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Casimiro Lurten

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Aug 3, 2024, 7:20:20 PM8/3/24

to pisrickferrang

What is Gilbarco Two Wire Protocol and How Does It Work?

Gilbarco Two Wire Protocol is a communication interface for connecting fuel pumps with Gilbarco Two Wire controllers. It is a proprietary protocol developed by Gilbarco Inc., a leading provider of fuel dispensing and point-of-sale systems for the petroleum industry.

The protocol uses two wires to transmit and receive data between the pump and the controller. The data is encoded using a Manchester code, which means that each bit is represented by a transition from high to low or low to high voltage. The protocol supports up to 32 pumps on a single controller, and each pump has a unique address ranging from 1 to 32.

The protocol operates in a master-slave mode, where the controller is the master and the pumps are the slaves. The controller initiates the communication by sending a request message to a specific pump address. The request message consists of a start bit, an address byte, a command byte, an optional data byte, and an end bit. The pump responds with an acknowledgment message, which consists of a start bit, an address byte, an acknowledgment byte, an optional data byte, and an end bit. The acknowledgment byte indicates whether the pump accepted or rejected the command, and the data byte contains additional information depending on the command.

Some of the commands that the controller can send to the pumps are:

Reset: This command resets the pump and clears any errors.

Status: This command requests the current status of the pump, such as idle, busy, authorized, dispensing, etc.

Authorize: This command authorizes the pump to start dispensing fuel.

Volume: This command requests the current volume dispensed by the pump.

Totalizer: This command requests the total volume dispensed by the pump since the last reset.

The protocol also supports broadcast messages, where the controller can send a command to all pumps at once. For example, the controller can send a reset command to all pumps by using address 0.

Gilbarco Two Wire Protocol is a simple and reliable way of communicating with fuel pumps. It allows the controller to monitor and control the pumps remotely, and provides feedback on the pump status and performance.

One of the advantages of Gilbarco Two Wire Protocol is that it requires only two wires to connect the pumps and the controller. This reduces the cost and complexity of the wiring and installation. It also makes the system more robust and resistant to noise and interference.

Another advantage of Gilbarco Two Wire Protocol is that it is compatible with various types of fuel pumps, such as mechanical, electronic, or hybrid pumps. The protocol can handle different pump features, such as preset, blend, or multi-product dispensing. The protocol can also support different units of measurement, such as liters, gallons, or cubic meters.

However, Gilbarco Two Wire Protocol also has some limitations. One of them is that it has a low data rate of 1200 bits per second. This means that the communication between the pumps and the controller can be slow and inefficient. It also limits the amount of data that can be transmitted or received.

Another limitation of Gilbarco Two Wire Protocol is that it is a proprietary protocol that is not standardized or widely adopted. This means that it is not compatible with other controllers or pumps from different manufacturers. It also makes it difficult to integrate with other systems or devices, such as payment terminals, loyalty programs, or cloud services.