Hi,
Does anyone know of a HART communications bridge device that couples bi-directional HART communications between two different 4-20 mA current loops? Meaning, no DC signal coupling between the two loops, transformer isolation with bidectional gain in a single packaged device would nice...
Thanks for your input on this topic. Yes, apart from the valve positioners users that take advantage of the embedded positioner features to achieve full valve seating, I wanted to learn if there was a standard or accepted pratice for those people that choose 3.85mA, or 3.80mA, or 3.75mA or...
Is there an industry standard or performance expectation for 2 wire 4-20mA output devices (actuators, positioners) for signal levels below 4mA? For example, many field transmitters incorporate special signal indications outside the 4-20mA interval for alarm levels or diagnostic indications. And...
Does anyone know whether any Hart hand held terminals can be used together with Ovation Hart I/O modules? I am thinking that AMS is the recommeded approach where Hart communications passes through the Ovation Hart I/O module but I do not know if loop connected Hart hand held terminals (ie...
I am thinking that stacking DP transmitters is ok. And I have done it for gases and liquids. And I agree for the most part with the 3 points but I would like to add that you have to watchout for density variation in the flow (liquid vs gas, and P & T variations), so you might want to stack...
I am pretty well acquainted with Hart but not at all acquainted with Ovation Hart I/O, except that I know that the Hart modem is multiplexed 8:1 on the Ovation Hart I/O module. And I am not seeking a comprehensive understanding of the Ovation system. I just want to know the basics of what the...
I am looking for some basic information from users of the Ovation Hart IO interface using Hart communications for data exchange between Ovation and instruments. Are there any particular requirements on the instrument; ie, is only Hart burst mode operation supported, what Hart commands are...
I am trying to find the subject Copper 10 RTD standard, any suggestions would be appreciated. The standard is listed in the HART Communications Foundation Document HCF_SPEC-160.4, Temperature Device Family Specification, code 101 . I did not have luck calling the Hart Foundation.
I seek recommendations for a small control system suppliers that can handle about 12 analog inputs, 12 analog outputs, 10 digital inputs and 10 digital outputs, with mixed analog and digital control, easily configurable control with one easily configurable operator console. Outdoor...
Is there some reference (code or standard) basis for the minimum separation distance between 1/2"NPT conduit entries on enclosures for Div 2 and/or explosion proof Div 1 locations?
Thansk in advance for any advice.
I don't think there is any difference. It used to be a little scary when the L stood for leadless in ceramic packages. As far as I am concerned all PLLL's have either J leads or gull wing.
Been there, done that. Result: no satisfaction or parts. I am working outside the box by posting my desperate message on the eng-tips site. The whole story has many trite and boring details but it is not complicated; ie, I need parts. Thanks for the reply but I still seek some good advice...
Start by gathering data on your existing parts, include costs; then prepare a database of parts. Better engineers tend to look through existing parts provided it is not cumbersome to do so, lazy engineers don't bother to look.
Unfortunately for me, I have been looking amongst the most obvious suppliers of HART equipment, including the two suppliers already mentioned but while there are several manufacturers of HART to 4-20mA (aka Tri-Loop contraptions) the best that I have been able to identify for the reverse, ie...