Each SCM7B34/34N RTD input module accepts a single channel of 100 ohm Platinum (a = 0.00385) or 120 ohm Nickel (a = 0.00672) RTD input and produces an input voltage in response to a low-level current excitation. The input signal is filtered, isolated, amplified, linearized, and converted to a high-level analog voltage for output to the process control system.

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 field side of the isolation barrier; four are on the process control system side.

In response to the low-level current excitation signal, the RTD input 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 and filtered for process control system output.

Linearization is achieved by creating a non-linear transfer function through the module itself. This non-linear transfer function is configured at the factory and is designed to be equal and opposite to the specific RTD non-linearity. Lead compensation is achieved by matching two current paths thus cancelling the effects of lead resistance.

Modules accept a wide 14 - 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.
  • Interfaces to 100 Ohm Platinum or 120 Ohm Nickel RTDS
  • Provides 250µA RTD Excitation Current
  • Linearizes RTD Signal Response
  • Provides High-Level Voltage Outputs
  • 1500Vrms Transformer Isolation
  • Accuracy, ±0.05% to ±0.15% of Span Typical
  • Nonconformity, ±0.025% to ±0.07% of Span Typical
  • ANSI/IEEE C37.90.1 Transient Protection
  • Input Protected to 120Vrms Continuous
  • Noise, 500µV Peak (5MHz), 250µV RMS (100kHz)
  • CMRR, up to 160dB
  • NMR, up to 85dB
  • Easy DIN Rail Mounting
  • CSA Certified, FM Approved
  • CE and ATEX Compliant
Isolated Linearized 2- Or 3-Wire RTD Input Modules

SCM7B34/34N Devices


Part Number Input ConfigurationRTD TypeInput RangeOutput RangeMechanical Format
2 & 3 Wire 100 Ohm Platinum -100 to 100 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum -100 to 100 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum -100 to 100 (°C) 0 to +10 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 100 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 100 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 100 (°C) 0 to +10 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 200 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 200 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 200 (°C) 0 to +10 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 600 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 600 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum 0 to 600 (°C) 0 to +10 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum -50 to 350 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum -50 to 350 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 100 Ohm Platinum -50 to 350 (°C) 0 to +10 V Modular plug-in-board
2 & 3 Wire 120 Ohm Nickel 0 to 300 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 120 Ohm Nickel 0 to 300 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 120 Ohm Nickel 0 to 300 (°C) 0 to +10 V Modular plug-in-board
2 & 3 Wire 120 Ohm Nickel 0 to 200 (°C) +1 to +5 V Modular plug-in-board
2 & 3 Wire 120 Ohm Nickel 0 to 200 (°C) 0 to +5 V Modular plug-in-board
2 & 3 Wire 120 Ohm Nickel 0 to 200 (°C) 0 to +10 V Modular plug-in-board

Frequently Asked Questions


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

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.

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

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

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.

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.

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.
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Model NumberInput RangeOutput RangeBandwidthSensor TypeStatus*Comments
SCM7B34-03-1621
0 to +200C+1V TO +5V3HZ100 OHM PLATINUM RTDPRSame as SCM7B34-03 with 20mA output current
SCM7B34-1366
0 TO 150C+1 TO +5V3HZ100 OHM PLATINUM RTDQUaccuracy -/+0.15%max, -/+0.1% typical
SCM7B34-1374
0 TO 150C+1 TO +5V3HZ100 OHM PLATINUM RTDQUsame as 7B34-1366
SCM7B34-1416
-50C TO +150C0V TO 10V3Hz2 - 3 WIRE RTDQU 
SCM7B34-1500
-100C TO +200C0V TO 10V10Hz100 OHM PLATINUM RTDQU 
SCM7B34-1527
-51C TO +176C0V TO 5V3Hz200 OHM PLATINUM RTDPR 
SCM7B34-1631
-300F TO +300F+1V TO +5V3Hz100 OHM PLATINUM RTDPRMinimum output load 200 Ohm
SCM7B34-1649
-50C TO +350C+1V TO +5V3Hz100 OHM PLATINUM RTDPRMinimum output load 200 Ohm
SCM7B34-1693
0C TO +200C0V TO +10V3HZ50 OHM PLATINUM RTDPRAlpha = 0.00392
SCM7B34-1756
-200 TO +200C0V TO +10V3HZ100 OHM PLATINUM RTDPR 
SCM7B34-1796
39 Ohm TO 104 Ohm0V TO +10V3HZRESISTANCE INPUTPROutput Voltage is linear with respect to Input Resistance
SCM7B34-1797
78 Ohm TO 208 Ohm0V TO +10V3HZRESISTANCE INPUTPROutput Voltage is linear with respect to Input Resistance
* ... Status Codes: PR = Production, PT = Prototypes, QU = Quoted