CAEN V792 ADC

Property

Sensitivity: 100 fC/channel

Manual

Media:CAEN_V792_Manual.pdf

Module address

Rotary dials

The rotary dials for the address were set by the factory to be 32 bit addressing with "e" and "e" on the last dials.

We would like to use 24 bit addressing so lets set the first two dials to "ee". The last two dials should also be set to something non-zero in order to permit 32 bit addressing. The MVME-6100 board only has a small amount of 32 bit VME addressing space mapped to the MVME's address space.

               VME                             CPU
    A24   0x000000-0xffffff           0x90000000-0x90ffffff
    A32   0x08000000-0x11ffffff       0x80000000-0x89ffffff

If you set the last two dials to 0 8 then the addressing will look like

    c792Init 0xee0000     (for A24 addressing)

or

    c792Init 0x08ee0000   (for A32 addressing)

Data banks

The ADC module library will send the entire block over unless you set the ADC for specification.

Below is shown the data structure for Multi-Event Buffer. The data is organized in events[1]. The header, which contains the crate number and the number of converted channels(the second row in the table), the data words - the number of the channel, the Under-Threshold (UN) bit, the Overflow (OV) bit and the 12-bit converted value(ADC COUNTS) and event counter is in The End of Block.

The Header

The bits[26..24] - shows the word type(010 - header);
The bits[23..16] - the crate number;
The bits[13...8] - the memorized channel number.

The data words

The bits[26..24] - the type of word (000 - datum);
The bits[21..16] - the data output channel number;
The bit[13] - the underthreshold;
The bit[12] - the overflow;
The bits[11...0] - the 12 bit converted data.

The End of Block(EOB)

The bits[26..24] - identification of the word type(100 - EOB);
The bits[23..0] - the event counter value.

26	25	24	23	22	21	20	19	18	17	16	15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	1	0	CRATE NUMBER								0	0	MEM. CHANNELS(2)
0	0	0			CHANNEL(2)								UN	OV	ADC COUNTS
0	0	0			CHANNEL(5)								UN	OV	ADC COUNTS
1	0	0	EVENT COUNTER(m)
0	1	0	CRATE NUMBER								0	0	MEM. CHANNELS(3)
0	0	0			CHANNEL(0)								UN	OV	ADC COUNTS
0	0	0			CHANNEL(17)								UN	OV	ADC COUNTS
0	0	0			CHANNEL(3)								UN	OV	ADC COUNTS
1	0	0	EVENT COUNTER(m+3)

Assuming we read all 32 channels then the data block will look like

ADC1:
Crate #=0
Ch       data    Hex
0       3896    f8005f38
16      3896    f8105f38
1       3896    f8015f38
17      3896    f8115f38
2       3896    f8025f38
18      3896    f8125f38
3       3896    f8035f38
19      3896    f8135f38
4       3896    f8045f38
20      3896    f8145f38
5       3896    f8055f38
21      3896    f8155f38
6       3896    f8065f38
22      3896    f8165f38
7       3896    f8075f38
23      3896    f8175f38
8       3896    f8085f38
24      3896    f8185f38
9       3896    f8095f38
25      3896    f8195f38
10      3896    f80a5f38
26      3896    f81a5f38
11      3896    f80b5f38
27      3896    f81b5f38
12      3896    f80c5f38
28      3896    f81c5f38
13      3896    f80d5f38
29      3896    f81d5f38
14      3896    f80e5f38
30      3896    f81e5f38
15      3896    f80f5f38
31      3896    f81f5f38
Event Counter=46=0xfc00002e

ROC library

caen775Lib.c_Code

The command below will compile the above library.

v792 >ccppc -fno-builtin -fno-for-scope -fstrength-reduce -mlongcall -mcpu=604 -DCPU=PPC604 -DVXWORKS -D_GNU_TOOL 
-DVXWORKSPPC  -I/usr/local/coda/2.5/common/include -I../h   -c -o v792Lib.o caen792Lib.c

ECL input polarity

Control lines

Go back VME_modules Go back