LeCroy 2232A 32-Input Differential ADC

* High sensitivity: 12 bits or 0.025% resolution
* Two digitizing modes: Continuous Scan or Single Shot
* Asynchronous readout: any channel can be read at any time
* Independent measurement: operation same as 32 separate ADC's
* Bipolar or monopolar operation over a 10 volt range
* Differential Inputs: Common mode range of +/-5 volts
* Flexible readout: Block transfer (DMA) or address selection

The LeCroy Model 2232A is a 32-input, 12-bit ADC intended for use in general-purpose voltage-monitoring applications. The >10 Mhom inputs of the 2232A respond to voltages over a 10-volt range, converting them to proportional 12-bit digital data words. An on-board switch provides the choice of a monopolar mode, 0 to +10 volts, or a bipolar mode, -- 5 to +5 volts. The differential inputs suppress the contribution from common mode signals and high frequency noise is filtered out.

The voltage levels at the 32 inputs on the front panel connectors are converted sequentially, requiring 550 usec per channel for conversion and storage in the RAM (Random Access Memory). During readout the addressed 12-bit data word is placed on the Dataway without any interference of a store cycle, should one be present (asynchronous readout). In the Contin- uous Scan Mode each channel of the 2232A continuously updates its memory every 18 msec. Random access readout onto the CAMAC Dataway proceeds via the flexibility of reading individual channels or subgroups of the 32 channels more frequently than others, permitting low maintenance items to be monitored compatibly with ones that demand a higher level of attention.

In the Single Shot Mode the CAMAC function F(25)- N initializes the Analog Switch Address to Channel 1 and starts a single scan of all 32 channels. This may also be accomplished by applying a TTL pulse to a front-panel Lemo-type connector (Scan Trigger). This mode thus permits all 32 measurements to be more clearly related in time to some external event or reference. LAM is generated after scan is completed and Q=O is generated after channel 32 is readout.

The 2232A finds useful application in the monitoring of power supply voltages, magnet currents, temperature or pressure transducers, and in a variety of other situations where computer-compatible high resolution measuring of dc voltages is desired.

Specifications

Analog Inputs:

32 differential, voltage-sensing inputs, direct-coupled > 10ohm impedance front panel connectors mate with LeCroy Model CK2232 Connector Kit (2 Required)

Full-Scale Range:

Bipolar Mode: -5 to +5 volts between minus and plus input
Monopolar Mode: 0 to +10 volts between minus and plus input

Common Mode Range:

5 volts (monopolar mode); -8 volts (bipolar model.

Common Mode Rejection Ratio:

60 dB.

Noise immunity:

1 kHz low pass filtering

Integral Non-linearity:

+/- 1/2 count.

ADC Resolution:

12 bits (+/-0.025% relative accuracy). Input source impedance of >0.5 Mohms is required for 1 bit accuracy over full range.

Temperature Coefficient:

Accuracy, 30 PPM/degC., linearity 20 PPM/degC.

Mode Selection:

On-board switch selects either Single Shot or Continuous Scan mode.

Conversion Time:

Continuous Scan Mode: continuously converted data always available for readout. Updated every 18 msec (550 usec/channel).

Single Shot Mode: 18 msec (550 usec/channel).

Readout Time

Readout may proceed at the fastest rate permitted by the CAMAC standard at any time.

Data:

The proper CAMAC function and ac!dressing scheme gates the 12 binary bits of the selected channel onto the R1 to R12 (2 0 to 2 11) Dataway bus lines MSB indicates polarity of + input with respect to -- input; remaining 11 hts indicate absolute value. (In monopolar option all bits indicate absolute value.)

CAMAC Commands:

Q: A Q = 1 response is generated in recognition of FjO1 and F(1} function for a valid "N" and "A," and F(2) for "N" during a readout of all 32 registers Any other condition will evoke no Q response (i,e., 0 = Q), including an a.:empt to read a 33rd word on F(2).

L: In the single scan mode only, a Look-At-Me signal is generated after all 32 inputs have been digitized until a module CLEAR LAM is disabled for the duration of N.

X: An X = 1 (Command Accepted) response is generated when a vs F, N, end A command is applied.

CAMAC Function Codes:

F(0) A(i); i = 0-15, read the data word from channel [i + 1) Requires N.
F(1) A(i); i = 0-15, read the data word from channel (i + 17). Requires N
F(2): Initiate readout address to zero, then read alt 32 registers successively starting with input 0 and progressing to input 31. Requires N and S2 Upon receipt of a 34th F2, a 0 = 0 response is given and the unit returns to Continuous Scan Mode. Facilitates DMA transfers.
F(9): Reset LAM.
F(25): initiates Single Scan of all channels beginning with channel 0. Requires N and S2. Note: It is recommended to "initiate" with F25 after power turn-on in Continuous Scan Mode.

Scan Trigger:

Logical "one" TTL pulse (> + 2.0 volts) of duration >=100 nsec applied to front-panel Lemo-type connector initiates single scan of all 32 channels beginning with Channel 0.

Packaging:

In conformance with CAMAC standard for nuclear modules (Esone Committee Report EUR 4100 and IEEE #583). RF-shields CAMAC #1 module.

Power Requirements:

+6 V at 700 mA
+24 V at 50 mA
-24V at 50 mA

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Specifications
Analog Inputs:	32 differential, voltage-sensing inputs, direct-coupled > 10ohm impedance front panel connectors mate with LeCroy Model CK2232 Connector Kit (2 Required)
Full-Scale Range:	Bipolar Mode: -5 to +5 volts between minus and plus input Monopolar Mode: 0 to +10 volts between minus and plus input
Common Mode Range:	5 volts (monopolar mode); -8 volts (bipolar model.
Common Mode Rejection Ratio:	60 dB.
Noise immunity:	1 kHz low pass filtering
Integral Non-linearity:	+/- 1/2 count.
ADC Resolution:	12 bits (+/-0.025% relative accuracy). Input source impedance of >0.5 Mohms is required for 1 bit accuracy over full range.
Temperature Coefficient:	Accuracy, 30 PPM/degC., linearity 20 PPM/degC.
Mode Selection:	On-board switch selects either Single Shot or Continuous Scan mode.
Conversion Time:	Continuous Scan Mode: continuously converted data always available for readout. Updated every 18 msec (550 usec/channel). Single Shot Mode: 18 msec (550 usec/channel).
Readout Time	Readout may proceed at the fastest rate permitted by the CAMAC standard at any time.
Data:	The proper CAMAC function and ac!dressing scheme gates the 12 binary bits of the selected channel onto the R1 to R12 (2 0 to 2 11) Dataway bus lines MSB indicates polarity of + input with respect to -- input; remaining 11 hts indicate absolute value. (In monopolar option all bits indicate absolute value.)
CAMAC Commands:	Q: A Q = 1 response is generated in recognition of FjO1 and F(1} function for a valid "N" and "A," and F(2) for "N" during a readout of all 32 registers Any other condition will evoke no Q response (i,e., 0 = Q), including an a.:empt to read a 33rd word on F(2). L: In the single scan mode only, a Look-At-Me signal is generated after all 32 inputs have been digitized until a module CLEAR LAM is disabled for the duration of N. X: An X = 1 (Command Accepted) response is generated when a vs F, N, end A command is applied.
CAMAC Function Codes:	F(0) A(i); i = 0-15, read the data word from channel [i + 1) Requires N. F(1) A(i); i = 0-15, read the data word from channel (i + 17). Requires N F(2): Initiate readout address to zero, then read alt 32 registers successively starting with input 0 and progressing to input 31. Requires N and S2 Upon receipt of a 34th F2, a 0 = 0 response is given and the unit returns to Continuous Scan Mode. Facilitates DMA transfers. F(9): Reset LAM. F(25): initiates Single Scan of all channels beginning with channel 0. Requires N and S2. Note: It is recommended to "initiate" with F25 after power turn-on in Continuous Scan Mode.
Scan Trigger:	Logical "one" TTL pulse (> + 2.0 volts) of duration >=100 nsec applied to front-panel Lemo-type connector initiates single scan of all 32 channels beginning with Channel 0.
Packaging:	In conformance with CAMAC standard for nuclear modules (Esone Committee Report EUR 4100 and IEEE #583). RF-shields CAMAC #1 module.
Power Requirements:	+6 V at 700 mA +24 V at 50 mA -24V at 50 mA