鈥?/div>
16-bit resolution
0.025% FS accuracy
Continuous background BIT testing with Excitation and Signal loss detection
Self-calibrating. Does not require removal for calibration
360 Hz to 10 kHz operation
Autoranging input between 2.0 and 28 Vrms
12, 8, and 4-channel versions available
Optional programmable reference excitation
Transformer isolated
LATCH feature
Compensates for
鹵60擄
phase shift
No adjustments or trimming required
Part Number, S/N, Date Code, and Revision in permanent memory
DESCRIPTION:
This high-density intelligent DSP-based card incorporates up to twelve (12) separate transformer isolated
programmable LVDT/RVDT-to-Digital tracking converters with extensive diagnostics, and optional programmable
excitation supply. Instead of buying cards that are set for specific inputs, the uniqueness of this design makes it
possible to order our standard card that auto-ranges between 2.0 and 28 volts. Operating frequency between 400 Hz
and 10 kHz can be specified. Each chanel is programmable for either 2 wire or 3,4 wire inputs. For 2 wire inputs, the
output is computed as A/B (where A is the LVDT output and B is the excitation) and is expressed as % FS. For 3 or
4-wire devices, the output is computed as A-B/A+B and is expressed as %FS. This ratiometric technique assures
that the output will change only when the LVDT position changes and will ignore excitation voltage variations. The
LATCH feature permits the user to read all channels at the same time. Reading will unlatch that channel. The
converters utilize a Type II servo loop processing technique that enables tracking, at full accuracy, up to the specified
maximum rate. Intermediate transparent latches, on all data and velocity outputs, guarantee that current valid data is
always available for any channel, without affecting the tracking performance of the converters. The optional on鈭抌oard
excitation is field programmable. To simplify logistics, Part Number, S/N, Date Code, and Revision are stored in
permanent memory locations.
This board incorporates major diagnostics that offer substantial improvements to system reliability because user is
alerted to channel malfunction. Three different tests (one on-line and two off-line) can be selected
:
The D2 Test initiates automatic background BIT testing. Each channel is checked over the programmed Signal
range to a measuring accuracy 0.1% FS, and each Signal and Excitation is monitored. Results are available in
registers. The testing is totally transparent to the user, requires no external programming, has no effect on the
standard operation of this card and can be enabled or disabled via the bus.
The D3 Test, if enabled, starts an initiated BIT test that disconnects all channels from the outside world and connects
them across an internal stimulus that generates and measures multiple voltages to a test accuracy of 0.1%FS.
External excitation is not required. Results can be read from registers. The testing requires no external programming
and can be initiated or terminated via the bus.
Apex Signal,
A Division of NAI, Inc.
170 Wilbur Place, Bohemia, NY, 11716,USA
631.567.1100/631.567.1823(fax)
www.naii.com
/ e-mail:sales@naii.com
1-31-01
Code:OVGU1
S 77 LD1 A001 REV B 1.2
Page 1 of 7
1
2
3
4
5
6
7
