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To turn it on or off via the web, there is a COTS box designed precisely for that, the web relay. http://www.controlbyweb.com/webrelay/ I'll have to ponder a temp controller with a web interface

The closest single module that I can think of is Acromag's line of Modbus TCP (ethernet) slave modules with multiple 4 - 20 mA analog input(s). The Acromag 961EN includes a web server with web pages for configuration and testing. One of its web pages shows the scaled analog value(s), but the...

> 2. Positive to Ground > 3. Negative to Ground. 1) "Ground" means? - power supply negative? - a bonded earth ground in the panel? - the steel pipe driven into the ground that the transmitter is mounted on? - the receiver (analog input) negative? - something else? 2) Is either...

> Now if I reverse the connections, shouldn't the transmitter read the same? Value should remain the same, but the algebraic sign should change from plus to minus or minus to plus. Some brands require factory characterization for reverse connection to meet an accuracy spec. I don't know...

I just did a project with 2 video cards in a PC that drive three 42" TV Hi-def screens, but I used VGA because the distances from the PC that grabbed the process data and the screens was 200 feet to 600 feet in different directions. DVI has about a 200 foot limitation. These were read-only...

It appears that the documentation available to you lacks the basics about the serial port and its default setup. Does whatever documentation you have access to provide the Modbus register map? If not, of what value is the port configuration? I ask because compressor mfg's seem to...

Those kinds of offsets might be related to uncompensated lead wire resistance in 2 wire RTD connections. Although I have to admit I'm not sure how a relatively modern controller could not do leadwire compensation that it's designed for. Unless the 3rd wire isn't connected to the terminal it's...

1) what range is 100%? 1", 10" 100"? 10mm? 100mm? 1m? 10m? 2) Are you using remote seals? Or impulse tubing ? 3) Has it ever read properly, or is this a new installation issue?

>Every sensor is very far from each other Very far means 10m, 100m, 1000m or 10000m? How many buildings? How far apart? The instruments are all Modbus RTU. Copper wire daisy chain them over RS-485. If the buildings are networked on an ethernet LAN, then use a serial-to-ethernet...

The one technology you haven't mentioned: semaphore. Seriously, what kind of answer can you expect throwing all those buzz word technologies on the table with absolutely no context? Google will locate vendor or trade journal articles on this topic (with its usual drawbacks). As a forum...

The nitrogen blanket pressure does not figure into the calculation, the DP transmitter sees that pressure on both high and low side ports and cancels it (high side minus low side). As an example: With the transmitter flange mounted at the bottom (transmitter high side port) and 12' low...

The LRV and URV have to be calculated. To clarify, - the remote seal flange with capillary is mounted at the bottom (or close to the bottom) of the tank (true?) - a 12ft capillary connects to the high side of the transmitter which is 12.00 ft in elevation below the flange? (this...

Negative values are common when capillary remote seals are used. You have not mentioned capillary remote seals. Does this particular transmitter have one or two capillary remote seals? If so, - the elevation of the transmitter with respect to the lower seal position - the elevation of...

Is the medium in the tank water? What is the medium in the tank? Its specific gravity is? Which head pressure units are you using? inches water column? Are you reading level at some receiver device, like an indicator/controller/DCS/PLC? If so, which level units are you using...

Look for a product called something like - Modbus serial-ethernet gateway - Modbus serial server - serial to ethernet device server from vendors like - HMS Anybus - Digi - Lantronix or a dozen others Be sure to pay extra for the Modbus model/version.

> You could put a Modbus serial-ethernet gateway at the PA controller end. This > way the SCADA system and your PC could access the device via ethernet. This assumes - that the PC can run or is running Modbus master software. An alternative is having the PC be a slave, where the SCADA...

Please, give this a try and report back to us on the details of how it works. Remember that Modbus RTU uses 8 data bits and that Modbus ASCII uses 7 data bits, so be sure to change the data word format on the serial line depending on whether it's an ASCII or RTU transaction and hold that...

For industrial tank and hopper weighing (agitated, too), I'll say that there is a best - the Sartorius (formerly GWT) load cells. It is driftless, due to its technology that etches the strain gauge rather than bonding with stability over time that is 2nd to none. There's no tweaking to keep it...

There's numerous instrumentation/control text books, like Process Control Instrumentation Technology by Curtis D. Johnson, that can be had for pennies on the dollar from used book sites. Note that this title in about its 8th or 9th edition. Flow technologies cover about 6 pages of 700, but...

The model number is PAC-E100, (the manufacturer is PNC), the model number is not PNC-E100. http://afb.com.tr/document/pnc.pdf Attention to detail is CRITICAL for success in digital communication. The last field in the model number, Cx, defines the communication option, if installed...