SCM7B39 process current modules accept high-level signals from the process control system and provide either 0 to 20mA or 4 to 20mA current to the field.

These modules incorporate a five-pole filtering approach to maximize both time and frequency response by taking advantage of both Thomson (Bessel) and Butterworth characteristics. One pole of the filter is on the process control system side of the isolation barrier, and the other four poles are on the field side.

After the initial process control system side filtering, the signal is chopped by a proprietary chopper circuit and transferred across the transformer isolation barrier, suppressing transmission of common mode spikes and surges. The signal is then reconstructed, filtered, and converted to a process current for output to the field.

Modules accept a wide 18 - 35VDC power supply range (+24VDC nominal). Their compact packages (2.13"x1.705"x0.605" max) save space and are ideal for high channel density applications. They are designed for easy DIN rail mounting using any of the "-DIN" backpanels.
  • Accepts High-Level Voltage Input
  • Provides 4-20mA or 0-20mA Current Output
  • 1500Vrms Transformer Isolation
  • Accuracy, ±0.03% of Span Typical, ±0.1% Max
  • ANSI/IEEE C37.90.1 Transient Protection
  • Output Protected to 120Vrms Continuous
  • Noise, 46µA Peak (5MHz), 4µA RMS (100kHz)
  • CMRR, 110dB
  • 80dB Per Decade of Attenuation Above 100Hz
  • Easy DIN Rail Mounting
  • CSA Certified, FM Approved
  • CE and ATEX Compliant
Isolated Process Current Output Modules

SCM7B39 Devices


Part Number Input RangeOutput RangeMechanical FormatIsolation VoltageIsolation Type
+1 to +5 V 4 to 20 mA Modular plug-in-board 1500 Vrms Transformer 2-way
0 to +10 V 0 to 20 mA Modular plug-in-board 1500 Vrms Transformer 2-way
0 to +10 V 4 to 20 mA Modular plug-in-board 1500 Vrms Transformer 2-way
4 to 20 mA 4 to 20 mA Modular plug-in-board 1500 Vrms Transformer 2-way



Frequently Asked Questions


Can SCM5B modules be hot swapped?
Not just SCM5B modules, but any signal conditioning module series and MAQ20 I/O modules can be hot swapped. A minimal amount of signal settling time may result, but there will be no damage to the device.

Can Dataforth provide calibration reports for modules I purchased?
Yes we can provide calibration reports for the modules that you purchased.

You can either
a) visit https://www.dataforth.com/TestDataReport.aspx to search for Test Report Datasheets by Serial Number or
b) you can send us a list of model numbers and their serial numbers to support@dataforth.com

Is the calibration of Dataforth modules traceable to NIST standards?
Yes, calibration of Dataforth modules is traceable to NIST standards.

Analog Devices announced a last time buy and discontinuance of their signal conditioning modules. Can I replace them with Dataforth signal conditioning modules?
Yes, in general, Dataforth signal conditioning modules are a direct replacement for all Analog Devices signal conditioning modules. e.g. "SCM5B35-xx: Linearized 4-Wire RTD Input Modules" will replace Analog Devices "5B35: Isolated 4 Wire RTD Input Signal Conditioning Module".

Please note that Dataforth signal conditioning modules are RoHS II compliant.

If I purchase a backplane with no CJC, will I still be able to use modules that require the CJC enable jumper to be installed?
Yes. Backplanes with no CJC will still come with the CJC enable installed on the backplane.

Where can I find the MTBF of my module?
Information on MTBF for SCM5B, SCM7B, 8B and DSCA is available on our website. Please see application note AN802 for more details. Application notes can be found under the "Literature" tab on the top navigation bar.

For SCM7B22 modules when I give LabVIEW (or other DAQ software) an output command, I get no output from the backpanel, why?
That’s because the SCM7B22 and the SCM7B39 are output modules, are connected the reverse of input modules, they have their inputs on the system side (power supply side) of the backpanel. They provide their output on the isolated field side of the backpanel.

Keywords/Phrases: 7B, 7B module, 7B output module, 7B22, 7B39

What does "Response time, 90% span" mean on the datasheet for my module?
Normally, a response time figure refers to how quickly a module's output can "respond" to a change in the input signal. "Response time, 90% span" refers to how fast a module can adjust its output when a step signal is applied at the input, where the magnitude of this step input is 90% of the input span of the module.

If the input range of my signal conditioner is -1V to +1V and the output range is 0 to 10V, does this mean that it ignores polarity?
A signal conditioner with these I/O ranges does not mean that the module ignores the polarity of your voltage input. The output of voltage input modules are scaled linearly, meaning an input of -1V would correspond to an output of 0V, an input of 0V would correspond to an output of 5V, an input of +1V would correspond to an output of 10V, and so on.

How does the load resistance of a module affect the noise at the output?
Noise at the output of a module is independent of load resistance.

How do I convert an RMS voltage to its corresponding peak voltage?
To convert an RMS voltage to its corresponding peak voltage, you simply take the RMS voltage value and multiply it by the square root of 2, or roughly 1.414.

For example, 1500Vrms corresponds to a peak voltage of 1500 * 1.414 = 2121 Vp

What does it mean when an input module has for example a 3kHz bandwidth?
A 3kHz bandwidth on an input module means it can accept voltages from DC to 3000Hz. Any frequency higher than that and the signal will start to be attenuated by the filter at the input.

Is the SCMXPRT-003 DIN rail mountable?
The SCMXPRT-001 has an option for DIN rail mounting (part number: SCMXPRT-001D) but the SCMXPRT-003 does not. Instead, it can be mounted on the SCMXRK-002 which is a 19 inch metal rack for mounting the SCMXPRT-003 as well as various Dataforth backpanels and the SCMXIF interface board.

Due to resource constraints on my computer, I'm unable to open the three dimensional CAD models provided on your website. Does Dataforth provide two demensional CAD models for download as well?
Two dimensional CAD models can be generated upon customer request. Please contact Customer Service for assistance.

Can Dataforth analog modules be used in high vibration environments? If so, what type of testing or certification was completed?
SCM5B, SCM7B, 8B SensorLex, and DSCA modules are well suited for use in high vibration environments. These modules and their associated accessories have undergone testing for random vibration, shock, and swept sine wave vibration. Details of each of these testing methods are provided below:

Random Vibration (Operating):
○ MIL-STD 202G, Method 214A, Condition 1
- Frequency Range: 50-2000Hz, flat spectrum
- Vibration Intensity: 7.56 Grms
- Duration: 10min/axis (X, Y, Z)

Shock (Operating):
○ MIL-STD-810F, Method 516.5
- Pulse Shape: Sawtooth
- Test Level: 30G
- Duration 11ms
- Orientation: +/-X, +/-Y, +/-Z

Swept Sine Vibration (Operating)
○ MIL-STD-810G, Method 514.6, modified
- Frequency Range: 10-2000Hz
- Vibration Intensity: 5Gp-p
- Sweep Rate: 1 octave/min
- Orientation: X, Y, Z

Declaration of conformity for the above-listed tests can be provided upon customer request. Please contact customer service if a copy of the declaration is needed.
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Model NumberInput UnitsInput RangeOutput UnitsOutput RangeBandwidthSensor TypeStatus*Comments
SCM7B39-1257
mA+4mA TO +20mAmA+4mA TO +20mA100HZCURRENT OUTPUTPRInput high Z when output loop open
SCM7B39-1368
V0V TO +5VmA0mA TO +1mA100HZCURRENT OUTPUTQU0 TO 13Kohm LOAD, 50M ohm Rin
SCM7B39-1373
mA+4mA TO +20mAmA+4mA TO +20mA100HZCURRENT OUTPUTQU250 OHM LOAD
SCM7B39-1808
V0V TO +10VmA+4mA TO +20mA100HZCURRENT OUTPUTPRSame as SCM7B39-03, without encapsulant and top label
* ... Status Codes: PR = Production, PT = Prototypes, QU = Quoted

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