Search results

1) Wireless HART gateways talk Modbus. In wireless HART, HART is protocol used over the airwaves between the field transmitter and the 'gateway', the box that field data comes into at the control room end. Wireless HART gateways routinely use Modbus/TCP (ethernet) slave registers for providing...

The leadwire compensation is done by the device that the RTD connects to, not by the RTD or its interconnecting wires. 3 wire RTD connections are the most common because there is lead wire compensation with the assumption that the lead wire is the same gauge and length for all three legs -...

I just noticed, it's a temperature transmitter. Many temperature transmitters are not isolated input to output. Is your transmitter isolated? Does it have I/S approval? Is there a control drawing in the manual for I/S installation? If you have a grounded thermocouple with a...

The loop's large value for wire resistance, >2000 ohms, caught my eye. And that value apparently does not include the analog input's dropping resistor, typically 250 ohms. Typically, 2 wire loop powered field instruments can drive a total of about 1400 ohms of loop resistance at 42 volts...

I saw a combination of a metallic scintered filter directly connected to the low side port (called an exhaust muffler, used to muffle exhaust from ports on solenoid valves, comes on a 1/4" NPT nipple), along with the foam that covers newscasters' microphones on draft range DP's on a large...

Given the info thus far, A 0.1 second drop out is one, single update value. Signal drop out infers an intermittent open circuit in the loop. Ordinarily I'd go after a loose screw on a terminal block, particularly with 3 junction boxes. But you say you substituted cable from another...

Yes, as long as - there's not a ground loop that fritzes things up. A loop isolator might be needed. - you sort how the analog output gets powered

One thing that comes to mind is a spur or stub connection to the problematic slave that could cause a reflection whose 'noise' could alter a bit or two that the CRC picks up. But that would only be a possibility if Modscan connects differently than the SCADA connects. If both connect the...

1) Thermocouple or RTD wired with an IS barrier to an electronic high limit controller in the safe area. Too many vendors to list. 2) temperature switch United Electric Series 120 EXP rated temperature switch http://www.lesman.com/unleashd/catalog/switches/ue120.pdf Temperature switch...

According the E&H manual, the 10W flowmeter has an active (powered) 4-20 mA output that can drive 700 ohms. There's a reminder that if you need HART communications, that a miniumum of 250 ohms of loop resistance is required. That shouldn't be a problem. The way one converts from a current...

1) When the signal 'drops' or you lose it for a period of time, a) does the signal go to 4mA or 0 mA? b) how long is a short period of time? 0.1 second? 1 second? 10 seconds? 10 minutes? c) How often is this happening? 2) "Fluctuate" means to oscillate up and down a)...

First you have to identify the source of the error to know what to do to avoid it. You can substitute a different pressure transmitter and see if the same errors occur. If errors persist, then it is not a 'transmitter' issue, it could be either a process or an electrical issue. Given...

Have you contacted the instrument's manufacturer and asked for an accuracy spec and a source for referencing that value (like a spec sheet)? FYI, when an accuracy spec is stated it is assumed to be at some "reference conditions", like room temperature (60°F?), atmospheric pressure and within...

For those looking for an alternative to the TriLoop and its issues, Moore Industries has the HIM HART Loop break-out box that is functionally similar to a Tri-Loop. The HIM has three 4-20mA outputs, 2 alarm relays, and Modbus RTU slave registers. It comes with a Windows program for setup...

What is referred to as a 'span limit' of 0.06 - 6 bar probably reflects the span "turndown" of a smart gauge pressure transmitter, with the narrowest/smallest span being 0.06 bar (0 to 0.06 or 0.50 to 0.56 bar) and the widest span being 6.0 bar. 0.06/6.0 is a 100:1 turndown. Most gauge...

One advantage of floating point is that the very low analog values (4th, 5th 6th digits to the right of the decimal point) flicker noticeably because industrial analog values never hold that steady down in that region. That flicker can be handy when using Modbus over wireless because of the...

On page 8, the manual states: "The transmitter has been calibrated by the manufacturer in accordance with the ordering information. The values for the lower and upper range values can be seen on the type plate. The following is basically valid; in the line "Einst./Adj", the first value...

Tony Kuphaldt's Lessons in Industrial Instrumentation, an on-line work of significant quality and depth. It's huge download, 90Mb or so. http://www.openbookproject.net/books/socratic/sinst/ Omit any space(s)that the forum inserts into the URL.

Answer: None. This model pressure transmitter does not use a digital protocol. Google's first hit for ABB AMD 230 is at www05.abb.com/global/scot/...nsf/.../42_15_537_en_06_02_03.pdf That document states: The AMD 210/AMD 230 Transmitter consists of the D037 (2) or D057 (1) Measuring...

That maximum flow rate (gpm, lpm, whatever units) is missing from your list of orifice details. The 'design' DP of 1250mm wc is the DP for a 'design' 'maximum' flow rate for some set of 'design' conditions: medium, temperature, pressure, etc. Whatever that max flow rate is, (the max flow...