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It depends. If the address is a Holding register address then it is in the (4)xxxxx Holding Register memory area. If the address is a Input register address then it is in the (3)xxxxx Input Register memory area. The leading numerals (3) or (4) are not part of the Modbus message, but are...

A friend inherited his Dad's process instrument field calibration business and his Dad's notebook. The notebook lists locations of "Cold Junction" reference points for various plants, building or units, for instance, NW corner of the rolling mill, 6 feet west, 3 feet south, 4 feet deep, 54...

What your DCS guy is asking for a very logical - the DCS is the Modbus (or OPC client) master which means the field device, the SmartAir Lite needs to be a Modbus slave. Modbus slave's each have a unique slave node address (1 through 247). The baud rate and parity need to match the DCS serial...

See the Doric 400 user's manual here: http://www.advindsys.com/Manuals.htm The 400 appears to use sensor specific hardware, as shown on page 2-5, an LSI chip and programming module. Every industrial device I ever seen has a model with configuration and options codes. How Doric...

The Doric series 400 manual at this URL: https://intertechnology.com/Doric/pdfs/400_Series.pdf shows each model has an 'order code', a 3-xx code, that defines that unit's functionality. For instance, the K type T/C indicator is 3-01. The 4-20mA input indicator is 3-61. Is your device...

FYI ASCO solenoid valves have I/S models http://www.lesman.com/acatalog/ASCO_Valve_WBIS_Intrinsically-Safe_Solenoid_Valves.html or EX models http://www.lesman.com/acatalog/ASCO_8210_Explosion-Proof_Normally_Closed.html

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...