MODEL 250 Fast 23-Bit Data Acquisition System

Specifications for Model 250

MODEL 250 Fast 23-Bit Data Acquisition System

Other precision data
acquisition products

zoom

download

Manual: .rtf .pdf .zip

Sample applications

Source code
(with sample applications)

TYPE

Sampling successive approximation converter with parallel computer interface

CHANNELS

6 differential, expandable to 96 differential

RESOLUTION

23 bits.

MAXIMUM DATA RATE

5400 samples/second (single-channel)
2125 samples/second (multi-channel)

LINEARITY

0.0004% of full scale

MONOTONICITY

22 bits typical

DIFFERENTIAL INPUT RANGE

+/-5.1 volts

DC COMMON MODE RANGE

+/-10.5 volts .

DC COMMON MODE REJECTION

-96 dB minimum.

CHANNEL SEPARATION

-96 dB minimum for 2125 Hz multi-channel scan

INPUT IMPEDANCE

10,000 megohms typical

OVERVOLTAGE PROTECTION

+/- 35 volts.

OFFSET ERROR

25 microvolts (after calibration)

GAIN ERROR

40 microvolts (after calibration).

WARM-UP PERIOD

30 minutes.

EFFECTIVE RESOLUTION

Effective resolution is defined as total resolution minus RMS noise in bits. It is 19.5 bits at 5 KHz. Programmable averaging provides better effective resolution at lower data rates. In AC mode, averaging reduces the inherent conversion noise. In DC mode, all noise sources can be averaged including noise on the input signal itself. For DC signals, averaging allows effective resolution approaching 23 bits at 80 samples/second.

OPERATING MODES

Can operate in polled or scanning mode. In polled mode, individual readings are transmitted on request. In scanning mode, a pre-defined scan is transmitted at a preset interval. Using external multiplexers, up to 96 channels can be sequentially scanned. Both polled and scanning modes offer track/hold and DC operation.

DATA RATE

Programmable, under 1Hz to 5400Hz

SELF-CALIBRATION

Extensive built-in self-calibration capabilities. Under software control, a 4095-point calibration will restore full accuracy.

PARALLEL INTERFACE

4-bit buffered interface with error checking. A bi-directional or high-speed parallel port is not required
A 6-foot cable is provided for use with an LPT port
Multiple Model 250s can be attached to a single parallel port using multiplexing hardware
Lawson Labs plans to have the buffered multiplexer ready for sale later in the year

DIGITAL INPUT/OUTPUT

8 inputs, contact closure or TTL or 5-volt CMOS logic compatible
8 latched digital outputs TTL or 5-volt CMOS logic compatible
4 latched outputs, compatible with Lawson Labs multiplexers and multiplexed amplifiers (Logic compatible, with pull-up resistors)

POWER CONSUMPTION

+15VDC at 30mA.
-15VDC at 20mA.
+5VDC at 10mA w/digital outputs OFF.
Add up to 88mA for all outputs ON
The standard supply requires 120VAC +/-10% at 60Hz

SIZE

5 x 6.5 x 1 inches board only
5.6 x 6.9 x 1.8 inches in standard enclosure
External power supply: 3 x 4.75 x 2.6 inches

WEIGHT

1 lb board only
3 lb in standard enclosure
3 lb external power supply

ENVIRONMENT

0 to 50° C, non-condensing.

HOME