Archive for the ‘Manufacturing’ Category

Measuring Flow

Saturday, January 19th, 2008

We need to measure the flow of a liquid through a pipe at work. This seems easy enough on the surface. I’m thinking…just “click” off the liquid in some measurement as it goes by…right? Well, it could be…maybe. In reality, it turns out that it may not be all that simplistic. There are other things to consider. What kind of meter should you use? There are many. What exactly are you trying to measure? What’s the density or viscosity of the liquid? Are these variable during the process? Are you actually trying to ‘regulate’ flow or ‘meter’ flow or both?

During the consideration of this task of measuring the flow of a liquid, we would need to define ‘flow’. The straight-forward definition is… the flow of material past a given location. When we dig into it further and look at actual formulas for measuring flow, it starts getting more complex.

For instance, look at this formula for ‘Flow Rate’ (FRV). This is a volume per unit time or ‘volumetric’…

FRV = V x A, where A equals the cross-sectional area of the inlet pipe and V is the average velocity of the liquid being measured. Now consider this formula in practice. We have liquid flowing through a pipe that has 2 square meters of cross-sectional area, traveling at an average velocity of 2 meters per second. So, I have a flow rate of 4 cubic meters per second.

Next, look at this formula for ‘Flow Rate’ (FRM). But this time, we will deal with ‘mass per unit time’ or a ‘mass metric’…

FRM = FD x FRV, where FD is the fluid density and FRV is our volumetric product from the first example. So, if 4 cubic meters per second of fluid is flowing through a pipe, with a density of 2 kilograms per cubic meter, your FRM is 8 kilograms per second.

Do you want to measure flow in terms of a ‘mass’ or ‘volume’? It depends on your application. In some instances the process may have a limit on the ‘volume per unit time’ measurement it can accept. Some examples might be…filling a tank, painting widgets, etc. Other processes may have a limit on the ‘mass per unit time’ it can accept…like mixing chemicals or measuring chemicals for sale.

You can see that a person can purchase a meter that measures flow in terms of volume or mass. I found that you can even buy meters that ‘infer’ volume and mass using a similar formula to ~ ‘1/2 FD x V x V’. These meters are commonly referred to as ‘head flow meters’. But, further reading indicates that this ‘inference’ approach is problematic and can introduce errors when calculating ‘mass’ flow.

Careful consideration of what you really intend to measure about ‘flow’ should lead you in the right direction when purchasing a meter. Do you want to measure velocity, mass, volume or inferential values of each?

Wade Stankich
Information Technology Manager

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Bridging the Gap Between Maintenance and I.T.

Saturday, January 5th, 2008

Over the years, it seems that past traditional roles of the maintenance department and the information technology department of a manufacturing company are (or have been) changing. The lines are getting blurred. Those guys in the ’shop’ with the wrenches need to be just as versed in techno-jargon as ‘those geeks’ in the computer room. The I.T. guys also need to understand plant operations and maintenance concepts and the language that goes along with it, too. Why?…plant automation.

Most backplanes you see on the plant floor have a multitude of different modules plugged into them besides just the PLC. Today, usually a person will find an ethernet module plugged into them. For the I.T. department this is another network device on their network. Many times an electrical engineer deploying a new machine with an ethernet module gives no consideration to an IP address that fits with the companies current scheme. They may not give consideration to broadcasting issues that can potentially bring a network to it’s knees.

Conversely, a typical I.T. department doesn’t give enough attention to what basically amounts to another I.T. department within maintenance. Most of the machines maintenance deals with have processors and can be networked today. The engineers in maintenance are skilled at programming ladder logic, and once that task is complete…it simply goes out. I.T. should be working with this department to help them successfully roll out there machinery and take on the more global considerations of the company’s network.

This cooperation of two departments, that are so different on the surface, is sometimes easier said than done. It can be a huge cultural shift for some companies. This cultural divide usually is established from the beginning because of typical organizational structures and the resulting presumptions. What I mean is, that typically the maintenance department falls under Operations and the I.T. department falls under Finance. Foundationally, the wall of separation is “…I.T. is administrative, and Maintenance is production.” This may have worked 30 years ago, but it is no longer a valid structure that serves it’s company well, or to the fullest potential.

The Maintenance department and the I.T. department need to be solidly joined at some level. Neither, falling exclusively under Operations or Finance, but working somewhere in the middle for the global good of the company. It starts with communication. Project managers of both departments meeting once a week to review projects would be a good start. At some point along the way each will realize they both share the same copper wires.

Wade Stankich
Information Technology Manager
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When Web-Based Isn’t The Way To Go…

Tuesday, December 25th, 2007

As a former developer that has developed windows applications, as well as n-tier web-based solutions of the LAMP variety…whenever a new application needs to be developed, I naturally gravitate towards the n-tier web-based scenario for a multitude of reasons. Nine times out of ten, we come up with a good web-based solution, but not this time. Here’s the scenario…I need to scan bar codes on metal drums filled with 25-50 gallons of liquid paint, in a storage facility that holds over seven hundred 50 gallon drums, in plant with hundreds of thousands of pounds of aluminum extrusions everywhere…and be wireless!

We started out with a class 1 div2 Symbol MC9090 scanner with Windows Mobile 5. We developed a web-based application that was written in PHP and ran in our middle tier. So far no problems. After using this scanner for a while, we noticed intermittent problems with connection. OK…no problem, we anticipated this, because the environment is the absolute worse for wireless. So, we amplified the signals and positioned the antennas in another arrangement to optimize coverage. We also trained the production personnel to do basic functions, like rebooting the scanner, if needed. This actually happened once or twice a day, so we were not happy with it.

Occasionally, for reasons we have not yet determined, the scanner would completely reset itself. OK…fine we’ll buy a second scanner just like it for backup, in case this occurred during the middle of the night. Here’ where the really annoying part comes in…unless you purchase all the scanners you’ll ever need at one time, no matter if you order the same model two months later, Microsoft is always tinkering with the OS. So, you can purchase 10 scanners over the course of a year, and potentially have 7 different backup and recovery strategies!

By this time, I’m looking for other solutions to simplify things. I was at an AutoZone store and while I was at the counter, I saw an MC9090 sitting in front of me. I thought surely they can’t have hundreds of these things and be experiencing the same problems…that would be a nightmare! So I picked it up and saw that they were running an SSH client on it. HMMM….

I went back to work and told my team what I observed and asked them what they thought about it and what would be the possible advantages to running an SSH client instead of a web application on the scanners. The result from that discussion was that the SSH client is much more tolerant and transparent when it came to signal lose…Bingo! Also, everything about the user’s perception of the interface was much more simple.

Additionally, because each scanner seemed to be a bit different than the next, in the original scenario we had to setup each one a little different in order to get the web application running again. Depending on what we wanted to do, we woud also have to run Opera, IE, or MiniMo because of coding differences that effected javascript. This was a huge headache. Now, all we have to do is reload the OS and the SSH client…done!

As always, I welcome any suggestions or ideas…otherwise, maybe this post can save someone else some time.

Wade Stankich
Information Technology Manager

Posted in Management, Manufacturing | No Comments »