Signal Conditioning for Non-Standard Analog Signals
Need to measure a signal outside your control system’s standard input ranges?
Many real-world process signals don’t fit neatly into typical control system input ranges. Applications such as shunt-based current measurement, combustion and exhaust sensor monitoring, bipolar-to-unipolar signal conversion, and battery voltage monitoring often require reliable signal conditioning before the signal can be used by a PLC or other control equipment.
Standard PLC input cards from leading automation brands typically support ranges such as 0–10 V, ±10 V, 0–20 mA, and 4–20 mA. In practice, however, engineers often need to measure voltages and currents outside these ranges. That creates a clear need for signal conditioning that is accurate, stable, and easy to configure.
The Core Challenges (and How a Signal Converter Solves Them)
Preserve Small Signals
A high signal-to-noise ratio keeps low-level signals clean through the conditioning chain for better precision and confidence in the data.
Eliminate Ground Loops
An isolated input lets the measurement point float independently, removing offset from ground reference differences in noisy environments.
Maintain Stability
A low-drift design with simple scaling holds accuracy over time, reducing commissioning and recalibration effort.
Protect Against High Voltage
High working-voltage isolation (typically 250–300 V AC/DC) separates field signals from the control system and protects PLC input cards.
Scale to Your Range
Simple configuration of custom upper and lower ranges matches the signal to your application without sacrificing accuracy.
Easy Configuration
A front-mounted clip-on display makes programming, scaling, and diagnostics straightforward during setup and maintenance.
Solutions for Non-Standard Current and Voltage Signals
Built on years of hands-on application experience, the PR 4179, PR 4179B, and PR 4184 are designed to solve signal conversion challenges that standard PLC input cards cannot handle on their own. These universal signal converters combine flexibility, precision, and ease of setup in a compact DIN-rail design, with customer-programmable features accessed through a front-mounted clip-on display.
Product Comparison
| Specification | PR 4179 | PR 4179B | PR 4184 |
|---|---|---|---|
| Type | Universal AC/DC transmitter | Universal trip amplifier | Universal uni-/bipolar signal transmitter |
| Measures | AC current & voltage → DC | AC current & voltage → DC | DC voltage or current |
| Input range | AC current / voltage | AC current / voltage | ±300 VDC and ±100 mA |
| Output | 0–23 mA / ±23 mA or 0–10 V / ±10 V | Same as 4179 + relays | Bipolar / unipolar configurable |
| Response time | < 0.75 s | < 0.75 s | < 20 ms |
| Accuracy | Better than 0.3% | Better than 0.3% | Better than 0.05% of selected range |
| Relays | — | 2 × N.O. relays, 250 VAC/VDC | — |
| Auxiliary supply | — | — | > 16 V at 23 mA |
| Best for | AC-to-DC signal conversion | AC conversion + setpoint/alarm switching | Fast DC signals: torque, position, current, acceleration |
Specifications per PR electronics and subject to change. Confirm current specifications before ordering.
Explore PR electronics Signal Conditioning ProductsApplications
These devices are well suited for applications where non-standard current or voltage signals must be converted into stable, usable control signals.
Motor Load Monitoring
In applications such as crushers and grinders, motor current can be used as a reliable indicator of load. By measuring one phase through a matching current transformer and connecting it to the PR 4179, the signal can be scaled to a 4–20 mA output for a panel meter or control system.
Load is monitored locally on the panel meter, with secondary overload protection for increased safety.
Battery State-of-Charge Monitoring
In remote telemetry and control installations powered by solar-backed battery systems, continuous visibility into battery module health is essential. The PR 4184 can be used to monitor individual battery modules and convert each measured value into a stable signal for the control system. When monitoring multiple 55 V battery modules in a stack, several PR 4184 units can be installed together with PR 4511 communication interfaces to provide Modbus RTU communication to a PLC-based telemetry solution.
Better visibility into battery condition, less unplanned downtime, and proactive maintenance planning.
Why Choose PR 4179 and PR 4184?
The PR 4179 and PR 4184 give you a practical and reliable way to bring non-standard AC and DC signals into the ranges your PLC, control system, or monitoring equipment can actually use. Instead of working around the limitations of standard input cards, you gain accurate signal conversion, strong isolation, flexible scaling, and simpler integration across a wide range of industrial applications.
Whether you’re monitoring motor load, measuring battery module voltage, or conditioning low-level and high-potential DC signals, these converters help improve measurement confidence, protect valuable control hardware, and reduce time spent on setup and commissioning.
Let’s Talk About Your Project
Want to discuss whether PR electronics is right for your application? As a PR electronics distributor, Process Solutions Corp. can help you select and source the right signal conditioning solution for your needs.
Contact Us TodaySource: This article is adapted from “Signal conditioning for non-standard analog signals” by PR electronics (read the original). Process Solutions Corp. is an authorized distributor of PR electronics products. All product specifications are per PR electronics and subject to change — confirm current specifications before ordering.