A Field Guide for Engineers
A Field Guide for Engineers will provide instructional content and inspiration to novice and veteran engineers alike. Covering design, commissioning, troubleshooting, and operations on HVAC and electrical systems and controls, this blog will be informal and fun, and very rich in content.
Learning By Doing
I realized as I started to follow up on my previous post about selecting a cable for use in a temporary data logger field deployment with the DC power supply panel that before I could talk about why I might have selected a certain cable, I probably need to talk about about the general construction characteristics of the cables I was looking at.My own knowledge about building wiring practices start ...... Read More
Comments (0)Using the DC Power Supply Panel in the Field - Picking Cable
To be able to use your DC power supply panel out in the field, at some point, you are going to have to buy some cable or wire to hook up your sensors. Using current loops gives you some flexibility in terms of the exact configuration of the cable you use. Here is a picture of some of the cable types I have used and have sitting around in my shop. From left to right: The light blue cable is a ra ...... Read More
Comments (0)Operating Data and Commissioning; The Two Go Hand in Hand
Analyzing building data is key to the commissioning process, including the use of trend data from the building energy management system and/or independent data loggers and the ongoing monitoring and analysis of utility data. As a result, the commissioning conference typically includes a number of sessions that are focused on various aspects of building data analysis. This year was no excep ...... Read More
Comments (0)Pump and Motor Interactions - The Video
The picture above is a motor performance curve for a 5 hp motor from Emerson’s U.S. Motors product line which you can obtain via their free MotorBoss website. Among other things, it shows how motor speed varies with the applied load. For those who want to see a better resolution version of the curves, I have them posted in the photo album on my CSE Magazine Google Account. Some ...... Read More
Comments (0)The 17th National Conference on Building Commissioning
Hello from Seattle where I have been attending the 17th National Conference on Building Commissioning along with about 350 other commissioning providers, researchers, program managers, building owners, and other folks with an interest in how to improve our building stock. Tuesday found Ryan Stroupe, Dave Mosier, Erin Rowe and I bussily presenting a workshop called Analog Lessons for a Digital Wo ...... Read More
Comments (0)4-20 ma Current Loops - Assembling the DC Power Supply Panel
Well, I finally got the drawings finished that I needed for this post and am ready to pick up where I left off in my last post in this series where I gave you the materials list for the DC Power Panel. In this post, I’ll provide the wiring information and a few assembly tips. The picture at the top of the post is of the assembled panel. As you can see, there is really not much to it. I ...... Read More
Comments (0)4-20 ma Current Loops - Answering a Few Questions
Wow, there must be a lot of people interested in current loops; that’s the most comments I’ve received in a short period of time after the post. I’m going to take a few minutes here to address a few questions. Meanwhile, I’m just about finished with the “how to assemble the panel post” and hope to have that up some time tomorrow if not so ...... Read More
Comments (0)4-20 Milli-amp Current Loops - Power Supply Panel Parts
Sorry for the break in the string; we just changed the software platform that drives the blog and its taken me some time to get everything set up and working with the new system. But hopefully, at this point, I am good to go and can pick up where I left off and keep moving forward. My previous posts before the transition to the new system had been exploring 4-20 milliamp current loops, ...... Read More
Comments (4)4-20 milliamp Current Loops; Interpreting Current Loop Information
This is the third in a string of posts on 4-20 milliamp current loops. So far, we’ve looked at why we use 4-20 milliamp current loops in the first place and how 4-20 milliamp current loops work. In this post, I’ll take a look at interpreting data from them and some of the calibration issues associated with them. Note that the calibration issues I discuss also apply to other signal te ...... Read More
Comments (0)4-20 milliamp Current Loops; What They Are and How They Work
In my last post, I started a string on 4-20milliamp current loops by looking at why we use them in thefirst place. In this post, I’ll take a look at how they work.The image below illustrates a basic 4-20 milliamp currentloop.There are a number of good resources out on the web that explainthe details of how a current loop works, including the Pumpsand Systems article I mentioned in a previou ...... Read More
Comments (2)4-20 milliamp Current Loops; Why Use Them?
A couple of weeks ago, while out in the field, someone asked me how one went about hooking a 4-20 ma current loop up to a data logger. Since I happen to have done just that recently for a project up near Seattle, including building up the power supply panels that are a big part of the solution (the picture below is the field deployed panel with logger monitoring a pneumatic signal to a control val ...... Read More
Comments (0)Touching Bases and Responding to Comments after a Busy Couple of Weeks
Well, I’ve had a busy couple of weeks and not done a very good job of posting; my apologies there. Hopefully, I can catch up a bit over the next few days. Work’s been busy, but I’ve also become a grandfather for the third time, which is pretty much fun. Here is a picture of our new arrival, Piper, with her big (and very excited and helpful) sister Arabe ...... Read More
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