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 1 Hz to 5400 Hz.
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
+15 VDC at 30 mA.
-15 VDC at 20 mA.
+ 5 VDC at 10 mA w/digital outputs OFF.
Add up to 88 mA for all outputs ON.
The standard supply requires 120 VAC +/- 10% at 60 Hz.
