1 GENERAL DESCRIPTION AND SPECIFICATIONS
This single-channel conditioner is for measurement of flow, rpm, and other phenome-
na that can be sensed by pulse transformer transducers with two-wire isolated wind-
ings (tachometer pickups, turbine flowmeters, etc.), transistor or logic-circuit drivers,
“zero-velocity” (true digital output) sensors, and similar
frequency-generating trans-
ducers
.
The 10A40 accepts a wide range of wave shapes and voltage levels, either grounded
or floating—though it is not recommended for measuring frequencies under 25 Hz
without special modification. The “Smart Schmitt” input threshold automatically
adjusts to accommodate signals from 10 mV to 200 V. Nominal ±5 V-DC excitation is
supplied for use with a “zero-velocity” sensor.
Capacitive coupling of 0.1 or 10 µF is provided for low-frequency inputs, to eliminate
false triggering by signal noise and/or any positive or negative DC offset that exists for
the frequency signal. A special trigger-level control guarantees reliable triggering
when the input is at the low end of the voltage range.
The System 10 Central Processor controls frequency-range selection and applies an
appropriately calculated scaling factor to each measurement, if desired, following initial
entry of a special
FREQUENCY CALIBRATION (FRQ) command (see Section 3.a,
below). This convenient “calculated” calibration technique can be used when the manu-
facturer-supplied full-scale rating of the frequency source (or the highest frequency
expected to be measured) is known. A precise 2.097152-MHz crystal frequency refer-
ence ensures accuracy of all calibrations, whether “absolute,” “calculated” (via the
FRQ
command), or “two-point” (“dead-weight”).
ADDITIONAL 10A40 SPECIFICATIONS
Input:
Type: Any AC or unipolar pulse signal, grounded or floating, irrespective of waveform
Threshold Level: Accommodates signals from 100 mV to 200 V
Frequency Ranges: From 10% to 100% of 250, 500, 1000, 2000, 4000, 8000, 16000, or
32000 Hz; automatically selected—on an individual channel basis—when the channel is
configured;
for the System 10 channel “type” code assigned to a 10A40 data chan-
nel, see Table 1, below
Excitation: Nominal 10 (i.e., ±5) V-DC; ±50 mA, maximum
Measurement Characteristics (per channel):
Normal-Mode Range
: ±200 V operating and without instrument damage
Common-Mode Range: ±50 V operating; ±100 V, without instrument damage
Common-Mode Rejection Ratio: At 60 Hz: -120 dB; at 1 kHz: -60 dB
Input Impedance: Differential: 400 kΩ; Common-Mode: 100 kΩ
(cont’d)
GENERAL DESCRIPTION AND SPECIFICATIONS 10A40.1
SYSTEM 10
ANALOG INPUT CARDS
1.E.2.10A40
MODEL 10A40
FREQUENCY INPUT
CONDITIONER CARD
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