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Your link is for an Output board that might (maybe) could drive a valve actuator, depending on the actual actuator. It also has various motor drive outputs. Pressure needs to be measured with a pressure transducer/transmitter whose electrical output signal will be read by your Arduino as an...

Temperature values frequently have a low scale or high scale burn-out or failsafe value setting, and it's common to see that when a sensor is disconnected because disconnection is a fault/bur-out/failsafe condition. But burn-out is full scale up value or full scale down value; it is not a 32...

Data types/formats There are four IEEE784 formats for 32bit floating point (real) values (a value with some number of digits to the right of the decimal point). A 32 bit word consists of four 8 bit bytes. A Modbus register, frequently called a 'word' in Modbus vernacular, is 16 bits. If one...

A command is a Function Code sent by the Master/Client. I would interpret a limitation of "10 commands per second" as meaning that the master/client can not execute any given Function code command more often than every 100mS. Executing another Function Code command 100mS after another would...

At least one vendor of piezo-resistive technology smart pressure transmitters 'characterizes' each sensor element over the range of spec'd operating temperature while applying various reference pressures and recording the resulting pressures, which is the unique characterization data set for...

For a potential future purchase of hundreds I'd think you'd run own evaluation installing a one of each side by side in the same tank and determine the installation, setup, operational and performance differences for yourself, and do a test on one a tank considered "problematic". If you...

Are you using the term 'wet leg' for a remote seal DP transmitter? Probably not, one doesn't 'pump up' seal capillaries without some dedicated effort (vacuum evacuation and backfill). It isn't clear to me how you have a wet leg on the level's process bottom side that does not pollute itself...

The STD924 has a factory range of 0-1,000mbar (LRL = 0.0mbar, URL = 1,000mbar) with a 100:1 turndown for a potential minimum span of 10mbar, or 0-10mbar (LRV = 0.0mbar, URV = 10mbar). Configuring the range depends on the exact model. Most ST3000 series had Honeywell's embedded DE protocol...

What material is in the vertical impulse lines between the orifice plate and the transmitter?

Good job, Curt. I second all your suggestions. They go right to the heart of the problems that show up here time and time again.

Here's what the 3051 manual says about saturation level: 2.9.1 Configuring alarm and saturation levels In normal operation, the transmitter will drive the output in response to pressure from the lower to upper saturation points. If the pressure goes outside the sensor limits, or if the...

The Sepam manual gives part numbers for digital connecting cables (RJ45). I have no idea whether those cables are conventional Ethernet cables or not. The analog output signal connection from the options board to the PLC analog input can be any shielded twisted pair cable. Whatever the...

If you're talking star topology, you must be talking multidrop RS-485. Multidrop over RS-485 is supposed to have very short "stub" wiring at a node junction where the 485 signal comes in, Tees to the device, and then goes out again to the next device down the line. The stub Tee...

No, you do not use any RS-485 communication module for a 4-20mA output signal. 4-20mA is an analog signal which uses the MSA 141 analog output module Your statement, "to use the MS 141 communication module and the Modbus RS 485 2 wires interface and configure the relay by entering the...

"continuous transmission mode" is NOT Modbus. RS-485 is probably some proprietary protocol. You should start with configuring the Comm port for "2 wire Modbus" (I'm presuming "2 wire" means 2 wire half duplex RS-485). Make sure that the serial communication parameters are identical on...

You beat me to it, Ron. Good for you. I'd been thinking about cranking out a Modbus book, too. One thought that crossed my mind was reverse ordering chapters where I'd start with troubleshooting problem chapter first, then work forwards into what Modbus is and how it works, primarily...

Temperature control can be "slow" because of the process's ability to pump heat energy into the system is limited. Limited steam flow, limited burner size, limited heating element size, whatever. Changing the tuning will not "speed up" slow temperature control which due to insufficient...

A(n IEEE 764) 32 bit floating point value has - a sign bit - 8 bits representing an exponent - 23 bits representing the mantissa A first step in dealing with 32 bit floating point is to assemble two 16 bit Modbus words in the proper high/low byte and word order (concatenation), but that...

An input configured for J type, but wired with a K type thermocouple will produce erroneous high readings, where the higher the temperature, the larger the error. Is the input really configured for a Type K?

Thanks for providing your detailed troubleshooting process. That helps others seeking help when they search for solenoid problems. An open neutral, huh? It isn't the first time . . .