ATG (Automatic Tank Gauge) Systems Deep Dive
The ATG is the nerve center of fuel facility monitoring - providing real-time inventory, leak detection, and compliance data. Understanding ATG consoles, probes, and alarms is essential for every petroleum technician.
TLS-350 End-of-Life Notice
Veeder-Root announced end-of-sale/support after 2025 for the TLS-350. Replacement parts will no longer be produced. Sites with TLS-350 consoles should plan upgrades to TLS-450PLUS or TLS4 series. The good news: existing probes and sensors are backward compatible with new consoles.
Market Leader
Veeder-Root
TLS-450 Max Probes
64 (256 exp)
Probe Accuracy
±0.1"
Leak Test Rate
0.2 GPH
Console Comparison
| Feature | TLS-350 | TLS-450PLUS | TLS4 | EVO 550 |
|---|---|---|---|---|
| Status | End-of-life (2025) | Active - Flagship | Active - Mid-range | Active |
| Max Probes | 32 | 64 (256 w/expansion) | 12 (32 w/expansion) | 36 |
| Interface | LCD + keypad | Color touchscreen | Color touchscreen | 7" color touchscreen |
| Remote Access | No | Yes (Plus View app) | Yes (app) | Yes (FFS PRO Connect) |
| CSLD | Optional module | Built-in | Built-in | Built-in |
| Cybersecurity | Basic | Enhanced (encryption, roles) | Enhanced | User roles, audit trails |
| Best For | Legacy sites (upgrade needed) | Large/networked sites | Mid-size sites | Independent retailers |
Console Models
TLS-350
Veeder-Root
LCD text display with membrane keypad
- • Modular design with input cards
- • Inventory monitoring
- • In-tank leak detection (0.2 gph)
- • Alarm notifications
Industry workhorse since 1990s. End-of-sale after 2025 - parts no longer produced.
TLS-450PLUS
Veeder-Root
Large color touchscreen
- • Plus View mobile/web app for remote monitoring
- • Enhanced cybersecurity (encrypted access, user roles)
- • Up to 256 inputs with expansion boxes
- • Pressurized line leak detection (PLLD)
Modern successor to TLS-350. Lower total cost of ownership via remote support.
TLS4
Veeder-Root
Color touchscreen
- • Expandable to 32 probes with expansion box
- • Up to 20 relay outputs, 16 inputs
- • Same software as TLS-450
- • Multi-language interface
Mid-size sites. More compact than TLS-450PLUS.
TLS4B
Veeder-Root
Color touchscreen
- • Basic configuration - no expansion capability
- • Same software interface as TLS4
- • Compact footprint
- • Mobile app compatible
Small sites only (few tanks). "B" = Basic.
EVO 550
Franklin Fueling Systems
7-inch color touchscreen
- • FFS PRO Connect platform for remote access
- • Intuitive icon-driven interface
- • User accounts with roles and audit trails
- • 3 years data backup in memory
Common in independent and smaller retail sites.
EVO 5000
Franklin Fueling Systems
7-inch color touchscreen
- • Same as EVO 550 with higher capacity
- • Large site capability
- • FFS PRO Connect platform
- • Auto tank calibration
High-capacity alternative to TLS-450PLUS.
TS-550 / TS-5000
Franklin Fueling Systems
LCD text display with M1-M4 menu keys
- • Inventory monitoring
- • In-tank leak detection
- • Report generation
- • Alarm management
Legacy INCON-branded consoles. Being replaced by EVO series.
UST vs AST Applications
| Aspect | Underground (UST) | Aboveground (AST) |
|---|---|---|
| Probe Selection | Standard 4-10 ft probes for typical horizontal tanks | Mag-FLEX tall tank probes (up to 50+ ft) for vertical ASTs |
| Environmental Exposure | Underground = stable temperature | Exposed to weather - wider temperature swings affect readings |
| Leak Detection | 0.2 gph tests often mandated for compliance | Often single-wall with dike - different monitoring approach |
| Interstitial Monitoring | Standard with double-wall tanks | Double-wall ASTs use similar sensors; single-wall use dike sensors |
| Overfill Prevention | Mechanical overfill valve + ATG high alarm | Often electronic high-level switch with local siren/strobe |
| Thermal Effects | Minimal - ground-insulated | Significant - volume swings from day/night temperature changes |
| Physical Security | Protected underground | Accessible - may need tamper-proofing on sensors |
Frequently Asked Questions
What is an ATG (Automatic Tank Gauge)?
An ATG is an electronic monitoring system for fuel storage tanks. It uses probes inside the tank to continuously measure fuel level, water level, and temperature. The console displays real-time inventory, generates alarms for abnormal conditions (leaks, water, overfill), and performs automatic leak detection tests. ATGs are required for EPA compliance at UST facilities.
What is the difference between TLS-350 and TLS-450PLUS?
The TLS-350 is the legacy Veeder-Root console (LCD + keypad, no remote access) being phased out after 2025. The TLS-450PLUS is the modern replacement with a color touchscreen, remote monitoring via mobile app, enhanced cybersecurity, and advanced leak detection features. The TLS-450PLUS is backward compatible with existing probes and sensors, so field hardware does not need replacement during upgrade.
How does a magnetostrictive probe work?
A magnetostrictive probe sends an electrical pulse down a tensioned wire inside a sealed tube. Floats with magnets ride on the tube - one for fuel level, one for water. When the pulse reaches each magnet, it creates a torsional wave that reflects back. By precisely timing the return, the system calculates the position of each float, giving accurate fuel and water levels. This technology provides ±0.1 inch accuracy and enables precise leak detection.
What is the difference between brine-filled and dry interstitial monitoring?
Brine-filled interstice uses a glycol/water solution in the space between double tank walls. A drop in brine level indicates inner wall leak (fuel displaced brine); a rise indicates outer wall leak (groundwater entering). Dry interstice uses no liquid - a sensor at the bottom detects any liquid that appears. Brine systems can identify which wall leaked; dry systems require investigation to determine source.
Why is my ATG showing a High Water alarm?
A High Water alarm means water has accumulated in the tank above the set limit (often 2 inches). Common causes include: water entering through a loose fill cap during rain, condensation buildup over time, or groundwater leaking through a tank wall breach. Action: investigate the source, have the water pumped out by a fuel service company, and repair any entry points. High water can damage customer vehicles and indicates a potential compliance issue.
How often should ATG probes be calibrated?
ATG probes should be verified annually during compliance inspections. Modern systems like the TLS-450PLUS have AccuChart auto-calibration that learns the tank profile during deliveries. Manual calibration is typically done when: a probe is replaced, after tank modification, or if readings consistently differ from stick measurements by more than 0.5 inches. Always document calibration in compliance records.