If you are currently developing or debugging a third-party pump controller interface, let me know which stage you are working on. I can provide explicit details on the , clarify the exact byte sequences for specific pump commands, or help troubleshoot hardware circuit designs for the active current loop interface.
For retrofitting older Gilbarco sites (Encore 300/500) without replacing dispensers, the new two-wire protocol converters are the only economical path.
| Command | Function | Typical Use | | :--- | :--- | :--- | | <SOH>01<Grade> | Authorize sale | Pre-auth for dollar/volume limit | | <SOH>02 | Price request | Poll current fuel price per grade | | <SOH>06 | Sale complete | End transaction, print receipt | | <SOH>07 | Reset/Pump off | Immediate stop flow | | <SOH>0R | Real-time status | Poll for sale volume, dollars, handle state | If you are currently developing or debugging a
Understanding the Gilbarco Dispenser Two-Wire Protocol for Third-Party Pump Controllers
The customer lifted the handle; awaiting authorization. | Command | Function | Typical Use |
Adopting the Two-Wire Protocol for third-party control offers tangible business and operational benefits:
The non-standard baud rate of 5787 bps presents a hurdle for modern microcontrollers (like STM32, ESP32, or NXP LPC chips). Standard UART fractional dividers often cannot match 5787 bps exactly, leading to framing errors. Developers must use a high-frequency crystal oscillator or utilize a dedicated programmable timer to generate an exact clock source for the UART peripheral. 2. Timing and Collision Avoidance Developers must use a high-frequency crystal oscillator or
45mA current loop (nominally between 30mA and 45mA). Logic States: Marking (Logic 1): Current flowing (Closed loop). Spacing (Logic 0): No current flowing (Open loop).
These converters generally do not translate the data "language"—they only make the physical connection. The third-party POS or controller must still implement the logical Gilbarco Two-Wire protocol to command the pump.