . . . . . . . . . . . . . . . Circuit diagram of the analog part of the Bicounter mo dule electronics . . . . . . Circuit diagram of the digital part of the Bicounter mo dule electronics . . . . . . Placement of the comp onents on the PCB of the PMT voltage divider . . . . . . Placement of the comp onents on the PCB of the Pulse amplifier and discriminator Placement of the comp onents on the PCB of the digital part of the Bicounter. . Circuit diagram of the main part of the auxiliary electronics. . . . . . . . . . . . Placement of the comp onents on the PCB02A of the auxiliary electronics. . . . . Circuit diagrams of the separate parts of the auxiliary electronics . . . . . . . . . Placement of the comp onents on the PCB02C and PCB02D of the auxiliary electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Circuit diagram of the stepp er motor controller electronics. . . . . . . . . . . . . Placement of the comp onents of the stepp er motor controller electronics. . . . . . Connections b etween the separate b oards of the device . . . . . . . . . . . . . . . Printed circuit b oards for the RS485/LPT . . . . . . . . . . . . . . . . . . . . . . Circuit diagram of the RS485/LPT converter. . . . . . . . . . . . . . . . . . . . 7 9 10 14 15 16 17 18 18 20 21 21 22 23 25 26 27 28

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List of Tables
2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 3.1 Sp ecification for Sp ecification for Sp ecification for Sp ecification for Sp ecification for Bus colors table Arrangement of Sp ecification for detectors unit electronics. . . . . . . . . an analog part of the Bicounter mo dule. a digital part of the Bicounter mo dule. the Auxiliary electronics. . . . . . . . . the Stepp er motor mo dule. . . . . . . . ....................... line cable . . . . . . . . . . . . . . . . . the RS485/LPT converter (see SCH02). .. . .. .. .. .. .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 13 17 19 24 24 25 27 29

Used signal bytes.

...................................

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Bibliography
[1] Kornilov V., The optimization of MASS device for synchronous measurement with Paranal DIMM. A Prop osal to Europ ean Southern Observatory (ESO). Decemb er 11, 2002 [2] Kornilov V., Potanin S., Shatsky N., Voziakova O., Zaitsev A. Multi-Aperture Scintil lation Sensor (MASS). Final design report. February 2002. [3] Kornilov V., Potanin S., Shatsky N., Voziakova O., Shugarov A. Multi-Aperture Scintil lation Sensor (MASS) Upgrade. Final report. January 2003. [4] Kornilov V., Shatsky N., Voziakova O., The optimization of MASS device for synchronous measurement with Paranal DIMM. First stage project report April 2003. [5] Kornilov V., Tokovinin A., Voziakova O., Zaitsev A., Shatsky N., Potanin S., Sarazin M. MASS: a monitor of the vertical turbulence distribution. Pro c. SPIE, V. 4839, p. 837-845, 2003 [6] A.Tokovinin, V.Kornilov, N.Shatsky, O.Voziakova, Restoration of turbulence profile from scintil lation indices, MNRAS 2003, V. 343, P. 891

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Intro duction
The do cument presents description of the electronic mo dules of the optimized MASS device. The base of the electronics design is the same as in original MASS: mo dular structure, data exchange via RS-485 interface, PMTs as light detectors. Meanwhile, the real electronics were significantly redesigned: numb er of separate mo dules was reduced from 7 (in original MASS [2]) to 3 in the current design. First Chapter of this do cument contains general description of the electronics as well as overview of data exchange proto col b etween the device and PC. Detailed design of the MASS electronic mo dules (circuit diagrams, printed circuit b oard views, their sp ecifications) is provided in the second Chapter. Although the description of RS485/LPT converter is available in [3], this information is included in the do cument also. Last Chapter contains detailed description of the low level command set, which can b e used during handling of non-standard situations, which can arise in test, adjustment or repair pro cess. The description of the micro co de up date pro cedure is presented, to o. The do cument contains the detailed information on MASS device, which may b e needed in case of device malfunctions or fault. The information will b e useful for exact understanding of the device p ossibilities and p otentials.

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Chapter 1

Electronics overview
The MASS electronics inherits the mo dular principle of the original MASS device; the photometric mo dules were united in one detectors unit, some functions of other mo dules were redistributed due to partial mo dification of the device construction. In order to promote the device reliability, the numb er of external and inter-PCB connectors was minimized. The basic Atmel AVR micro controller mo del was changed from AT90S2313 to more p owerful and advanced ATMega8, meanwhile the communication proto col of data transfer from MASS to PC was retained unchanged to maintain the software compatibility with the original MASS system.

1.1

Common characteristics of electronics and RS-485 line

As in original design, the architecture of all MASS electronic mo dules is similar. The kernel of any mo dule is an AVR micro-controller ATMega8 from Atmel company running at 14.746 MHz frequency. In principle, such a clo ck frequency provides the standard transmitting rate as large as 1840 Kbit/sec instead of 460.8 Kbit/sec in original MASS. A big merit of these controllers is the p ossibility of their re-programming using the data exchange line. All mo dules are designed to supp ort this p ossibility. Schematic view of the MASS electronics is presented in Fig. 1.1. All information exchange b etween the host computer and the individual mo dules is executed via RS-485 line working in half-duplex mo de. The line connects to LPT p ort of PC via a sp ecial RS485/LPT converter. A pure RS-485 interface is used in the segment "host computer -- MASS". Balanced data lines A and B are prop erly terminated and biased from b oth ends of the long cable to provide safefault data transmission. For inter-communication b etween the electronic mo dules, RS-485 itself and 2 additional lines are used. These additional lines do not have constant sp ecification and are used to transmit sp ecific lo cal signals: SYNCHRO -- for common hardware synchronization of the mo dules, and OVERLIGHT -- for fast hardware protection of PMTs against light overflow.

1.2

Detectors unit

MASS detectors must measure the intensity of light in four channels synchronously with a very short (1 ms) exp osure time and high duty cycle. The numb er of photons detected in an elementary exp osure in each area go es up to tens of thousand dep ending on the channel and star brightness. Preliminary investigation shows that most suitable PMT is bi-alkali Hamamatsu 6


1
High voltage

2
Overlight Synchronization

3

Detectors module 1

Detectors module 2

Auxiliary electronics

Illumination, control light, sensor, centering unit

RS485 serial bus

Computer

Converter RS485/LPT Power +12 DC

Figure 1.1: Schematic view of electronics for MASS device. 1 -- detectors unit, 2 -- electronics b ox, 3 -- electronic elements in main MASS case. Centering mo dule connects with RS-485 line via auxiliary electronics R7400P (see Rep ort [4]). It has a low dark current (< 100 pulse/s), high sensitivity in blue-green sp ectral region, suitable temp oral characteristics and very compact size. Contrary to original MASS, where the detectors were implemented as four separate photometric mo dules (PMs), four MASS device detectors are united in one detector unit, including b oth PMTs and the asso ciated electronics. Detector electronics is sub divided in two indep endent two-channel mo dules (further -- Bicounter mo dule). Nevertheless, these mo dules are placed at one PCB, which p ermits to diminish a numb er of inter-connections. Each bicounter consists of two voltage dividers for PMT, two very fast amplifier- discriminators, two counters driven by a single micro-controller and an interface circuit. Both data from the mo dule to a host computer and commands from a computer to the mo dule are transmitted via RS-485 line. Interaction b etween PM and computer is describ ed in Section 1.6. Besides, an additional line connects the photometric (bicounter) and p ower supply mo dules and immediately shuts down the HV when the PMT flux exceeds the maximum rating. This feature assures the safety of PMTs. The bicounter mo dule executes the following functional commands: set level of the pulse discrimination, run series of micro exp osures with a preset exp osures numb er and integration time, set needed integration time or work by external synchro, set length of series, and so on. Data packet from bicounter contains always counts from b oth PMT. Physically, the detector unit is attached to the electronics b ox and they can b e removed from the MASS device together. Therefore, electrical connections b etween these b oth units are soldered. Whole electronics unit is fixed at the main b ox with help of plug elements and lo cked

7


by screws.

1.3

Auxiliary electronics

Auxiliary electronics is mainly placed in the electronic b ox, although a few elements are placed in the main case of the device. The electronics provides following functions: · · · · · · · Device p owering by DC +5 V PMT p owering by high voltage Measurement of internal temp erature Control of illumination of FOV in viewer Polling of viewer mirror p osition Management of control light Monitoring of RS-485 line status

From the side of external control, the electronics is one multi-functional mo dule connected to RS-485 line. The mo dule executes the following functional commands: set brightness of b oth light sources (control and viewer), mo dulates the control light synchronously with micro exp osures for statistic test, which is used to test the normal op eration of the detectors and to control the parameters of the photometric channels. Position of viewer mirror is checked to prevent measurements when the mirror is o ccasionally left on axis. The high voltage converter TA-1.0N-12LS from WME company pro duces a voltage from 0 to 1000 V for PMT p owering. The converter is p owered by +12 DC and supplies 1 mA current with low ripple. The control of the output voltage is done by software as well. The presence of high voltage is indicated by a sp ecial red LED placed near other indicating LEDs. In an emergency (light overflow) the sp ecial signal from detector unit turns off the high voltage immediately. Additional functions provided by this electronics are the controls of internal temp erature of MASS and of the status of RS-485 line. Line status (data is transmitted or not) is indicated by a yellow LED. The secondary p ower unit (such as DC/DC converter TEM2-1211 from TRACO Power Company) pro duces DC +5 V for device electronics and for RS485/LPT converter (p owered thus via the line).

1.4

Star centering unit

In order to provide effective work of the optimized MASS in situations when DIMM is not used, the star centering unit is included in the design. It also helps to check whether the DIMM and piggy-back MASS devices are coaligned on the same (DIMM's) mounting. Since the new MASS device do es not have an ap erture wheel, the construction of the centering unit differs from the centering mechanism of the original MASS. The basic scanning idea is similar, but scanning of the stellar image is made with help of a triangle knife rather than by a triangle hole. This metho d has an imp ortant advantage: the star p osition can b e measured with resp ect to the real

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a)

b)

c)

50% x1 x2 x1 x2 x1 x2

Figure 1.2: Principles of the centering unit unction. a) -- scan of uniform ap erture, b) -- scan of the star image in the ap erture enter, c) --- the same for offset star. center of ap erture (see b elow), not to some initial star p osition which needs additional (manual) calibration. The Fig. 1.2 shows the light curves during scanning of uniformly illuminated ap erture, star in the ap erture center, and an offset star. Uniformly illuminated field ap erture (twilight scanning) serves for defining of the exact ap erture center. To move the triangle knife, a little stepp er motor from FDD drive with its native brass worm is used. Bip olar stepp er motor has two 18 ohm windings p owered by maximal current 200 mA. The motor has 20 step p er revolution and can by driven in quarter step mo de only, not finer. Pitch of worm equals to ab out 3 mm. So, the knife shift step as small as 0.04 mm is provided. This value (taking into account the 45 slop e of the knife edge) corresp onds to the angular step 3 , which is less than 0.01 of the field ap erture size. A separate electronic mo dule is used to control the centering unit. The stepp er motor controller shifts of triangle knife with a preset sp eed at the needed distance, checks the left and right motion limits, turns off and on motor p owering b etween centering pro cedures. Stepp er motor is p owered by DC +12 V. The mo dule is connected to RS-485 line as shown in Fig. 1.1.

1.5

Requirements to p ower supply

The p ower supply +12 DC may b e either a battery or a line regulator or a switching converter. The maximal total MASS p ower consumption is 300 mA when the high voltage is on. The main requirements for the characteristics of the p ower supply are following: · · · · Output voltage: +12 V (Min +11.5 V, Max +13 V) Max output current: greater than 0.6 A Max output voltage pulsations: less than 100 mV Op erating temp erature from -10 to +35 .

A 2-wires cable which p owers the MASS device, must have 0.5 mm 2 cross-section (AWG20) and the length not longer than 15 m. Voltage drop at the cable must b e less than 0.2 V p er one wire.

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1.6

Data exchange proto col (physical level)

Figure 1.3: Illustration of data exchange b etween host computer and mo dules. Light grey -- packet with data or command information, dark grey -- signal which confirms packet reception. Three p ossibilities are shown: 1) computer sends a command to mo dule 1, 2) computer sends a request to mo dule 2 and receives the reply, 3) an active mo dule 3 sends a data blo ck to computer. As describ ed ab ove, all information exchange b etween the host computer and MASS is executed via RS-485 line. MASS op eration needs an informational flow as large as 8 Kb/sec or 110 Kbit/sec on a serial line. So, the line with 0.5 Mbit/sec is sufficient for our purp ose. Although ATMega controller provides more faster exchange rate, the p ossibility of usage of a faultless line of 50­100 m length at lower rates is more preferable. Data transmission through RS-485 line is executed serially. Each serial byte contains 1 start bit, 8 data bits, 1 parity bit (used for sp ecial needs only), 1 stop bit. It is the standard proto col, defined at the hardware level of micro-controllers. The metho d of interaction b etween receiver and transmitter to provide faultless and effective data exchange is called an exchange proto col. The main features of the used proto col of data exchange are following: · Data and commands are transmitted in binary (non-symb olic) form · The bytes of information for transmission are merged in a packet · The inter-mo dule exchange is excluded from proto col, computer always participates in any data exchange · The packet can have a length from 1 to 31 bytes · The packet with length of 1 byte has a sp ecial function ­ signal · Each packet is started with a header byte (except signals). Header byte is marked by 1 in the parity (ninth) bit · Header contains address of the destination or departure mo dule · The last byte of the packet is 8 bits cyclic residual control · Receptor confirms the packet acceptance by sending an acknowledgment signal · A non-confirmed packet is treated as lost and is re-transmitted until reception All MASS mo dules work commonly as passive devices -- they can transmit data only in resp onse to a request from the host computer. The photometric mo dule can work as an active 10


one, i.e. it can activate the packet transmission. This ability p ermits to reach more effective data acquisition than p olling metho d. In Fig. 1.3 the three p ossible variants of data exchange are illustrated. Since the same lines of the interface is used for b oth reception and transmission, a collision of packets is p ossible. To avoid collisions, some mo dification of time windowing metho d is used. For the needed data flow and transmission rate, the used time window is ab out 500 mksec. In general, the collision problem for an exchange rate of 20% of line capacity and for three active devices (two bicounter mo dules and host computer) is severe. It was solved in case of MASS by sp ecial induce pro cedure, when the data transmission from next mo dule is started after passing data packet from the so called inductor mo dule. This way is used in MASS, to o.

1.7

RS485/LPT converter

To solve a data exchange problem with a needed rate (460 Kbit/s) we use standard LPT p ort working in EPP mo de and a sp ecial RS485/LPT converter (see [3]) with a packet pro cessing feature and a large FIFO capacity (512 bytes). Such bufferization p ermits to reduce by more than two orders the PC reaction requirements and to reduce a pro cessor load at the interrupt service by few tens times. In order to send a packet to the MASS device, the driver program writes sequentially all the packet bytes to the LPT data register except the address byte. Then, an address byte is written in the LPT address register which signals that the packet is fully loaded in the converter. Converter computes the CRC byte, adds it to the packet and transmits serially the packet via an RS-485 line. Then it waits for the mo dule resp onse and, if no fault results, asks the computer to read the replied data. When a transmission is activated by a (bi)counter mo dule, the converter receives a full packet, checks its CRC, sends back a signal ACK (or NAK in the fault case) to the mo dule and asks the computer to read received data. If computer is busy and can not read data immediately, the received data are placed into the internal FIFO buffer. The buffer can keep up to 15 full packets and provides thus the bufferization as long as 30 ms. When the computer is finally able to read data, all the data, packet by packet, are input during 1 ms. The converter uses optical coupling that insulates electrically the PC computer from the MASS instrument. The converter is connected to the LPT p ort of the PC directly and do es not require any separate p ower supply. It is p owered from the line voltage +5 DC fed by the MASS device.

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Chapter 2

Electronic modules
The electronics design is p erformed as the base of the mo dular conception explained in the Main Do cument earlier. In the next sections the circuit diagrams of the mo dules are presented. Generally accepted designations of schematic elements are used, except designation for resistors (we used a russian symb olic for them). The connectors are also marked in a sp ecial way. Connectors to external cable and wires are denoted by a letter "X", internal connectors are divided into four groups: 1) Soldered connectors are marked with a letter "S", 2) Inter-b oard connectors, which link different parts of the same mo dule -- with "I", 3) Connectors to internal bus, which links the different mo dules -- "Y", 4) Sp ecial connectors for In System Programming technique are denoted as "ISP". The nominal values of passive elements are shown on the schemes. The active element features are shown in sp ecification tables which are included, to o. Comp onent manufacturer are not shown in cases of widespread parts. Connectors, which are parts of PCB, don't include in the tables. Also, this chapter contains the schematic views of the mo dule PCBs with the comp onent placement for easy identification of the schematic element with the real comp onent used.

2.1

Detectors unit

As describ ed ab ove, detectors (photometric) unit consists from two identical bicounter mo dules, placed in parallel at the same PCBs. In the Fig. 2.1 a circuit diagram for whole unit is presented. Bicounter mo dules are shown schematically by blo cks. Comp onents which do not b elong to bicounter mo dules are shown explicitly. Further, these comp onents are marked by prefix * at the PCB01C.

2.2

Bicounter mo dule

The circuit diagrams of the analog and digital parts of the bicounter are shown in Fig. 2.2 and Fig. 2.3. PCB views are presented in Fig. 2.4, Fig. 2.5 and Fig. 2.6.

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Table 2.1: Sp ecification for detectors unit electronics. Item 1 2 3 4 5 6 7 8 9 Part D1 Z1 C1 C2, C3 R1 Y1 PCB01A PCB01B PCB01C Name IC NC7SZ32M5 Quartz 14.746 MHz SMD capacitor 2KV SMD capacitors SMD resistor Line conn. Printed b oard Printed b oard Printed b oard Manufacturer Fairchild -- -- -- -- -- Custom Custom Custom Q-ty 1 1 1 1 2 1 1 1 1 Rem SOT-23, Gate OR HC49S 1208 size 0805 size 0805 size Soldered Fig. 2.4 Fig. 2.5 Fig. 2.6

Table 2.2: Sp ecification for an analog part of the Bicounter mo dule. Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Part D1, D2 D3 D4, D5 D6, D7 R1-R4 R5-R22 C1, C2 C3, C4 C5-C8 C9-C19 C20-C22 L1-L4 R23-R33 PMT1,2 I1-I3 I4 Name IC SA5205AD IC AD1580ART IC AD8400AR1 IC AD8611AR SMD resistors SMD resistors SMD capacitors SMD capacitors SMD capacitors SMD capacitors SMD Tantal capac. SMD inductances SMD resistors E678-12 Pins connector Pins connector Manufacturer Philips Analog Dev. Analog Dev. Analog Dev. -- -- -- -- -- -- -- Bourns -- Hamamatsu -- -- Q-ty 2 1 2 2 4 18 2 2 4 10 3 4 11 2 3 1 Rem

0805 size 1208 size 0805 size 1208 size, 250V 0603 size 0805 size A size 1812 size 0805 size PMT so ckets PBS2-2, soldered PLD2-12

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Dividers A & B

Bicounter 1

I_A ANOD_A GND

Amplifiers A & B
I_B

ANOD_B GND

INP_A VCC CS_B CS_A MOSI SCK INP_B I_B I_A GND

Counters A & B

XTAL1

XTAL2

SCK

SS

MISO

MOSI

Y1
1

*Z1
C2 12p R1 120 C3 12p

HV GND

1 2

C1 1n

S1

2 1

D1
4

2 3 4 5

XTAL1

MISO

SCK

Dividers A & B

Bicounter 2

I_A ANOD_A GND

Amplifiers A & B
I_B ANOD_B GND

INP_A VCC CS_B CS_A MOSI SCK INP_B I_B I_A GND

Counters A & B

Figure 2.1: Circuit diagram of the Detectors unit electronics. See circuit diagram for a bicounter in the further figures.

SS

MOSI

6

VCC GND LINE A OVLIGHT LINE B STROB

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HV

R5 510K
C9 100n

L1 10mH
C18 100n C20 1.5mF

L3 10mH

1

R6 510K R7 510K

6

R13 270K R1 100K
R3 10K C1 68

R23 7.5K

K DY1 DY2 DY3 DY4 DY5 DY6 DY7 DY8 A

12 11 10 2 9 3 8 4 7 5

R27 * R8 510K R9 510K I1/1 R10 510K R11 510K I1/2 ANOD_A
C5 15p

C7 5.6n
2

D1
5

C16 5.6n
2 3

D6
8 7

R32 10

C11 5.6n
R24 91 R28 91

C12 10n GND R12 510K

R31 1.2K

C22 2.2mF

PMT1

I4
D4
8 A W B SDI CS' CLK 4 3 5 7 1 4 9 5 7 3

C3 100n ANOD_A GND I_A R14 510K

I1/1 I1/2 I3/1 C15 100n

1

D3 D5
8A 7W 1 B SDI 4 3 CS' 5 CLK

11 8 10 2 6 12

PMT2
1

R15 510K R16 510K

K DY1 DY2 DY3 DY4 DY5 DY6 DY7 DY8 A

12 11 10 2

OUT_B MOSI CS_B SCK CS_A VCC OUT_A I_A I_B GND GND GND

C10 100n

3 8 4 7 5 6

R19 510K R20 510K

R25 7.5K

9

R30 *

C19 100n

R18 510K

R21 510K R22 270K I2/1 ANOD_B
C6 15p

C8 5.6n
2

D2
5

C17 5.6n
2 3

D7
8 7

C21 1.5mF

R4 10K

C2 68

C14 10n ANOD_B GND I_B I2/1 I2/2 I3/1 I3/2 I3/2 I_B I_A I2/2 GND

Figure 2.2: Circuit diagram of the analog part of the Bicounter mo dule electronics. PMT divider, pulse amplifier and discriminator with level control.

R29 91

R26 91

15
R17 510K R2 100K C4 100n

L2 10mH

L4 10mH

R33 10

C13 5.6n


C1 100n

VCC
R3 5.6K R4 5.6K C3 10mF C2 100n

I4
INP B VCC CS_A CS_B MOSI SCK INP A I_A I_B GND GND GND
1 3 7 9 4 5 11 8 10 2 6 12 15 9 10 C1 C0 7 1 2 C0 C1

D2:A
Q0 Q1 Q2 MR Q3 3 4 5 6 23 24 25 26 27 PC0 PC1

D3

GND
AVCC 18 20 19 22

PC2 PC3 PC4 PC5 RESET PB0 PB1 PB2/SS OC2/MOSI PB4/MISO PB5/SCK XTAL1 XTAL2

ATMEGA8-AI16

AREF ADC6 ADC7

D2:B
Q0 Q1 Q2 MR Q3 11 12 13 14

28 29 12 13 14 15 16 17 7

PD0/RXD PD1/TXD PD2/INT0 INT1/PD3

30 31 32 1

STROB

T0/PD4 2 PD5/T1 PD6/AIN0 PD7/AIN1 9 10 11

R5 10K

16

R1 2.2M R2 2.2M

8

VCC

OVLIGHT
D4
1

D1:A
3 1 2

ISP/1 ISP/2 ISP/3 RESET MOSI SCK MISO GND

XTAL0 XTAL1 MOSI SCK MISO SS

RO RE DE DI

6

LINE B LINE A

2 3 4

7

D1:B
5 7 6

ISP/4 ISP/5 ISP/6

Figure 2.3: Circuit diagram of the digital part of the Bicounter mo dule electronics. Counters and microcontroller unit.


Table 2.3: Sp ecification for a digital part of the Bicounter mo dule. Item 1 2 3 4 5 6 7 8 Part D1 D2 D3 D4 R1-R5 C1, C2 C3 I4 Name IC 74HC4520D IC LM2903M IC ATMega8-16AI IC ADM1485AR SMD resistors SMD capacitors SMD Tantal capac. Pins connector Manufacturer Philips Nat.Semicond. Atmel Analog Dev. -- -- -- -- Q-ty 1 1 1 1 5 2 1 1 Rem

0805 size 0805 size B size PBD2-12

PMT side

PMT2 (B)

PMT1 (A)

R7 R9 R11

R16 R18 R20

C2 C3

C4

Figure 2.4: Placement of the comp onents on printed circuit b oard of the PMT voltage divider. Designations are the same as in circuit diagrams in Fig. 2.2.

C1

R13

R22

R2

R1
R8 R5

R3

R4

Bicounter 2

Bicounter 1

Opposite side

I2

R12 R10

I1
*C1

R21 R19 R17 R14 R15

I3

R6

*S1

17


Bicounter 2
I1
C5 C7

Bicounter 1
I2
C6 C8

C10

C9

I3

D1
L1

D2
L2

D5

Figure 2.5: Placement of the comp onents on printed circuit b oard of the Pulse amplifier and discriminator with level control. Designations are the same as in circuit diagrams in Fig. 2.2.

C16 C11 C12
R24 R28 R23

R31 +

R26 R29 R25

C17 C13 C14
+

C15

C19

C20 C18

C21

D6
R27 R32

D4

D7
R30 R33

D3

+

L4

Bicounter 2
I4
1

L3

C22

1

I4

Bicounter 1

*C2

+

Figure 2.6: Placement of the comp onents on printed circuit b oard of the digital part of the Bicounter. Designation are the same as in circuit diagrams in Fig. 2.3.

R2

R1
C1

R5

R4

R3

C3

*Y1

D1

*Z1

1

D2
D4
*D1

*C3

C2

D3

ISP
1

*R1

18


2.3

Auxiliary mo dule

The circuit diagrams of this mo dule are shown in Fig. 2.7 and Fig. 2.9. PCB views are presented in Fig. 2.8 and Fig. 2.10. On the PCB2A main part of the auxiliary mo dule is placed. So as this PCB is installed in removable electronics b ox, it is connected with other parts of auxiliary electronics, placed in the main case of the device, with help of connector I5. The connector is mounted on cross-plate PCB02B. Further connections made soldered. Table 2.4: Sp ecification for the Auxiliary electronics. Item 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 Part D1 D2 D3 D4 D5 D6 D7 D8 D9 Z1 R1-R22 C1 C2, C4 C5 C3-C11 V1-V3 V4 V5, V6 ISP X1 X2 Y2 I5(A) I5(B) PCB02A PCB02B PCB02C PCB02D Name Mo d. TEM2-1211 IC LM2904M Mo d. TA-1.0N-12LS IC TMP36 IC LM7101BM5 IC ATMega8-16AI IC AD8402AR10 IC ADM1485AR IC SS441 Quartz 14.746 MHz SMD resistors Alum.capacitor SMD tantal capac. SMD tantal capac. SMD capacitors L513(SV,SG,SY) KPL3015G KPL3015R ISP connector Power conn. DJK-02B Line conn. DB9F Pins conn. (pins) Pin