How Point-to-Point LoRa Replaces Expensive 4-20mA Current Loop Wiring in Industrial Applications

Introduction

In industrial settings—especially oilfields, water treatment plants, and manufacturing facilities—4-20mA current loopshave long been the standard for transmitting sensor data (pressure, temperature, flow). However, trenching and running wires for these loops is expensive, time-consuming, and inflexible.

Point-to-point LoRa wireless technology offers a cost-effective, reliable, and scalable alternative to wired 4-20mA loops. Unlike proprietary high-reliability radios (which are prohibitively expensive) or WiFi (which lacks range and interference resistance), LoRa provides long-range, low-power, interference-free communication at a fraction of the cost.

This article explores:

✅ Why trenching for 4-20mA loops is expensive and impractical

✅ Why traditional high-reliability radios are too costly

✅ How LoRa enables multiple wireless 4-20mA replacements without interference

✅ Real-world applications where LoRa outperforms wired solutions

1. The High Cost of Trenching & Installing 4-20mA Wired Loops

1.1 Labor & Material Expenses

• Trenching costs range from $10 to $50 per linear foot, depending on terrain and obstacles.
• Conduit, wire, and junction boxes add $2-$5 per foot in materials.
• Labor for installation, termination, and testing can exceed $100/hour for skilled electricians.

Example: A 1-mile (5,280 ft) 4-20mA loop could cost:

• Trenching: $52,800 – $264,000
• Materials: $10,560 – $26,400
• Labor: $50,000+Total: $100,000 – $340,000+

1.2 Maintenance & Downtime Risks

• Wire degradation from moisture, rodents, or chemical exposure leads to signal drift or failure.
• Locating and repairing breaks requires expensive diagnostic equipment and downtime.
• Expansion requires new trenching—making system upgrades slow and costly.

➡ LoRa eliminates these costs by replacing wires with wireless links.

2. Why Traditional High-Reliability Radios Are Too Expensive

Some industries use licensed-band radios (900MHz, 2.4GHz proprietary) for critical telemetry, but these come with major drawbacks:

2.1 High Hardware Costs

• Licensed-band radios (e.g., Motorola, FreeWave) cost $1,000 – $5,000 per node.
• LoRa modules (e.g., Semtech SX1276) cost $10 – $50 per node.

2.2 Recurring Spectrum Fees

• Licensed frequencies require annual FCC or regulatory fees (e.g., $5,000+ per year for 900MHz private bands).
• LoRa operates in free ISM bands (868MHz, 915MHz)—no licensing costs.

2.3 Limited Scalability

• Proprietary radios often max out at 10-50 nodes per gateway before congestion occurs.
• LoRa supports thousands of nodes per gateway using Adaptive Data Rate (ADR).

➡ LoRa provides industrial-grade reliability at consumer-grade prices.

3. How LoRa Enables Multiple Wireless 4-20mA Replacements Without Interference

3.1 Long-Range & Penetration (Up to 15+ km)

• Sub-GHz frequencies (868/915MHz) penetrate walls, foliage, and metal structures better than 2.4GHz WiFi.
• Ideal for oilfields, where sensors are spread across miles.

3.2 Chirp Spread Spectrum (CSS) Modulation

• LoRa’s unique modulation allows multiple signals to coexist without interference.
• Unlike WiFi (collision-prone) or FSK radios (limited channels), LoRa can handle hundreds of sensors in the same area.

3.3 Adaptive Data Rate (ADR) for Efficiency

• LoRaWAN automatically adjusts data rates based on signal strength.
• Close sensors transmit faster, while distant ones use lower data rates for extended range.

3.4 Frequency Agility (Avoiding Congestion)

• If interference is detected, LoRa shifts to a clear channel automatically.
• Non-LoRa 900MHz radios get stuck on a single frequency, leading to packet loss.

4. Real-World Applications: Where LoRa Outperforms Wired 4-20mA

4.1 Oil & Gas Well Monitoring

• Replacing wired pressure/temperature transmitters with LoRa-enabled 4-20mA transmitters.
• Savings: Eliminates $100,000+ in trenching per well pad.

4.2 Water & Wastewater Treatment Plants

• Wireless pH, flow, and level sensors communicate via LoRa instead of buried conduit.
• No more digging up pipes to repair broken wires.

4.3 Agricultural Irrigation Systems

• Soil moisture sensors transmit via LoRa, avoiding miles of trenching in fields.

5. Cost Comparison: LoRa vs. Wired 4-20mA vs. High-End Radios

➡ LoRa is the most cost-effective, scalable, and reliable alternative to wired 4-20mA loops.

Conclusion: Why Industries Are Switching to LoRa for 4-20mA Replacement

✅ Eliminates $100,000+ trenching costs per mile

✅ No recurring spectrum fees (unlike licensed radios)

✅ Handles hundreds of sensors without interference

✅ Long battery life (5-10 years on a single charge)

✅ Future-proof: Easily add new sensors without rewiring

Final Recommendation

If your facility relies on 4-20mA loops, switching to LoRa wireless can save 80%+ on installation and maintenance costs while improving reliability. Stop digging trenches—go wireless with LoRa today!