Ultimate ATG Forecourt Controller Integration: BIR, DIM, and TDIM

A 5,000-gallon delivery rolls in while dispensers stay active. Without ATG forecourt controller integration, 120 gallons can slip into the reconciliation gap before anyone notices.

Most fuel sites still run the automatic tank gauge and the forecourt controller as separate systems. The ATG watches tanks underground. The controller handles dispensers and payments above ground.

This guide covers BIR, DIM, TDIM, and Allied controllers.

What Is ATG Integration and Why Does Every Fuel Site Need It?

ATG integration connects the tank gauge to the controller, giving operators real-time inventory, automated reconciliation, and leak response at the POS.

The ATG monitors tanks underground. A forecourt controller manages dispensers and payments above ground. Allied's What Is a Forecourt Controller article lays out the role.

Without integration, the site falls back to manual stick readings or separate console checks.

Integrated sites usually gain four immediate advantages:

• Real-time tank levels at the POS and back office
• Automated delivery reconciliation during live fuel drops
• Hourly variance alarms on inventory drift
• Leak alerts that can trigger dispenser shutdown

What Is Business Inventory Reconciliation (BIR)?

BIR is a Veeder-Root protocol that transmits tank inventory, delivery reports, alarm conditions, and leak test results from the ATG to the controller.

The Allied Electronics BIR DIM applications page confirms the integration path. BIR is a Veeder-Root protocol, not an industry-wide standard. It is not governed by Conexxus or PEI.

BIR data commonly includes:

• Current tank product level, temperature-compensated volume, and water level
• Delivery start and end events
• Delivery volume reconciliation
• Alarm conditions such as high level, low level, and leak detected
• Leak test results

Consider the reconciliation example: a 5,000-gallon delivery arrives while dispensers continue operating. The ATG records 120 gallons dispensed during the transfer window. BIR sends an adjusted delivery volume of 4,880 gallons to the controller, matching actual fuel received. Without BIR, that 120-gallon gap becomes a reconciliation dispute with the fuel supplier.

What Is a DIM (Dispenser Interface Module)?

A DIM (Dispenser Interface Module) is a hardware module that sits between the ATG and the forecourt controller, translating dispenser transaction data for reconciliation.

On a physical site, the DIM bridges the TLS console and the controller. It is the serial path for consoles that don't have Ethernet-based TDIM capability.

Older TLS-300 and TLS-350 consoles need a DIM because TDIM depends on Ethernet.

What Is a TDIM (TCP/IP DIM)?

A TDIM (TCP/IP DIM) uses the TLS-450PLUS Ethernet port as a virtual DIM, replacing the physical module with a TCP/IP connection to the controller.

The TLS-450PLUS Automatic Tank Gauge adds built-in Ethernet and removes the separate DIM module. Only ETH1 can be programmed as a TDIM. ETH2 does not support TDIM functionality. ETH1 is the port closest to the front of the TLS-450PLUS console.

Benefits of TDIM over a physical DIM:

• No DIM hardware cost
• Ethernet replaces serial cable runs
• Remote monitoring over the site IP network
• Better fit for multi-building sites where serial distance is a constraint

DIM vs TDIM: When Should You Use Each?

Use a hardware DIM for older TLS-300 and TLS-350 consoles or sites with existing serial wiring. Use TDIM for new TLS-450PLUS installations where Ethernet is available.

DIM fits legacy serial sites. TDIM fits new TLS-450PLUS Ethernet sites. The choice comes down to console generation and network layout.

How Do Allied NeXGen PRIME and AEGIS Connect to Veeder-Root ATGs?

Both Allied NeXGen PRIME and AEGIS controllers connect to Veeder-Root ATGs via serial RS-232 through a DIM module or Ethernet through TDIM on TLS-450PLUS ETH1.

The NeXGen PRIME forecourt controller and the AEGIS forecourt controller both support the BIR/DIM/TDIM path. The Veeder-Root partnership page confirms that compatibility. Allied has deployed over 52,000 interface devices worldwide.

DIM Integration Path (Serial)

A serial cable runs from the Allied controller to the DIM module, and the DIM connects to the TLS console. The crossover wiring uses pin 2 for RX, pin 3 for TX, and pin 5 for ground. The serial settings are 9600 baud, 8N1 (8 data bits, no parity, 1 stop bit).

TDIM Integration Path (Ethernet)

An Ethernet cable runs from the Allied controller to the TLS-450PLUS ETH1 port. Both sides need the IP address and port configured. Remember: only ETH1 supports TDIM.

Once connected, both controllers receive BIR data for:

• Real-time tank inventory at the POS
• Delivery reconciliation during live fuel drops
• Hourly variance alarms
• Leak detection that can trigger dispenser shutdown

What Do Operators Gain from ATG Integration?

Operators gain real-time fuel inventory at the POS, automated delivery reconciliation, hourly variance alarms, leak detection interlocks, and EPA compliance documentation.

The biggest change is visibility. Tank data moves from a standalone console in the equipment room to the POS and back office, where it can inform purchasing, scheduling, and safety decisions. The EPA underground storage tank regulations make that visibility a compliance requirement, not a convenience.

Automated reconciliation eliminates manual math. In the 5,000-gallon delivery example, 120 gallons dispensed during the transfer becomes an adjusted delivery of 4,880 gallons. That adjustment happens automatically through BIR, preventing reconciliation disputes with fuel suppliers.

Other gains stack quickly:

• Hourly variance tracking catches slow leaks that manual readings miss
• Leak detection alerts can shut dispensers down before contaminated fuel reaches customers
• Integrated logs create the UST audit trail regulators require
• Tank gauge parts, probes, and accessories are available through Allied's petroleum parts superstore

Common ATG Integration Issues and Troubleshooting

The most common ATG integration failures are serial cable faults, TDIM port misconfiguration, BIR communication timeouts, and IP address conflicts.

Serial Cable Faults

Verify RS-232 crossover wiring: pin 2 is RX, pin 3 is TX, and pin 5 is ground. Confirm 9600 baud and 8N1 on both the controller and TLS console. Test cable continuity with a multimeter if the connection drops intermittently.

TDIM Port Misconfiguration

Confirm the Ethernet cable is on ETH1, not ETH2. Only ETH1, the port closest to the front of the TLS-450PLUS console, supports TDIM. Plugging into ETH2 is the most common field mistake.

BIR Communication Timeout

Match baud settings on both ends. Inspect the cable path for damage. Verify the DIM module has power and is connected.

DIM Capacity Exceeded

Match site dispenser count to DIM model capacity. Running five dispensers on a CDIM (3 inputs) requires upgrading to an LVDIM or MDIM (12 inputs each).

IP Address Conflicts (TDIM)

The TLS-450PLUS ETH1 address must sit on the same subnet as the controller but must not conflict with other network devices. Static IP assignment avoids DHCP surprises.

Preventive Maintenance

• Verify BIR communication in controller logs on a regular schedule
• Keep probe calibration current
• Inspect DIM modules in extreme heat or cold
• Check firmware compatibility between the TLS console and controller

Allied's Forecourt Controller Maintenance guide covers the full preventive schedule.

Frequently Asked Questions About ATG Forecourt Controller Integration

These are the questions petroleum IT staff and equipment dealers ask most about connecting automatic tank gauges to forecourt controllers.

Conclusion

ATG forecourt controller integration turns two isolated systems into a unified forecourt where tank data flows directly to the POS. The key takeaways:

• BIR protocol removes the data silo between underground tank monitoring and above-ground forecourt operations
• DIM hardware modules serve legacy TLS-300 and TLS-350 sites; TDIM over TCP/IP is the preferred path for TLS-450PLUS installations
• ETH1 is the only TLS-450PLUS port that can be programmed as TDIM, and plugging into ETH2 is the most common field mistake
• Allied NeXGen PRIME and AEGIS controllers support both serial (DIM) and TCP/IP (TDIM) integration paths, backed by a documented Veeder-Root partnership