KS3021 1-Channel Analog Input Terminal 4-20 mA Differential

Product Overview

The KS3021 (KS3021) is a high-precision 1-channel analog input terminal designed for the processing of standard 4 to 20 mA industrial signals. Utilizing advanced differential input technology, this terminal is specifically engineered to eliminate ground loop interference and suppress common-mode noise, making it an ideal choice for long-distance sensor deployments in harsh electromagnetic environments. In sectors such as chemical processing, water treatment, and HVAC control, the KS3021 provides the reliability needed for critical telemetry. With a fast 1 ms conversion time and 12-bit resolution, it ensures that dynamic process variables are captured with high fidelity. The "KS" designation signifies a pluggable wiring level, allowing for rapid module replacement without disturbing the existing field instrumentation wiring.

Technical Configuration

The KS3021 integrates a differential input stage with an internal resistance of 80 Ω plus a 0.7 V diode voltage drop. It supports a maximum common-mode voltage of 35 V, providing significant robustness against potential shifts between the sensor ground and the control system ground. The terminal is powered entirely via the internal K-bus, drawing a typical current of 60 mA, which simplifies cabinet power distribution by eliminating the need for external 24 VDC power contact connections. For safety-critical or hazardous area applications, the module features 500 V electrical isolation between the K-bus and the signal level, and carries ATEX Ex nA IIC T4 Gc certification for use in Zone 2 explosive atmospheres.

Technical Specifications

Technical FAQs

What is the primary advantage of the pluggable wiring level on the KS3021?

The KS-series terminals feature a detachable wiring plug. This allows maintenance personnel to replace a faulty module by simply unplugging the pre-wired terminal block and inserting it into a new unit. This eliminates the risk of wiring errors and significantly reduces Mean Time to Repair (MTTR) in 24/7 production environments.

How does the differential input handle signal noise compared to single-ended inputs?

The differential input measures the voltage difference between two signal lines rather than measuring one line against a common ground. This configuration effectively cancels out "common-mode" noise that affects both wires equally, which is essential for maintaining signal integrity in areas with high motor interference or variable frequency drives.

Is this terminal suitable for use in hazardous locations?

Yes, the KS3021 is ATEX certified with the marking II 3 G Ex nA IIC T4 Gc. It is approved for use in Zone 2 environments, provided it is installed in an appropriately rated enclosure that meets the requirements of the industrial site safety standards.

Engineering & Installation Guide

• Wiring Precision and Stripping: Use solid or stranded conductors with a cross-section of 0.08 to 1.5 mm squared (AWG 28-16). Ensure a precise stripping length of 9 to 10 mm. Use a small flat-head screwdriver to actuate the spring clamp; the pluggable block ensures that once wired, the connections remain vibration-proof according to EN 60068 standards.

• Grounding and Shielding: To maximize the benefits of the differential input, use shielded twisted-pair cables. The shield should be connected to a functional earth (FE) point at the terminal entry using a shield bracket to divert high-frequency interference away from the internal 12-bit A/D converter.

• K-bus Power Management: Since the KS3021 draws its power solely from the K-bus (60 mA), always verify the total power budget of your Bus Coupler. If the total K-bus current of all attached terminals exceeds the coupler's limit (e.g., 500 mA or 1000 mA), a K-bus refresh terminal must be added to the segment.