C.A.E.N. Technical Information Manual

MOD. C193

32 CHANNEL PROGRAMMABLE DISCRIMINATOR

Table of contents

1. DESCRIPTION

1.1 FUNCTIONAL DESCRIPTION

2. SPECIFICATIONS

2.1 PACKAGING
2.2 EXTERNAL COMPONENTS
2.3 CHARACTERISTICS OF THE SIGNAL
2.4 POWER REQUIREMENTS

3. CAMAC FUNCTIONS

4. OPERATING MODES

4.1 LOCAL MODE
4.2 REMOTE MODE
4.3 OUTPUT PULSES WIDTH ADJUSTMENT

5. CALIBRATION PROCEDURE

5.1 NECESSARY INSTRUMENTS
5.2 PRELIMINARY OPERATIONS

6. TEST PROCEDURE

FUNCTIONAL BLOCK DIAGRAM OF THE MODULE

1. DESCRIPTION

1.1 FUNCTIONAL DESCRIPTION

The model C193 is a 32 channel PROGRAMMABLE DISCRIMINATOR housed in a 2-unit wide CAMAC unit.

Each channel is NON UPDATING type, and consists of a DAC connected with a hybrid discriminator.

The module can be programmed either in local mode (via front panel controls) or in remote mode (via CAMAC). An internal 80C32 microprocessor controls both operating modes.

The module accepts 32 negative differential inputs via the front panel flat cable connector "IN". The corresponding outputs are differential ECL and they are presented at the front panel flat cable connector "OUT". The output pulses width is adjustable via the front panel trimmer "WDT" and it does not depend on the over threshold time. A front panel connector (AN-OUT) allows the output pulses width to be monitored.

For each channel, numbered from 0 to 31, the threshold value can be set in a range from 10 mV to 400 mV (guaranteed) and over (up to 510 mV), in 2 mV steps. The selected threshold values are stored into an internal EEPROM. It is also possible to set the same threshold value for all channels and to increase/decrease it. For this purpose, the module is provided with three dummy channels numbered 92, 93, 94.

The calibration operations are accomplished via CAMAC by using the CAMAC functions in non-standard mode (see par. 5).

The functional block diagram of the module is shown in Figure 1.1.

Figure 1.1 Functional Block Diagram of the Module.

2. SPECIFICATIONS

2.1 PACKAGING

2-unit wide CAMAC module.

2.2 EXTERNAL COMPONENTS

• No.1 3-digit segment LED display "THR MON", showing the threshold value referred to the selected channel.
• No.1 momentary lever switch "UP-DOWN" (horizontal writing). This switch allows the threshold of the selected channel to be increased/decreased in 2 mV steps.
• No.1 pushbutton "WR". By pressing this pushbutton the selected threshold value is stored into the module's internal EEPROM.
• No.1 2-position lever switch "REM". By setting this switch to the "REM" position, the module operates in REMOTE mode (to the opposite position, the LOCAL operating mode is allowed).
• No.1 momentary lever switch "UP-DOWN" (vertical writing), for the channel number selection.
• No.1 2-digit segment LED display "CH", showing the selected channel number (0 to 31) or 92, 93, 94 (see par. 4., OPERATING MODES).
• No.1 trimmer "WDT", for the output pulse width setting.
• No.1 LEMO 00 type connector "AN-OUT", where a voltage level (~ -6 V to -0.5 V) function of the output pulse width is available.
• No.1 64-pin fIat cable connector "IN". Channel inputs.
• No.1 64-pin flat cable connector "OUT". Channel outputs.

2.3 CHARACTERISTICS OF THE SIGNALS

INPUTS:

• negative polarity;
• minimum pulse width: 4 nsec;
• double pulse resolution: 8 nsec;
• maximum level: ±5 V;
• maximum frequency: 100 MHz;
• minimum over threshold time: 3 nsec;
• termination: 50 Ohm (on request, it is possible to change the termination value);

OUTPUTS:

• differential ECL;
• pulse width: adjustable in a range from 8 nsec to 35 nsec;
• termination: 100 Ohm.

INPUT/OUTPUT DELAY:

• 10.5 nsec ±1.5 nsec

2.4 POWER REQUIREMENTS

-6 V at 4.8 A (*)

+6 V at 1.3 A (*)

3. CAMAC FUNCTIONS

4. OPERATING MODES

The model C193 can be programmed either in local (via front panel controls) or in REMOTE mode (via CAMAC).

For both modes, the following paragraphs describe the operations listed below:

• how to set the threshold value correlated with an individual channel;
• how to set a common threshold value for all channels.

4.1 LOCAL MODE

4.1.1 THRESHOLD VALUE SETT1NG (FOR INDIVIDUAL CHANNELS)

1. Insert the module into a CAMAC slot.
2. Configure the system as required.
3. On the module's front panel, set the two-position lever switch "REM" to the unlabelled position: the LOCAL operating mode is enabled.
4. Turn ON the CAMAC crate. After a few seconds the "CH" display shows "0" (number of the current channel) and the "THR MON" display shows the corresponding threshold value (mV) previously stored into the internal EEPROM.
5. Let the module warm-up tor at least half an hour.
6. By the momentary lever switch "UP-DOWN" located on the left side of the module (vertical writing), select the number of the channel for which the new threshold value has to be defined (on the "CH" display the selected channel number is shown).
7. By the momentary lever switch "UP-DOWN" located on the module's upper side (horizontal writing), select the required threshold value. The threshold value is shown on the "THR MON" display and the corresponding writing is blinking.
8. Press the "WR" pushbutton: after a few seconds, the selected threshold value is stored into the module's internal EEPROM and the corresponding writing on the "THR MON" display comes steady.
9. Repeat the procedural steps 6 to 8 for each of the remaining channels.

4.1.2 COMMON THRESHOLD VALUE SETTING

1. If it is necessary, carry out the steps 1 to 5 listed in the preceding paragraph 4.1.1.
2. By the momentary lever switch "UP-DOWN" located on the left side of the module (vertical writing), increase the number shown on the "CH" display until it is equal to "92" (*) ("92" is displayed after "31").
3. By the momentary lever switch "THR" located on the module's upper side, select the required threshold value. This value (mV) is shown on the "THR MON" display and the corresponding writing is blinking.
4. Press the "WR" pushbutton: after a few seconds, the selected threshold value is stored into the module's internal EEPROM and is assumed for all channels. The corresponding writing on the "THR MON" display becomes steady and the number "92" is shown on the "CH" display.

4.2 REMOTE MODE

4.2.1 THRESHOLD VALUE SETTING (FOR INDIVIDUAL CHANNELS)

1. Insert the module into a CAMAC slot.
2. Configure the System as required.
3. On the module's front panel, set the two position lever switch "REM" to the "REM" position: the REMOTE operating mode is enabled.
4. Turn ON the CAMAC crate: after a few seconds, the "CH" display shows "0" (number of the current channel) and the "THR MON" display shows the corresponding threshold value (mV) previously stored into the internal EEPROM of the module.
5. Let the module warm-up for at least half an hour.
6. According to the selected channel number (0-15, 16-31) perform an F(16) N A(0-15) or an F(16) N+1 A(n) (where n=channel number - 16) CAMAC function with the WRITE Lines W1+W8 set to the required threshold value (resolution = 2 mV per bit): after a few seconds the new threshold value is stored into the internal EEPROM and the two displays "CH" and "THR MON" show the number of the selected channel and the new threshold value (mV) respectively.

4.2.2 COMMON THRESHOLD VALUE SETTING

1. If it is necessary, carry out the steps 1 to 5 listed in the preceding paragraph 4.2.1.
2. Perform an F(17) N A(1) or an F(17) N+1 A(1) CAMAC function with the WRITE Lines W1+W8 set to the required threshold value (resolution = 2 mV per bit): after a few seconds, the new threshold value is stored into the module's internal EEPROM, and the two displays "CH" and "THR MON" show, respectively, "0" and the set threshold value (mV).

4.2.2.1 COMMON THRESHOLD VALUE DECREASE

1. If it is necessary, carry out the steps 1 to 5 listed in the preceding paragraph 4.2.1.
2. Perform an F(17) N A(2) or an F(17) N+1 A(2) CAMAC function with the WRITE Lines W1+W8 set to the required decrease value (resolution =2 mV per bit): after a few seconds the updated threshold values are stored into the module's internal EEPROM and the two front panel displays show the "0" channel number and the corresponding threshold value.

4.2.2.2 COMMON THRESHOLD VALUE INCREASE

1. If it is necessary, carry out the steps 1 to 5 listed in the preceding paragraph 4.2.1.
2. Perform an F(17) N A(3) or an F(17) N+1 A(3) CAMAC function with the WRITE Lines W1+W8 set to the required increase value (resolution =2 mV per bit): after a few seconds the updated threshold values are stored into the module's internal EEPROM and the two front panel displays show the "0" channel number and the corresponding threshold value.

4.2.3 THRESHOLD VALUE READING

To readout any channel threshold value, carry out the following operation:

According to the number of the selected channel perform an F(0) N A(n) or an F(0) N+1 A(n) where

• "N" selects the channels group 0 to 15 with n=0+15;
• "N+l" selects the channels group 16 to 31 with n=channel number - 16;

The threshold value is shown on the R1+R8 READ Lines.

X = TRUE and Q = TRUE

4.2.4 LOCAL MODE ENABLING

To enable the LOCAL operating mode via CAMAC without switching off the CAMAC crate, carry out the following operations:

1. On the module's front panel, set the "REM" lever switch to the unlabelled position.
2. If the local operating mode had been disabled via CAMAC, perform an F(26) N or an F(26) N+1 CAMAC function several times until X and Q responses are TRUE.

4.2.5 LOCAL MODE DISABLING

To disable the LOCAL operating mode, carry out the following operations:

1. On the module's front panel, set the "REM" lever switch to the "REM" position.
2. Perform an F(24) N or an F(24) N+1 CAMAC function several times until X and Q responses are TRUE.

4.3 OUTPUT PULSES WIDTH ADJUSTMENT

To change the width of the output pulses, carry out the adjustment operations listed below.

4.3.1 NECESSARY INSTRUMENTS

• No.1 Pulse Generator.
• No.1 Oscilloscope (minimum band width: 100 MHz).
• No.1 NIM-ECL-NIM TRANSLATOR, model CAEN N92.

4.3.2 ADJUSTMENT OPERATIONS

1. Connect one of the C193 output channels with one of the eight ECL input channels of the N92 module.
2. Connect the N92 output channel corresponding to the selected input, with the oscilloscope input (terminated in 50 Ohm impedance).
3. Via Pulse Generator, send an overthreshold input signal to the C193 input channel corresponding to the selected output.
4. By a screwdriver, turn the "WDT" trimmer (located on the C193 front panel) until the required output pulse width is reached (8 nsec to 35 nsec).

5. CALIBRATION PROCEDURE

Each of the Cl93 channels consists of an 8-bit DAC connected with a hybrid discriminator circuit.

Since the hybrid circuits differ from one another in the offset and amplification parameters, it is necessary to calibrate the module before using it for the first time. For this reason the module is carefully calibrated before delivering it to customers.

The calibration operations are enabled (through the module's internal microprocessor) by inserting the internal jumper "TEST": in this way, the CAMAC functions act as follows:

Whenever a threshold value setting operation is accomplished, the internal software program of the module writes the following value into the DAC corresponding to the selected channel:

N_DAC = (N_THR - C_O) / C_A

where: N_THR = CAMAC THRESHOLD, C_O = OFFSET PARAMETER, C_A = AMPLIFICATION PARAMETER.

At the same time, on the "THR" front panel display the following value is shown:

N_DISPLAY = N_THR *2 (-mV)

The calibration operations consist of setting the C_O and C_A values for each channel.

5.1 NECESSARY INSTRUMENTS

• No.1 Oscilloscope (minimum band width: 100 MHz).
• No.1 Pulse Generator capable of producing output pulses having the following characteristics:
  1. pulse amplitude: -20 mV to -350 mV;
  2. pulse duration: 10 nsec;
  3. frequency: 1 MHz.
• No.1 CAMAC crate provided with a CAMAC controller.
• No.1 NIM-ECL-NIM translator, model CAEN N92.
• No.1 Attenuator module, model CAEN N109 or model CAEN N147A with a C117B CAMAC interface.

5.2 PRELIMINARY OPERATIONS

1. Connect Pulse Generator, Attenuator and Oscilloscope as shown in the figure below:

   

2. Generate a pulse having the following characteristics:
   1. width: ~ 10 nsec;
   2. amplitude: ~ -350 mV;
   3. rise time/fall time: 2 nsec;
   4. frequency: 1 MHz.
   Assume the pulse amplitude as V_H.
3. Generate a pulse having the following characteristics:
   1. width, rise time/fall time, frequency: same as at step 2;
   2. amplitude: -30 mV.
   Assume the pulse amplitude es V_L.
4. On the module's printed circuit board, insert the jumper labelled "TEST": the module is now enabled to operate in CALIBRATION MODE.
5. Connect instruments and modules as shown in the figure below:

   

   The Attenuator's output has to be connected with the first C193 input channel to be calibrated.

6. Turn ON instruments and CAMAC crate.
7. Via Pulse Generator, generate the V_H pulse.
8. Via CAMAC Controller, perform several F(l6) N A(0-15) or F(16) N+l A(CHN°-16) (according to the selected C193 channel) with the W1+W8 WRITE Lines set to decreasing values beginning from 255. When the W1+W8 value is equal to the discrimination threshold corresponding to the V_H input pulse (an output signal is shown on the oscilloscope), assume this value as N_dacH.
9. Via Pulse Generator, generate the V_L pulse.
10. Via CAMAC Controller, perform several F(16) N A(0-l5) or F(l6) N+l A(CHN°-16) (according to the selected C193 channel) with the W1+W8 WRITE Lines set to increasing values beginning from 0. When the W1+W8 value is equal to the discrimination threshold corresponding to the V_L input pulse (an output signal is shown on the oscilloscope), assume this value as N_dacL.
11. Perform an F(24) N and, after a few seconds, an F(16) N A(0-l5) or F(16) N+1 A(CHN°-16) (according to the selected C193 channel) with the W1+W8 WRITE Lines set to round (50*C_A) where:

    C_A = (V_HV_L) / (N_dacH-N_dacL round=the nearest integer value of...

    After a few seconds, the channel number and the W1+W8 values are shown on the relevant front panel displays.

    THE AMPLIFICATION PARAMETER CORRELATED WITH THE SELECTED CHANNEL IS NOW STORED INTO THE INTERNAL EEPROM OF THE MODULE.

12. Perform an F(26) N and, after a few seconds, an F(16) N A(0-15) or F(16) N+1 A(CHN°-16) (according to the selected C193 channel) with the W1+W8 WRITE Lines set to:

    round [(V_H/2) - (N_dacH * C_A/100)].

    If the formula above gives a negative result, it is necessary to use the following one: (-1) * { round [(VH/2) - (NdacH * CA/100)]} + 128

After a few seconds, the channel number and the W1+W8 value are shown on the relevant panel displays.
THE OFFSET PARAMETER CORRELATED WITH THE SELECTED CHANNEL IS NOW STORED INTO THE INTERNAL EEPROM OF THE MODULE.

13. Repeat the procedural steps 7 to 12 for each of the remaining channels.
14. Turn 0FF instruments and crate.
15. Remove the "TEST" jumper from the module's printed circuit board.

THE MODULE IS NOW READY TO OPERATE.

6. TEST PROCEDURE

6.1 INTRODUCTION

The operations to be performed to test the module are listed in the procedure below and have to be carried out according to their numerical sequence.

None of the procedural steps can be omitted.

Each procedural step contains the operation to be performed and the corresponding effect of verification to be accomplished.

6.2 NECESSARY INSTRUMENTS

• No.1 Oscilloscope (minimum band width: 100 MHz).
• No.1 Pulse Generator capable of producing pulses with the following characteristics:
  1. pulse amplitude: -10 mV to -500 mV;
  2. pulse duration: 10 nsec;
  3. maximum frequency: > 100 MHz.
• No.1 CAMAC crate provided with a CAMAC controller.
• No.1 NIM-ECL-NIM translator, model CAEN N92.
• No.1 Attenuator module, model CAEN N109 or model CAEN N147A with a C117B CAMAC interface.

6.3 PROCEDURE

CAUTION: turn 0FF the CAMAC crate before inserting or removing the module.

1. Connect instruments and modules as shown in the flgure below:

   

   The Attenuator's output has to be connected with the first C193 input channel to be tested (CH 0).

2. On the module's front panel, set the two-position lever switch "REM" to the unlabelled position: the LOCAL operating mode is enabled.
3. Turn ON instruments and CAMAC crate: after a few seconds, on the module's front panel, the "THR MON" display lights UP and shows a threshold vaiue (the last value stored into the internal EEPROM), then the "CH" display shows the current channel number (0).
4. By the momentary lever switch "THR" select a new threshold value (in 2 mV steps): the "THR MON" display is blinking.
5. Press the "WR" pushbutton: the new threshold value is stored into the internal EEPROM and the "THR MON" display writing becomes steady.
6. By the momentary lever switch "UP-DOWN" (vertical writing) select another channel.
7. Repeat the procedural steps 4 to 6 for each of the remaining channels (up to CH31).
8. By the momentary lever switch "UP-DOWN" (vertical writing) select the dummy channel 92.
9. By the momentary lever switch "THR" select a new common threshold value: the "THR MON" display is blinking.
10. Push the "WR" pushbutton: after a few seconds the "THR MON" display writing becomes steady.
11. By the momentary lever switch "UP-DOWN" (vertical writing) select a channel number 0 to 31 and verify that the selected new threshold value is shown on the "THR MON" display. Repeat this operation for each of the remaining channels.
12. By the momentary lever switch "UP-DOWN" (vertical writing) select the dummy channel 93.
13. By the momentary lever switch "THR" select a threshold decrease value: the "THR MON" display is blinking.
14. Press the "WR" pushbutton: after a few seconds the new common threshold value is stored into the internal EEPROM and the "THR MON" display becomes steady.
15. By the momentary lever switch "UP-DOWN" (vertical writing) verify that the new threshold value is the same for all channels (0 to 31).
16. By the momentary lever switch "UP-DOWN" (vertical writing) select the dummy channel 94.
17. By the momentary lever switch "THR" select a threshold increase value: the "THR MON" display is blinking.
18. Press the "WR" pushbutton: after a few seconds, the new common threshold value is stored into the internal EEPROM and the "THR MON" display becomes steady.
19. By the momentary lever switch "UP-DOWN" (vertical writing) verify that the new threshold value is the same for all channels.
20. By the momentary lever switch "UP-DOWN" (vertical writing) select one of the 32 discriminator channels (0 to 31).
21. Via Pulse Generator, send an overthreshold input signal to the selected C193 channel.
22. With a screwdriver, turn the "WDT" trimmer (located on the C193 front panel) and verify that the output pulse displayed on the Oscilloscope can vary in a range from 8 nsec to 35 nsec.
23. Via Pulse Generator, inhibit the input signal.
24. On the module's front panel, set the two-position lever switch "REM" to the "REM" position: the REMOTE operating mode is enabled.
25. According to the selected channel number, perform an F(16) N A(0-15) or an F(16) N+1 A(n) (where n=channel number - 16) CAMAC function, with the W1+W8 WRITE Lines set to a new threshold value (LSB=2 mV): after a few seconds the selected threshold value is stored into the internal EEPROM and it is displayed on the "THR MON" display.

    Any attempt to perform another CAMAC operation before the updated threshold value is shown, will generate X = TRUE and Q = FALSE

26. According to the selected channel number, perform an F(0) N A(0-15) or an F(0) N+1 A(n) (where n=channel number - 16) CAMAC function: the set threshold value is read by the R1+R8 READ Lines.
27. Via Pulse Generator, send an overthreshold input signal through the selected C193 channel: on the Oscilloscope, an output pulse is displayed.
28. Repeat the procedural steps 25 to 27 for each of the remaining channels.
29. Perform an F(17) N A(1) or an F(17) N+1 A(1) CAMAC function with the WRITE Lines W1+W8 set to the required threshold value (LSB = 2 mV): after a few seconds, the new common threshold value is stored into the module's internal EEPROM, and the two displays "CH" and "THR MON" show "0" and the set threshold value (mV) respectively.

    Any attempt to perform another CAMAC operation before the new threshold value is shown, will generate X = TRUE and Q = FALSE

30. According to the selected channel number, perform an F(0) N A(0-15) or an F(0) N+1 A(n) (where n=channel number - 16) CAMAC function: the set threshold value is read by the R1+R8 READ Lines.
31. Repeat the procedural step 30 for each of the remaining channels: the read threshold value must be the same for all channels.
32. Perform an F(17) N A(3) or an F(17) N+1 A(3) CAMAC function with the WRITE Lines W1+W8 set to an increment value of the common threshold (LSB = 2&nmbsp;mV): after a few seconds, the updated threshold values are stored into the module's internal EEPROM and the two front panel displays show the "0" channel number and the corresponding threshold value.

    Any attempt to perform another CAMAC operation before the updated threshold value is shown, will generate X = TRUE and Q = FALSE

33. According to the selected channel number, perform an F(0) N A(0-15) or an F(0) N+1 A(n) (where n=channel number - 16) CAMAC function: the set threshold value is read by the R1+R8 READ Lines.
34. Repeat the procedural step 33 for each of the remaining channels: the read threshold value must be the same for all channels.
35. Perform an F(17) N A(2) or an F(17) N+1 A(2) CAMAC function with the WRITE Lines W1+W8 set to a decrease vaiue of the common threshold (LSB = 2 mV): after a few seconds, the updated threshold values are stored into the module's internal EEPROM and the two front panel displays show the "0" channel number and the corresponding threshold value.

    Any attempt to perform another CAMAC operation before the updated threshold value is shown, will generate X = TRUE and Q = FALSE

36. According to the selected channel number, perform an F(0) N A(0-15) or an F(0) N+1 A(n) (where n=channel number - 16) CAMAC function: the set threshold value is read by the R1+R8 READ Lines.
37. Repeat the procedural step 36 for each of the remaining channels: the read threshold value must be the same for all channels.
38. Via Pulse Generator, send an overthreshold input signal through the selected C193 channel: on the Oscilloscope, an output pulse is displayed.
39. Repeat the preceding procedural step for each of the remaining channels.

THE MODULE IS NOW TESTED AND OPERATES CORRECTLY.