We call the connection between H1 and HSE a bridge ; this application creates a standard network topology that you can see here: The bridges connect the H1 network to the high-speed Ethernet, converting data telegrams and data transfer rates depending on the direction of the transmission. H1 cards: These work as your interface with the FF devices. Here you can have redundant cards if you need the backup.
Power supply: Foundation Fieldbus can power more than one H1 segment. You can find redundant power supplies, intrinsic models, and also models with signal conditioners and segment terminators built-in. Signal conditioner: To provide robust communication, you need to condition the power supplies.
FF also adds inductance between the field devices and the power supply, protecting the signal from the low impedance of the power supplies and more. Segment terminator: The network requires one segment terminator at each end of the trunk.
The segment terminator matches the impedance of the cable and a balanced transmission line. You need no more than two terminators on the network. Wiring: The FieldComm Group provides specs for your wiring FF , but primarily you should have a shielded and twisted-pair cable. This cable can maximize network length and reduce signal reflections.
Device coupler or junction box: This unit will distribute the network to the spurs. It also operates as a point for maintenance, diagnostics, and circuit protection. Point-to-point or daisy-chain: This layout has all field devices connected to each in series. That means that one device will link to the next to the end of the network, using their own terminals to make these connections.
We provide software and hardware tools to help simplify the development process and provide the best chance of compliance with test specifications. Foundation Fieldbus. Home Technologies. Learn more. What is a flapper nozzle mechanism? High-Pressure Sensors. Related posts. Direct Acting Solenoid — How it works?
Since the cost of H1 cards and other segment hardware can be cost-prohibitive, being able to place more devices on a segment can save users a considerable amount.
Every fieldbus segment must be terminated at both ends for proper communication. If a segment is not terminated properly, communications errors from signal reflections may occur. In a segment, the last device coupler should contain the terminator, and all couplers between the last coupler and the H1 card should have their terminator switches set to off.
A frequent commissioning problem during startup is determining that terminators are correctly located. The instruments can behave erratically, drop off the segment mysteriously, and generally raise havoc—all because the terminations are not set properly. Diagnosing the problem often requires physically examining each device coupler to determine if the switches are set properly throughout the segment.
It automatically activates when the device coupler determines that it is the last fieldbus device coupler in the segment; if it is, it terminates the segment correctly.
If it is not the last device, it does not terminate the segment, since the downstream device coupler will assume that responsibility. No action—such as setting DIP switches—is necessary by the installation person to terminate a segment properly.
If a device coupler is disconnected from the segment accidentally or for maintenance, the Automatic Segment Termination detects the change, and terminates the segment at the proper device coupler. This allows the remaining devices on the segment to continue operation. Justifying Fieldbus :.
Fieldbus was initially justified by the considerable cost savings that resulted from using less wiring. Instead of running hundreds or thousands of wires, fieldbus often required only a few dozen segments or trunks.
In recent years, the savings from running cables has been offset by the high cost of fieldbus components, and the reluctance of many users to install all the instruments possible on a segment. Being forced to provide for short circuits, for example, limits the number of instruments. In other cases, when the full capability of a segment can be used, hardware cost savings become more realistic. The true advantage of fieldbus is its ability to diagnose equipment problems, cut maintenance costs, provide information for asset management, allow control at the device level, and allow the use of smart devices.
0コメント