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I'd never heard of NMEA either. So I Googled it. First .pdf hit is the The NMEA 0183 Protocol. 28 pages. An important note page 1: "NMEA 0183 is a voluntary industry standard, first released in March of 1983. It has been updated from time to time; the latest release, currently (August...

If the PLC master is addressing slave #3 and the slave's node ID address is #1, then the slave's Rx LED will likely flash because the slave 'sees' the incoming message. But the slave will not respond because it is slave #3 and the message is addressed to slave #1.

An I/P (eye to P) is a current(I)-to-pressure(P) transducer. If the input side of the transducer is Modbus/RTU over RS-485, then don't you need a Modbus/P transducer; a Modbus pneumatic transducer? (in the absence of I, typically a 4-20mA current loop signal) There are tens of thousands...

Is the gas monitor controller a Modbus master/client or a Modbus slave/server? It warrants investigating which box plays which Modbus role and confirming that the respective functionality for that role resides in the box at each end.

>8 bits/word, no parity and 1 stop bit is the default config for serial comms. I suspect that the site Moderators would post any Modbus specification updates or changes, so I just checked and the "MODBUS over Serial Line Specification and Implementation Guide V1.02", dated 2006, still has...

1. A problem when just working with a Modbus data value can be the lack of knowing that communications has failed, not realizing that fact and continuing to control based on the last valid value. Sometimes there's a status word, like on a Wireless gateway to indicate a wireless node is...

1. Observation On average, I drive about 100 miles (160km) daily to various plants that are not construction sites - they're operating plants. I need to wipe the transparent lens on the front of the car radio at least twice a week to clear it of dust buildup. The vehicle is 2 years old...

I'm an industrial guy so I think in terms of protected wiring: trays, conduit, panels, ducts, etc; and long wiring runs between sensors: hundreds of meters. And you're talking breadboarding. If your sensors are all local and fit on a breadboard then have at it. Industrial signal...

RS-485 multidrop networks are daisy chains, as shown in the graphics in the links below. This is a 4 wire RS-485 multidrop: https://s9.postimg.org/j3a8i55en/rs385_4w_2w.jpg This is a 2 wire RS-485 multidrop: https://s9.postimg.org/kv37d36rz/2_wire_multi-drop_with_terminating_resistors.jpg

I like the PIE's. Our company has had a half a dozen 334's (4-20mA calibrator/sources) for at least 7-8 years now. The 820E and an 830 are maybe 3-4 years old. I have used the 4-20mA, volt, thermocouple and RTD, both source and read functions, and all work as expected. I like the...

>"send it to the cloud or it can store it in a local data server." This is really critical part - the database software that creates a database, handles the data storage and provides tools for data reporting and analysis. HMI/SCADA software is typically used because HMI and SCADA software...

Your objective is not clearly stated as to who or what needs the circuit breaker data. Does the PLC need the data from the circuit breaker(s)? Or is the circuit breaker data needed elsewhere? A PLC is hardware box that works in real time. It generally does not store large amounts of data...

I have no idea what a CB is. But if you have devices that are Modbus slaves without wired connections, a wireless network has to be a primary consideration. Your secondary consideration is what software manages the data collection, storage and at some point, analysis. This is typically HMI...

> Is there really a difference between 2-wire and loop-powered devices? Answer: No. "Loop powered" is a passive 2 wire device. > In other words, can a 2-wire device NOT be loop-powered or a loop-powered device not be 2-wire? Answer: One has to specify the 'signal', not the 'device'. A...

The app in this thread is for Modbus ASCII which uses LRC, not CRC. SimplyModbus has an explanation for calculating an LRC value here: http://www.simplymodbus.ca/ASCII.htm Summarized: To calculate the LRC: 1. Add up all the data bytes in the message (before converting to ASCII and...

Apparently your Modbus app is transmitting the colon character for the start of the message, a calculated LRC value and the CR LF characters for end-of-message because you got a response from the slave. Your message :07031000 is requesting slave 07 to read holding registers (Function code...

With regards to current loops (instrumentation 4-20mA current loops, for example) - an active output signal regulates the current level, excites the current loop, and excites other loop powered devices wired in the loop (e.g. a loop powered display). For example, the analog output from a...

Thank you for posting the flowmeter model. It helps to know what you're talking about. Snippets from the Elster Instromet Model 2000 manual at https://docuthek.kromschroeder.com/documents/download.php?lang=de&doc=12356 1.0 Introduction, Section 1 A feature of the Model 2000 is that it...

If there is an existing serial Modbus network, you should confirm that adding one or more devices to it will not slow down the bus's throughput to the point where overall performance is affected. The Modbus master polls each device in turn, gets a response and moves on to the next device...

Why stop at three outputs? This little baby gives you four 4-20mA outputs: https://www.laurels.com/qls.php For a meager two outputs, there's several models here: https://api-usa.com/signalconditioners-signal-splitters.php