Two profiles. The same drive can use either one over the same network. Even when the configured process-data size is identical, the meaning of the words can change. That is what makes this comparison worth writing down. Nothing visibly breaks when you pick the wrong one. The bus goes green, the PLC exchanges data, the drive accepts a… Read More: PROFIdrive vs ABB Drives Profile: Key Differences »
One parameter decides how your PLC talks to an ACS880 over PROFIBUS. It is 51.05 Profile. Not 51.02. That one is the node address, and it gets confused with the profile setting constantly — including in some vendor quick-start guides that use the label “Protocol/Profile” for 51.02. On an ACS880 with an FPBA-01, node address is 51.02 and… Read More: ACS880 PROFIBUS DP Profiles: How to Choose the Right 51.05… »
Most comparisons of these two treat them as rivals picking a fight over the same job. That framing gets the engineering wrong, and it gets one important fact wrong too. BACnet defines LonTalk as one of its own data link layers. Clause 11 of the BACnet standard specifies how BACnet messages ride on the LonTalk protocol. They are… Read More: LonWorks vs BACnet: How the Two Data Models Differ »
The power line channel is the one that fails for reasons nobody wrote down. A surge arrester goes in on the same board. A lighting retrofit lands on the same circuit. Both are perfectly good electrical work, and both can take the network down. ISO/IEC 14908-3 is unusually direct about this. It declines to specify the medium at… Read More: LonWorks Power Line: The 125-140 kHz Channel Explained »
Free topology is the reason people put up with LonWorks wiring. Bus, star, loop, or any mix of them, on one pair, with one termination you can put anywhere. No daisy-chain discipline, no polarity to get right. It isn’t free of rules. It has distance limits, a termination that has to be the right value, and a power… Read More: LonWorks Twisted Pair Wiring: Free Topology, Distances and Link Power »
A Modbus register is sixteen bits and nothing else. What those bits mean lives in a document somebody emailed you. A LonWorks network variable carries its own type. Two devices that agree on the type exchange a temperature without anyone deciding whether it’s tenths of a degree. That difference is the reason the protocol exists, and it’s also… Read More: LonWorks Network Variables: Selectors, Bindings, Aliases and Polls »
Pick the wrong service type and the network still works — until it doesn’t. Under light load everything delivers. Under load, the acknowledged multicast you specified starts eating the channel it needs, and the symptom looks like a hardware fault. ISO/IEC 14908-1 gives you four services. This is what each one actually does on the wire, when to… Read More: LonTalk Service Types: Acknowledged, Request/Response, Repeated and Unacknowledged »
Every LonTalk packet carries both a source and a destination address, and both live in the same header. There is no separate layer-2 addressing underneath — the standard folds routing and naming into one address field. Get the structure of that field straight and most of the network’s limits, quirks, and failure modes stop being mysterious. This is… Read More: LonTalk Addressing: Domain, Subnet, Node, Group and Neuron ID »
Walk into a plant room and you will see three names on the same equipment. LonWorks on the panel label. LonTalk in the manual. ISO/IEC 14908 in the submittal package. They are not three protocols. LonWorks is the platform — chips, transceivers, tools, devices. LonTalk is the protocol those devices speak. ISO/IEC 14908 is the published standard that… Read More: LonWorks Protocol: LonTalk, ISO/IEC 14908, and How the Network Actually… »
Above the tool Two holding registers come back as 17142 and 58982. The vendor manual says the value is a float. It does not say in which order the two registers go. That is the whole problem. The Modbus specification defines a 16-bit register and nothing larger, so every device that reports a 32-bit float had to invent… Read More: Modbus Float Converter — 32-Bit Register Word Order Tool »