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Shield ground? Your shield should be grounded at one end only (unless it's Profibus and your site grounding meets Siemens' expectation of equipotentiality, see note below), precisely to avoid carrying ground loop currents, because as we all know, potential (voltage) differences are what drives...

Several possibilties that I have seen over the years for low reading RTD’s: Presumably the RTDs are in thermowells. If the shell and tubes were replaced and the thermowells also, then the thermowell placement might be different than the previous installation, resulting in temperature sensing...

There's obviously a problem with ultrasonic unit. The display probably shows some kind error code. It could be lack-of-echo caused by any number of issues, any of which could be component failure at the transducer end or in the electronics module end. The ultrasonic level market has gone...

Assuming that the input is configured properly and wired properly, then one has to consider the difficulty in driving the 4-20mA loop current through two devices in series, particularly with 4 wire devices that are AC powered, is that the each device's input signal is eventually referenced to a...

Current signals can extend much further than voltage signals, allowing robust signal wire lengths of up to 1,000 meters. I've seen current signals, both 4-20ma and serial current loop drive far longer than 1,000 meters, in one case 5km. The wire resistance is a factor, and in one case the...

Restating the fact that you want an X-Y plot does not advance your situation. It shows a remarkable lack of incentive to solve your problem. Have you googled X-Y plot, or X/Y plot and the application in which you need it? Have you sought assistance in the help files using a term other than X...

See what the Rosemount manual says on page 6-5: https://www.emerson.com/documents/automation/Manual-Rosemount-1152-Alphaline-Nuclear-Pressure-Transmitter-en-89476.pdf

You buy a USB/RS-485 adapter. I prefer those with an FTDI chipset, because FTDI registers their products with Microsoft which makes installation on the PC easy, I've never had to load a driver because Windows has the driver for FTDI. A USB/RS-485 adapter installs on a virtual COM port. You...

If you're developing a product, there are USB standards, see the USB.org site. https://www.usb.org/documents

Does Modbus do what it is supposed to if you disable the fault detection/Comm problem reporting routine? Or do you get long-term drop-outs, like a drop-out in excess of one minute? Can the PLC execute a 2nd poll to the faulty VFD within the 4 second alarm delay period?

Something doesn't make "Modbus" sense here. Apparently the inverter, a Modbus RTU Master, is communicating to a meter, a Modbus RTU slave, over RS-485. Correct? The specification/rule for Modbus RTU is that only one Master is allowed on the network in order to avoid collisions between data...

According to a statement in Serial Port Complete (pg 2 paper, 2nd Ed, 2007, by Jan Axelson), the "maximum distance between a USB device and its host is 16 ft, or 98 ft with five hubs." There are commercial cables available for those lengths. Why not use a commercial cable and save yourself the...

That was excellent troubleshooting on your part. Thank you for the feedback. It might well help others searching hints on troubleshooting a "lost communications" issue.

The buzzer on the TV quiz game started squawking EHHHHHHHHHH at your statement "I assume the inverter is the Modbus Master". That's a false assumption. Field devices are generally a Modbus slave/server. The proprietary software that you have has Modbus Master/client functionality. And I'm...

It could be a hardware/wiring issue. Presumably this is an RS-485 daisy chain wired network. Are you sure that when you "pull the modbus connector to the device" that you are not disconnecting downstream daisy-chained devices at the same time? If the device you disconnect is the last...

A power cycle is power-off, then power-on. When power is lost any instrument with a 4-20mA current output will output zero current and the receiver device might be programmed to flag/alarm that loss-of-signal externally as an fault state. Receivers typically alarm internally on loss of...

1. Slave ID Is there some other document that specifies how the Modbus slave ID is configured, dealing with the FAA dEA? I'm totally lost on your formula that has a 16 multiplier factor. A slave is silent and does not reply unless it recognizes its own slave address in an incoming message...

Time-out means the master attempted to send a message, but failed to get a response. That's usually at basic level, wiring and configuration 1. COM port # You have a USB/RS-485 that installs on a Windows 'virtual' COM port. The COM port needs a number, COM1, COM2, COM5 whatever. In Windows...

There's no flow through an impulse tube, it is dead-headed. Transfer of heat from ambient air will heat impulse tubing and the valve manifold and vaporize the cryogenic liquid. On initial installation, keep the block valves closed for a period of time to allow vaporization to occur and...

Check out pages 236-237 of Emerson's Engineer's Guide to DP Flow Measurement (2020) You'll have to register to download the guide from the Emerson site https://tinyurl.com/yxc4srer Cryogenic measurement relies on allowing the cold liquid to vaporize in the impulse tubing and/or valve manifold...