scxi1127-8.pdf

(236 KB) Pobierz
SCXI High-Voltage
Multiplexer/Matrix Module
SCXI-1127, SCXI-1128
For applications involving
Thermocouples
RTDs
Thermistors
Voltages
Current
Resistance
Software configurable
Random scanning
Multiplexer modes (with SCXI-1331)
1-wire (64 channels)
2-wire (32 channels)
4-wire (16 channels)
Matrix modes (2-wire)
8x4 (with SCXI-1132)
mV to 300 VDC/300 V rms
(250 V rms for SCXI-1128)
Up to 768x1 (1-wire) multiplexer in single
SCXI chassis
Scanner Advanced and External
Trigger
signals for use with external
measurement devices
Maximum scanning speed
100 channels/s for SCXI-1127
1200 channels/s for SCXI-1128
Voltage installation category II
Application Software
LabVIEW
Measurement Studio
IVI-compliant instrument driver
Windows 2000/NT/Me/9x
Solutions
Production test and ATE
High-channel count applications
Battery testing
Power supply testing
Automotive test
Module
Function
Description
Switching Specifications
SCXI-1127
Multiplexer/Matrix
32-channel, mechanical relay
300 V rms /300 VDC
EXPRESS
CODES
SCXI-1128
Multiplexer/Matrix
32-channel, solid-state relay
250 V rms /300 VDC
Table 1. SCXI-1127 and SCXI-1128 Switch Specifications (see page 449 for detailed specifications)
For information or to
buy products online,
visit ni.com/catalog
and enter:
Overview
The National Instruments SCXI-1127 (electromechanical relay) and
SCXI-1128 (Solid-State Relay) are devices that function as multiplexer or
matrix modules. As a multiplexer, they can operate in different multiplexing
modes, such as 1-wire for large channel-count systems, 2-wire for
differential pair systems, or 4-wire for resistive measurements including RTDs
and low-resistance measurements. With the SCXI-1332 front-mounting
terminal block, the SCXI-1127 and SCXI-1128 become an 4x8 2-wire matrix.
See Tables 2 and 3 for a complete list of possible configurations.
Expanding the multiplexer or matrix channel count is as easy as adding
additional modules. Analog signals are passed between modules
through the high-voltage backplane, and in most cases you can expand
your channels without complicated wiring. A matrix expansion cable is
available for your convenience. The SCXI-1127 is designed to work well
with both low and high-voltage levels. For low-voltage measurements,
such as thermocouples, the SCXI-1127 uses relays with low thermal offset
to ensure accurate measurements. Providing low contact resistance as
well, the SCXI-1127 is ideal for switching low resistance and RTD
measurements. These same relays can handle up to 300 V rms at 300 mA,
so the module can measure line voltages worldwide. The SCXI-1128 uses
SSR relays that provide very high scanning speed. They can switch up to
300 VDC/250 V rms . With no moving mechanical parts, the relays also
maintain a long life expectancy.
Description
Figure 1 is a block diagram of the
SCXI-1127 and SCXI-1128. The major
functions of the modules are described in
the following paragraphs.
scxi1127
scxi1128
Modes of Operation
The SCXI-1127 and SCXI-1128 are
completely software configurable to
operate as a multiplexer/scanner, matrix, or
independent switch bank.
Digitizer/Chassis
System
HVAB
Controller
Size
Chassis
Accessory
SCXI-1000, SCXI-1000DC,
776575-571 or
Single Chassis
PXI-1010
776575-572
or First Chassis
776575-581 or
in a Multichassis
SCXI-1001
NI 4021
776575-582
System
NI 4060
PXI-1011
185444-OR18 1
SCXI-1000
Additional
776575-57M
SCXI-1000DC
Chassis
SCXI-1001
776575-58M
The PXI-1011 includes a built-in HVAB accessory; however, you need to order an HV8 to BAN4 connector cable.
Table 2. Recommended System Configuration for the SCXI-1127
1
National Instruments
Tel: (512) 794-0100 • Fax: (512) 683-9300 • info@ni.com • ni.com
431
819885350.051.png 819885350.061.png 819885350.064.png 819885350.065.png 819885350.001.png 819885350.002.png 819885350.003.png 819885350.004.png 819885350.005.png 819885350.006.png
SCXI High-Voltage
Multiplexer/Matrix Module
AISENSE
CJTEMP+, CJTEMP—
CJ
Relay
2
9
OUT0 Return to
Front Connector
2 Wire Mode
1 Wire Mode
OUT0
OUT1
OUT2
OUT3
CONTCJTEMP
COM0+
HVAB0+
Relay
Channel
Bank 1
CH+ (0:7)
CH— (0:7)
COM0—
HVAB0—
9
9
5
9
CONT (0-7)
8
OUT1 Return to
Front Connector
9
9
Relay
Channel
Bank 2
COM1+
HVAB1+
CH+ (8:15)
CH— (8:15)
HVAB1—
COM1—
6
9
HVAB2+
CH+ (0:31)
CH— (0:31)
OUT2 Return to
Front Connector
HVAB2—
CONT (8-15)
8
HVAB3+
Relay
Channel
Bank 3
COM2+
HVAB3—
9
CH+ (16:23)
CH— (16:23)
COM2—
7
9
9
CONT (16-23)
9
OUT3 Return to
Front Connector
COM3+
Relay
Channel
Bank 4
CH+ (24:31)
CH— (24:31)
COM3—
9
8
2
2
4
6
6
4
8
11
8
9
Drive
Circuitry and
Glue Logic
Drive
Circuitry
Safety Isolation
Controlling
Drive from FPGA
Controlling
Drive from FPGA
Digital Interface
and Control
(FPGA)
11
CONTCJTEMP,CONT(0-31)
SCANADV
EXTRIGIN
33
SCXIBus
Interface
2
2
9
Calibration EEPROM
9
3
Figure 1. Block Diagram of the SCXI-1127 and SCXI-1128
Multiplexer/Scanning
The SCXI-1127 and SCXI-1128 include a flexible random scanning
architecture to reduce overall data acquisition and test time. You can
control scans through hardware timing or software timing. For hardware-
timed applications, a scan list is downloaded into a 512-element memory
device on each module. The multiplexer state is then controlled by the
trigger lines of a scanning digital multimeter (DMM), such as the
NI 4060. The trigger lines, which are available at the front connector
of the SCXI-1127 and SCXI-1128, are also connected to the SCXI
backplane for multimodule applications. For applications where scan
timing is not critical, the SCXI-1127 and SCXI-1128 also offer software
controlled acquisition operations. You can configure the SCXI-1127
and SCXI-1128 in several different multiplexer/scanner configurations.
The 1-wire and 2-wire modes are designed for measuring/sourcing
voltage or 2-wire resistance measurements. In 2-wire mode, you can
solder resistors into pads inside the SCXI-1127 and SCXI-1128 to
perform current measurements or current-loop monitoring.
For improved measurement accuracy of low-voltage signals, such as
those from thermocouples or low resistance devices, such as RTDs,
configure the SCXI-1127 and SCXI-1128 in 4-wire mode for 4-wire
resistance measurements. The SCXI-1128 is the recommended choice for
low-power applications requiring high scanning speeds, or long
switch life. For low-voltage and resistance measurements, the SCXI-1127
is the recommended choice because of its low contact resistance and
low thermal EMF. You can also configure the SCXI-1127 and SCXI-1128 to
route excitation (current or voltage) from an external supply through two
of the four wires. While the SCXI-1127 and SCXI-1128 do not supply
excitation, other devices, such as NI 4060 DMMs, can supply these signals.
Matrix
Configured as a matrix, the SCXI-1127 and SCXI-1128 become a
general-purpose signal router. The 64 lines of the SCXI-1127 and
SCXI-1128 form a two-dimensional array of rows and columns. Through
software, you can control the matrix to connect any row(s) to any
column(s). The SCXI-1127 and SCXI-1128 offer several different 2-wire
and 4-wire matrix mode configurations. The SCXI-1332 terminal block
automatically configures the SCXI-1127 for 4x8, 2-wire matrix mode. All
other matrix configurations require the SCXI-1331 general-purpose
terminal block, additional user wiring, and the use of the SCXI-1127 and
SCXI-1128 in independent mode. For applications requiring matrices
larger than 4x8, use the matrix expansion cable accessories described
on page 447. Insert these cables between two SCXI-1332 terminal
blocks to automatically connect rows or columns together of two or
more SCXI-1127 modules. Each cable carries four differential lines.
432
National Instruments
Tel: (512) 794-0100 • Fax: (512) 683-9300 • info@ni.com • ni.com
819885350.007.png 819885350.008.png 819885350.009.png 819885350.010.png 819885350.011.png 819885350.012.png 819885350.013.png 819885350.014.png 819885350.015.png 819885350.016.png 819885350.017.png 819885350.018.png 819885350.019.png 819885350.020.png 819885350.021.png 819885350.022.png 819885350.023.png 819885350.024.png 819885350.025.png 819885350.026.png 819885350.027.png 819885350.028.png 819885350.029.png 819885350.030.png 819885350.031.png 819885350.032.png 819885350.033.png 819885350.034.png 819885350.035.png 819885350.036.png 819885350.037.png 819885350.038.png 819885350.039.png 819885350.040.png 819885350.041.png 819885350.042.png 819885350.043.png 819885350.044.png 819885350.045.png 819885350.046.png 819885350.047.png 819885350.048.png 819885350.049.png 819885350.050.png 819885350.052.png
SCXI High-Voltage
Multiplexer/Matrix Module
Signal Connections
Sensor, signal, and sources connect to the SCXI-1127 and SCXI-1128
through screw terminals on the SCXI-1331 and SCXI-1332. The SCXI-1331
is a general-purpose front-mounting terminal block giving you access to
each of the 64 relay lines of the SCXI-1127 and SCXI-1128. It also has
terminals for external trigger signals as well as the HVAB analog signals.
The SCXI-1332 converts the SCXI-1127 and SCXI-1128 into an 8x4 matrix.
By automatically connecting the necessary wires for this configuration,
this terminal block saves you time. With the matrix expansion cable, you
can easily expand the dimensions of your matrix system by connecting
the rows and columns of different matrix modules. The SCXI-1331
includes cold-junction compensation sensors for use with thermocouples.
See the terminal block descriptions on page 445 for more information.
Therefore, to expand a 4x8 matrix to an 8x8 matrix, you will need two
matrix expansion cables to connect the 8 columns. However, if you
wanted to expand a 4x8 matrix to a 4x16 matrix, you would only need
one matrix expansion cable to connect the four rows.
Independent
Configured as independent switch banks with software, you can
control the state of any relay on the SCXI-1127 and SCXI-1128. Use this
mode for custom applications, such as using the SCXI-1127 in 8x2,
8x1, 16x1, 16x2 matrix configurations.
Terminal Block
Type
CJ Sensor
Special Functions
Page
General purpose
Screw terminals
SCXI-1331
multiplexing and
445
front-mounting
switch configuration
Software
All National Instruments switch modules are shipped with NI-SWITCH
software. NI-SWITCH is an IVI-compliant instrument driver that exports
the complete functionality of the switches through an easy-to-use
interface. The instrument driver API is interchangeable with equivalent
National Instruments switch modules to ensure a scaleable system
design where you can reuse the software between systems. The driver
works with National Instruments LabVIEW and Measurement Studio,
and Microsoft Visual Basic and Visual C++.
Screw terminals
8 x 4 matrix (2-wire)
SCXI-1332
–
446
front-mounting
configuration
Table 3. Terminal Blocks for the SCXI-1127 and SCXI-1128
Analog Bus and Switch Controller
The SCXI-1127 and SCXI-1128 can be used with special rear adapters
to create a high-voltage analog bus (HVAB), separate from the
SCXIbus. While similar in functionality to the SCXIbus, this high-voltage
bus can switch both high-voltage and low-voltage signals to an
external device without compromising the integrity of the chassis.
However, you do not need an analog bus for systems using the PXI-1011
chassis because it is built in.
For the analog bus, you must choose the SCXI-1357 (4-slot chassis) or
SCXI-1358 (12-slot chassis) high-voltage analog bus (HVAB) kit. For
multichassis systems, select the appropriate analog bus for the first
chassis following the guidelines above. Then, select the appropriate
additional kits to interconnect chassis – SCXI-1357 HVAB multichassis
expansion kit (4-slot) or the SCXI-1358 HVAB multichassis expansion kit
(12-slot). Multichassis kits include 1 m cables for interconnecting chassis.
The National Instruments SCXI switching system controller is the NI 4021.
It connects to the analog bus via a SH9MD-AUX connector cable that
delivers the timing/triggering signals and programs each SCXI module.
However, NI 4060 DMM customers should use their DMM to control an
SCXI switching system as the DMM incorporates the same controller
functionality as the NI 4021. The NI 4060 DMM plugs directly into the
HVAB backplane via two cables, the SH9MD-AUX cable and the
HV8-BAN4 cable, which connects the DMM I/O to the HVAB signals.
For third-party devices, the analog bus and timing signals are also
routed to the front of each SCXI-1127 and SCXI-1128.
If you are using a National Instruments DAQ device to control SCXI
signal conditioning modules and would like to complement your
system with SCXI switching modules, you do not need a separate switch
controller. Your DAQ device will control the switching modules. You may
still use the HVAB to connect the switch modules. For systems
employing only third-party instruments, use the NI 4021 with the
appropriate HVAB accessory to control your switching system.
See page 449 for detailed specifications.
Ordering Information
SCXI-1127 ........................................................776572-27
SCXI-1128 ........................................................776572-28
Includes switch module and NI-SWITCH instrument driver.
Extended warranty
and value added services .................................page 880
See page 443 for accessory and cable information.
National Instruments
Tel: (512) 794-0100 • Fax: (512) 683-9300 • info@ni.com • ni.com
433
 
819885350.053.png 819885350.054.png 819885350.055.png 819885350.056.png 819885350.057.png 819885350.058.png 819885350.059.png 819885350.060.png 819885350.062.png 819885350.063.png
 

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin