SCM5B33
Isolated True RMS Input Modules
FEATURES
DESCRIPTION
● INTERFACES RMS VOLTAGE (0 – 300V) OR RMS CURRENT (0 – 5A)
Each SCM5B33 True RMS input module provides a single channel of AC
input which is converted to its True RMS dc value, filtered, isolated,
amplified, and converted to a standard process voltage or current output
(Figure 1).
● DESIGNED FOR STANDARD OPERATION WITH FREQUENCIES OF
45HZ TO 1000HZ (EXTENDED RANGE TO 20Khz)
● COMPATIBLE WITH STANDARD CURRENT AND POTENTIAL
The SCM5B modules are designed with a completely isolated computer side
circuit which can be floated to ±50V from Power Common, pin 16. This
complete isolation means that no connection is required between I/O
Common and Power Common for proper operation of the output switch. If
desired,theoutputswitchcanbeturnedoncontinuouslybysimplyconnecting
pin 22, the Read-Enable pin to I/O Common, pin 19.
TRANSFORMERS
● INDUSTRY STANDARD OUTPUTS OF EITHER 0-1MA, 0-20mA,
4-20MA, 0-5V OR 0-10VDC
● ±0.25% FACTORY CALIBRATED ACCURACY (ACCURACY CLASS
0.2)
The field voltage or current input signal is processed through a pre-amplifier
and RMS converter on the field side of the isolation barrier. The converted dc
signalisthenchoppedbyaproprietarychoppercircuitandtransferredacross
the transformer isolation barrier, suppressing transmission of common
modespikesandsurges.Thecomputersidecircuitryreconstructs,filtersand
converts the signal to industry standard outputs. Modules are powered from
+5VDC, ±5%.
● 1500 VRMS CONTINUOUS TRANSFORMER BASED ISOLATION
● INPUT OVERLOAD PROTECTED TO 480V MAX (PEAK AC & DC) OR
10A RMS CONTINUOUS
● ANSI/IEEE C37.90.1-1989 TRANSIENT PROTECTION
● REGULATORY COMPLIANCE (TO BE DETERMINED)
For current output models an external loop supply is required having a
compliancevoltageof14to48VDC.Connection,withseriesload,isbetween
Pin 20 (+) and Pin 19 (-).
4
Pre-Amp,
Conversion
+EXC
Isochopper™
20
4
LPF
VOUT or IOUT
Amplifier
**
Surge
Suppression
and
AC Source +In
6
Pat Pending
3
2
1
IIN
*
19
22
5
3
I/O Common
RD EN\
Protection
+V
–V
–In
**
–EXC
Isolated
Computer-Side
Power
Backpanel
Term Block
17
16
+V
+5V
Isolated
Field-Side
Power
Power
Oscillator
–V
* Current Input Models Only
Add Jumpers for Current Input Modules
(provided with SCM5B33-06, 07)
Power Common
**
FIGURE 1. SCM5B33 Block Diagram.
®
Call 800-444-7644
DATAFORTH
For Information and Assistance
A Burr- Brown Company
48