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No clue what a Hagan F is and 1st 10 hits on Google don't say. Presuming it is a pneumatic level transmitter that you're getting rid of, you need to power the 3051 loop with a 24Vdc power supply and wire the 3051 4-20mA output to the input of the I/P. The power supply (+) goes to the 3051...

I'm not sure what you mean by piggyback. Do you mean two loads in series: an I/P for the pressure chart AND an analog input load? It should work. Bellofram's 3-27psi I/P has a nominal impedance of 220 ohms. Others are probably in the same range. Typical analog inputs are 250 ohms. A...

Wow, different slaves at different serial settings work on the same RS-485 network/bus. I can only speak experience and my experience is that slaves are fussy and refuse to communicate when the serial settings don't match those used by the master. I have never tested a slave for...

Lots of numbers in your post, but some critical ones (and engineering units) are missing. I doubt you "dropped only 200 mil(li) amps". More likely your transmitter is a voltage transmitter and it lost 200mV over the wiring. Current loops (milliamps) are 4-20mA and the nature of a...

You need a separate serial port for each unique set of serial settings. In your case, 3 ports, unless you can change the parity on ID 125 to 'even' and run ID 125 with the ID 32, 33, and 34 where the baud rate and parity are common to all four IDs. Then you'd need only two serial ports.

Presumably each Modbus TCP card has its own setting for timeout? I'd separate known slow responders from those that are quick responders. For instance, the pH meter, run by an 8 bit micro that struggles to reply over RTU in less than 2 seconds at 1200 baud, which then connects through a...

> it's really important to know the right polarity of RS-485 communication Yes, because it doesn't work when it's backwards. > before you implement it. Not necessarily, connecting it backwards does not damage the drivers, it just won't work. > but not with RJ45 connector. Google...

We humans need conventions to help us deal with binary. Hexadecimal is an example of a short hand representation of a binary string in a shorter form. The leading numeral (4) for holding register identification is a convention used by humans to help identify the value as being in a holding...

I don't know, but the way most of us deal with it is to hook 'em up and see if it works. If it doesn't, swap the wires. Mr B&B Electronics wrote a white paper on the Polarity of RS-485 driver lines including the history of naming or misnaming the lines. It's a 2 pager, and the last...

It sounds like you are seeing step changes in the data. An example with numerical values would help, along with a description of the process variable would help diagnose the issue. 1) Wrong FP format There are two widely used floating point (FP) word/byte formats (big/little endian, byte...

The most significant bit for both IEEE754 floating point and signed integer is the sign bit; a logic 1 is negative, a logic 0 is positive. The IEEE 754 32 bit floating point format amounts to two 16 bit Modbus 'words'. The sign uses one bit, the exponent uses 8 bits, the mantissa uses 23...

>Our transmitter have option T1. But it might not functioning due to no case grounding for transmitter. That's right. Quote from the manual "The transient protection terminal block does not provide transient protection unless the transmitter case is properly grounded. Use the guidelines...

The 2051 manual says the 4-20mA fail-safe alarm level is equal to or less than 3.75mA The 2.5mA you report is less than 3.75mA indicating catastrophic failure of the electronics, which is what you found. Reason? Could be the absence of the surge or transient protection (option T1)...

I have no clue what might be wrong with your unnamed, unidentified transit time flow meter. But, if doppler sensors 'do better' than transit time on chilled water, you have serious problems with the chilled water line. Doppler requires bubbles or suspended solids to reflect energy...

Direct exposure will cause stainless steel to fail.

Yes, the acid will destroy the gauge. You need a diaphragm seal, which separates the gauge internals from the process medium. Installing a seal requires a vacuum pump to pull a vacuum before filling the gauge/seal volume with fill fluid. One typically buys a gauge and seal assembly...

> (Can) the HART FSK output signal from DAC can be observed on the oscilloscope? When it's there, yes. But it's probably not unless you have a HART master polling the slave-ship. A standalone Hart-enabled AI chip does not broadcast HART data. HART is a master-slave protocol and the...

I don't know about the range of the transmitter or the control room range because those are specific to the application, but the HART PV of 60kPa is sort of in the ball park for an LRV. The PV 'zero' value for a DP with dual remote seals depends on the elevation differences between the tap...

The "Manual on the Use of Thermocouples in Temperature Measurement", ASTM Special Technical Publication 470A, dated 1974 states, "The commonly used thermocouple types are identified by letter designations originally assigned by the Instrument Society of America (ISA) and adopted as an American...

I assume, because it wasn't stated, that the level is supposedly constant and the 10-15% change is a measurement artifact, and that the level change is not due to someone on the night shift taking some process water to make a pot of tea. It is normally recommended to use dual remote capillary...