SCMVAS
V oltage Attenuator System
Description
The SCMVAS (Signal Conditioning Modular Voltage Attenuator System) is an
analog signal conditioning system designed to safely monitor and accurately
measure voltage potentials up to 460VAC (1300V peak-to-peak). These highlevel voltages are typically found in industrial applications such as induction
heaters or electric-motor drive controllers. The system reduces the input signal
to a level suitable for interface to data acquisition systems, while at the same
time providing various filter characteristics and 1500Vrms isolation (Figure 1).
For each channel of analog input, an attenuator module, SCMVAS-Mnnn,
pre-conditions the signal which is then filtered, isolated, and converted to a
high-level voltage output using an SCM5B30-07 or SCM5B40-07 module. The
SCM5B40-07 module with a 10kHz bandwidth is recommended for common 50/
60Hz signals low in harmonics where the user is interested in measuring only
AC voltage. The SCM5B30-07 module is used for low frequency AC signals
below 4Hz. For signals comprised of harmonics or noncoherent content, the
SCM5B33 True RMS Input module is recommended. Use of this module
provides a DC output that is directly related to input signal power, or the RMS
(Root Mean Square) value, allowing true RMS representation of input signals
ranging from pulses to complex nonperiodic waveforms. The attenuator and
signal conditioning modules have excellent stability over time and do not require
recalibration. Overall system accuracy is ±0.06%.
Input signal connections to the SCMVAS-Mnnn attenuator module are made
using a pluggable terminal block for ease of system assembly and reconfiguration.
For safety purposes, the terminal block has a cover over the screws and there
are no other exposed high-voltage points on the SCMVAS-Mnnn series modules, SCM5B30-07 or SCM5B40-07 module, or the mounting backpanel.
Isolated Analog Signal Conditioning Products
Features
• Accepts High Voltage Signals up to 460VAC
(1300V Peak-to-Peak)
• 5 or 10 Volt Output for A/D Systems
• 1500Vrms Transformer Isolation
• True 3-Way Isolation
• Up to 160dB CMR
• ±0.06% Accuracy
• Panel or DIN Rail Mounting Options
• Approvals Pending
SCM5B
SCM5B
The SCMVAS system has two specially designed backpanels for mounting the
attenuator and signal conditioning modules. The SCMVAS-PB8 high density, 8channel backpanel (Figures 2, 3) can be panel mounted or DIN rail mounted and
provides the conditioned output signal on screw terminal blocks. Jumpers are
provided on each channel to optionally connect or isolate each module’s I/O
Common from other channel’s I/O Common and/or Power Common. The
SCMVAS-PB16 (Figures 4, 5) has 16 channels of analog I/O simultaneously
available to high-speed data acquisition (ADC) boards through a 26-conductor
ribbon cable. Refer to the SCMPB01 Data Sheet and Application Note AN502
in this catalog for recommended ground connections and host system interfaces. Both the SCMVAS-PB8 and SCMVAS-PB16 backpanels can be mounted
on the SCMXRK-002 19-inch metal rack.
Figure 1: SCMVAS Schematic
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SCM5B30/40-07
Isolated Analog Voltage Input Modules
Isolated Analog Signal Conditioning Products
SCM5B
Specifications
Typical at TA=+25°C and +5V power
Module SCM5B30-07 SCM5B40-07
Input Range –1.0V to +1.0V *
Input Bias Current ±0.5nA *
Input Resistance
Normal 50MΩ *
Power Off 40kΩ *
Overload 40kΩ *
Input Protection
Continuous 240Vrms max *
Transient ANSI/IEEE C37.90.1 *
CMV, Input to Output
Continuous 1500Vrms max *
Transient ANSI/IEEE C37.90.1 *
CMR (50 or 60Hz) 160dB 100dB
NMR 95dB at 50Hz, 90dB at 60Hz 120dB per Decade
(1)
Accuracy
Linearity ±0.005% Span ±0.01% Span
Stability
Input Offset ±20mV/°C *
Output Offset ±20mV/°C *
Gain ±25ppm/°C *
Noise
Input, DC to 10Hz 2µVrms *
Output, 100kHz 200µVrms 2mVp-p
Bandwidth, -3dB 4Hz 10kHz
Response Time 0.2s 35µs
(to 90% final value)
±0.03% Span *
above 10kHz
Ordering Information
(3)
Model
SCM5B30-07 V Isolation Module, ±5V Output, 4Hz Bandwidth
SCM5B40-07 V Isolation Module, ±5V Output, 10kHz Bandwidth
SCM5B30-07D V Isolation Module, ±10V Output, 4Hz Bandwidth
SCM5B40-07D V Isolation Module, ±10V Output, 10kHz Bandwidth
SCM5B33-02 True RMS Module, 0 to 5VDC Output
SCM5B33-02B True RMS Module, 0 to 1mADC Output
SCM5B33-02C True RMS Module, 4 to 20mADC Output
SCM5B33-02D True RMS Module, 0 to 10VDC Output
SCM5B33-02E True RMS Module, 0 to 20mADC Output
Description
Output Range –5V to +5V *
Output Resistance 50Ω *
Output Protection Continuous short to ground *
Output Selection Time 6.0µS at C
(to ±1mV of Vout)
Output Current Limit ±8mA *
Output Enable Control
Max Logic “0” +0.8V *
Min Logic “1” +2.4V *
Max Logic “1” +36V *
Input Current “0,1” 0.5µA *
Power Supply Voltage +5VDC ±5% *
Power Supply Current 30mA *
Power Supply Sensitivity ±200µV/% RTI
Mechanical Dimensions 2.28"x 2.26"x 0.60" *
Environmental
Operating Temp. Range –40°C to +85°C *
ATEX Group II, Cat. 3 –20°C to +40°C *
Storage Temp. Range –40°C to +85°C *
Relative Humidity 0 to 95% noncondensing *
Emissions EN61000-6-4 ISM, Group 1 *
Radiated, Conducted Class A *
Immunity EN61000-6-2 ISM, Group 1 *
RF Performance A ±0.5% Span Error *
ESD,EFT
(–10V to +10V, D model versions)
= 0 to 2000pF *
load
(2)
(58mm x 57mm x 15mm)
Performance B *
*
NOTES:
(1) Includes linearity, hysteresis and repeatability.
(2) RTI = Referenced To Input.
(3) SCM5B33 modules allow connection of input signals up to 300Vrms without SCMVAS
attenuator modules. Consult SCM5B33 datasheet for details.
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For information call 800-444-7644
SCMVAS-Mnnn
High Voltage Attenuator Modules
Specifications
Module
Input Range ±100Vpeak to ±700Vpeak (70VAC to 500VAC)
Input Voltage Maximum ±750Vpeak
Input Resistance 10MΩ
Accuracy ±0.03%
Stability ±50ppm/°C
Typical at TA=+25°C
SCMVAS-Mnnn
Isolated Analog Signal Conditioning Products
SCM5B
SCM5B
Output Range ±1V
Output Resistance <100kΩ
Mechanical Dimensions 1.70"x 1.98"x 0.69"
(44mm x 51mm x 18mm)
Environmental
Operating Temp. Range –40°C to +85°C
ATEX Group II, Category 3 –20°C to +40°C
Storage Temp. Range –40°C to +85°C
Relative Humidity 0 to 95% noncondensing
Accessories
Model Description
SCMVAS-PB8 Backpanel, 8-Channel
SCMVAS-PB8D Backpanel, 8-Channel, DIN Rail Mount
SCMVAS-PB16 Backpanel, 16-Channel
SCMVAS-PB16D Backpanel, 16-Channel, DIN Rail Mount
Ordering Information
Model Description Input Range with V Isolation Module Input Range with True RMS Module
SCMVAS-M100 Attenuator Module ±100V Input (70VAC) ±141V Input (100VAC)
SCMVAS-M200 Attenuator Module ±200V Input (141VAC) ±283V Input (200VAC)
SCMVAS-M300 Attenuator Module ±300V Input (212VAC) ±424V Input (300VAC)
SCMVAS-M400 Attenuator Module ±400V Input (282VAC) ±566V Input (400VAC)
SCMVAS-M500 Attenuator Module ±500V Input (353VAC) ±707V Input (500VAC)
SCMVAS-M600 Attenuator Module ±600V Input (424VAC) Not Available
SCMVAS-M650 Attenuator Module ±650V Input (460VAC) Not Available
SCMVAS-M700 Attenuator Module ±700V Input (495VAC) Not Available
SCMVAS-MPT Attenuator Module, Pass-Thru 1-to-1
Figure 2: SCMVAS-PB8 Analog I/O Backpanel
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Isolated Analog Signal Conditioning Products
SCM5B
Figure 3: SCMVAS-PB8 Schematic
Figure 4: SCMVAS-PB16 Analog I/O Backpanel
46
For information call 800-444-7644
Isolated Analog Signal Conditioning Products
SCM5B
SCM5B
Figure 5: SCMVAS-PB16 Schematic
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