Thanks ControlNovice,
About the Z: yes, ZZS would be a limit switch in a SIS loop.
And hey, I dont know about it either..but it is what the new S5.1 calls for.
The bold is a good idea...I once thought I would make the "ears" a solid black on the circle circumscribed by the square. That would...
Hi All,
Since I posted this question I've read the latest ISA 5.1 on the subject and see that ISA's recommended approach seems to be by changing the nomenclature of the instrument tag and not the symbol itself. They add a "Z" after the first letter of the tag for an SIS item. FT-xxxx would...
To Mr Seagull's point- I was thinking about the actual instrument but since the controls are part of the SIS loop, I suppose either the system side or the instrument side would work.
The new ISA Standard does call out the diamond within square symbol for SIS but it isn't practical since the...
i'm working on a process plant where there will be a Safety Integrated System (SIS) designed for the process.
It occurred to me that it would be helpful to designate the instrument "bubbles" on the drawings if they are components of this system.
I'm curious to know from others if anyone has...
Thanks Ilan,
I probably need to elaborate.
I was more interested in the manhour estimate for the entire construction package, which would include all the I&C parts of meetings, scheduling, estimating, drawings,specs and support tasks that make up a design effort. We like to reflect back and take...
I did this once in my younger daughter's class. I think it was the 5th grade. I live in Tennessee and was telling them about the shuttle testing that I was a part of in middle TN at the Arnold Engineering Development Center.
At one point I was showing them the six degree of freedom motion...
I have worked most of my career for what is usually called A&E firms or Consultant Engineers. We make the construction drawings and develop instrument specifications for chemical process projects. Data sheets for instruments, schematics for connection to the PLC or DCS, instument location plans...
I'm just getting in to a security upgrade for a client who now uses microwave tx/rx technology to protect against perimeter breaches. I see that there is now another technique used similarly that senses for a disturbance in the light sent through a fiber optic cable that would be attached to a...
I have a very good book called the Control Valve Primer by Dr Hans Baumann that has a section on valve sizing with high viscosity flow and/or very low flows - even with a tapered plug as you describe- that may be helpful. It's available through ISA.
I agree also. Unless the site has an elaborate calibration lab, with NIST standard comparison equipment, dead weight air testers, etc., as well as well trained technicians more harm than good can come as a result of "calibration".I've seen it first hand.
I agree with Mr Seagull, Validation is...
I'm not sure I'm interpreting your question correctly but it sounds like you have a positioner waiting for a 4-20mA signal and you want to make it work as an On-Off valve?
If that is what you have, then a two wire cable is all you need together with the software set up to ask for 100% open and...
Thanks to JimCasey and controlnovice for your info. It all helps. I was also looking at the StoneL switches but it seemed that every spur with a switch would take a tremendous amount of room in the field cabinets.
Thank you Seagull for your response. There is a lot to consider when choosing a particular one - I'm learning. The actuator people I've talked to since I posted this thread seem to be generally pushing me to AS-i. Since that's what they have developed.
I'm going to a ABB Automation World...
The more I study the possiblities the more uncertain I become about what to use. We are doing an estimate for a chemical process plant where Foundation Fieldbus(FF) has been decided for use with Analog - Transmitters and Positioners.
The question is what to do with the on-off valves and...
Use a three port two way solenoid that will route air to the actuator when in the energized position and vent air from the actuator in the de-energized position.
