The SCM7B32 and SCM7B33 are isolated process signal conditioning modules for current and voltage inputs, respectively. The SCM7B32 accepts 4-20mA or 0-20mA inputs and converts them internally to a high-level voltage output; the SCM7B33 accepts +1V to +5V or 0 to +5V voltage inputs, or 4-20mA with an external 250Ω resistor. Both provide 0 to +5V or 0 to +10V outputs, feature 1500Vrms transformer isolation, 105dB CMRR, and ±0.03% typical accuracy. They operate from a 14-35VDC supply, consume 12mA, and have a 100Hz bandwidth with a 5ms step response. The modules are housed in a 2.13" x 1.705" x 0.605" package and are designed for DIN-rail mounting. They are certified to CSA C/US, CE, ATEX, ANSI/IEEE C37.90.1, and RoHS III standards, with continuous input protection to 120Vrms and an operating temperature range of -40°C to +85°C.
The SCM7B32 current input modules accept input signals in the 4-20mA or 0- 20mA ranges from the field and provide a high-level output to the process control system. Current to voltage conversion occurs internal to the module, which is factory calibrated to ensure the highest accuracy.
SCM7B33 voltage input modules accept input signals in the +1V to +5V or 0 to +5V ranges from the field and provide a high-level output to the process control system. As an alternative, the SCM7B33 can be used with an external 250 ohm resistor (Dataforth SCM7BXR1 or equivalent), to accept input signals in the 4-20mA or 0-20mA ranges. Using the external sense resistor allows the module to be removed without disrupting the current loop. All SCM7B33s are shipped with a SCM7BXR1 resistor.
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.
After the initial field-side filtering (conversion-SCM7B32 only), the 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.
Modules accept a wide 14 - 35VDC power supply range (+24VDC nominal). Their compact packages (2.13"x1.705"x0.605"
| Dataforth Corporation | |
|---|---|
| Product Category | Data Acquisition |
| Product Number | SCM7B32/33-xx |
| Product Name | SCM7B32/33 Isolated Process Current/Voltage Input Module |
| Data Acquisition | Input Module; Input/Output Module |
| Form Factor | Rack Mount; DIN Rail |
| Outputs | Analog Voltage Output |
| Filter / Amplifier | Amplifier; Filter |
| Agency Approval | CSA, CE |
