control panel building

[testsubject]

Depends on several factors. How much information is the customer giving you? In other words, if you are given a detailed schematic with specs for the equipment/devices to use and a control description, then your price would be based on the components you have to purchase and your labor to build and test. On the other hand, if a customer says "I have a machine and I want it to do this" then you have a whole different ball game. Also if you are going to have to program the PLC that adds another dimension to the project. My advice would be to start small if you can and move on to larger projects as you learn.

Something along this line of questioning, do you charge different rates for programming/panel layout?

 

[TConnolly]

I charge programming by the hour and use a combination of experience and IO count to determine the number of hours that will be required.

I charge per page for drawings.

In reality the hourly rates for the two activities is different.

 

[testsubject]

I charge programming by the hour and use a combination of experience and IO count to determine the number of hours that will be required.

I charge per page for drawings.

In reality the hourly rates for the two activities is different.

Thanks for the info.

When charging the programming rate, does that include estimated debugging time?

 

[TConnolly]

Debugging time? Whats that? I dont write bugs.


Seriously, debugging is under start up time. Its a complete W.A.G. based on experience. More often than not, I'm way off on startup time. There are too many unpredictibles, and many of those are beyond the programmers scope of control.

 

[testsubject]

Debugging time? Whats that? I dont write bugs.


Seriously, debugging is under start up time. Its a complete W.A.G. based on experience. More often than not, I'm way off on startup time. There are too many unpredictibles, and many of those are beyond the programmers scope of control.

Too true. I often have trouble anticipating what an operator will do to really mess things up...

 

[rta53]

We charge one rate for engineering and programming and a lesser rate for panel construction and testing.

Here is how we break out our costs:

Design
Engineering (Usually includes doing schematics and control description)
Programming


Layout and Build
Test

Oh, and may I add, our panels are built to control our water treatment systems that we design and build for customers. And we aren't cheap. :nodi:

 

[TConnolly]

Too many times its two months past the deadline and they finally get the electricity turned on and you finally get to start the software loading and system checkout and trying to get eveything to communicate with each other. And suddenly the entire two month overrun plus any installation mistakes you find is all your fault and the managers are po-ed. I hate startups because generally it means 14 hour days.

 

[rta53]

Too many times its two months past the deadline and they finally get the electricity turned on and you finally get to start the software loading and system checkout and trying to get eveything to communicate with each other. And suddenly the entire two month overrun plus any installation mistakes you find is all your fault and the managers are po-ed. I hate startups because generally it means 14 hour days.

And when you walk up to the panel you think to yourself, I don't even remember doing this project.

 

[testsubject]

And when you walk up to the panel you think to yourself, I don't even remember doing this project.

Project? What project? I didn't so this


Now pay me.

 

[Binaural]

What preferences do you all generally have for PLC location in the cabinet? I usually place the PLC at the very top. I realize that the top of the cabinet is usually warmer, but in most of the panels I do thats not really an issue. I place it at the top (with recommended clearances) for two reasons: First, the wires usually exit below the PLC rack, therefore there is little use for a duct above the PLC, conserving panel real estate by top mounting. The second reason is that at the top it is less likely that debirs will fall into the rack during field installation. There are of course times that I have mounted the PLC at the bottom or in the middle, depending upon the neeed, but my general preference is for top mounting. What say you all?

Depends on whether I am using AB or Siemens PLCs, and whether the panel is mounted directly onto the machine or freestanding nearby. With machine-mounted panels space is usually very tight, and often necessitates the use of 32 input/output cards. For Siemens cards this practically forces you to pull 20 cores upwards and 20 cores downwards, which means I have to run conduit all around the PLC. Fortunately Siemens also sells pre-wired terminal looms for these cards, which helps a lot

Otherwise, I put the PLC at eye level in the cabinet for easy access.

 

[Rube]

I've only built one panel for a machine, the rest of my panels are for conveyor systems, some easy--some very complex. Like my last panel/system/program. I always place the PLC in the top for real estate issues. I also place the inlet and outlet for air cooling in the top of the panel (remember that debate?) so the cooling air flows directly accross the PLC. Alaric, it sound as if you and I were to each build a for the same job they would be very similar. Wonder what that means?

 

[rsdoran]

I am in the process of creating a Panel Building Tips page. In my research on this subject I came across a few things that were not mentioned and could be real useful.

1. Greenlee makes Self Centering Hole Punches, this I did not realize.

2. There are Keyway punches but I use this Greenlee tool:

3. When drilling holes that are to be threaded you can use drill/tap combo bits. I do not know why I did not mention this.

The holemaking tools from Greenlee is here:
http://www.greenlee.com/cat_docs/Holemaking.pdf

 

[Rube]

Ron

I've seen those drill/tap combos but I've never used them. Are they pretty rugged? Problems with breakage? They are obviously speed sensitive.

 

[testsubject]

I am in the process of creating a Panel Building Tips page. In my research on this subject I came across a few things that were not mentioned and could be real useful.

1. Greenlee makes Self Centering Hole Punches, this I did not realize.

2. There are Keyway punches but I use this Greenlee tool:

3. When drilling holes that are to be threaded you can use drill/tap combo bits. I do not know why I did not mention this.

The holemaking tools from Greenlee is here:
http://www.greenlee.com/cat_docs/Holemaking.pdf
http://www.greenlee.com/cat_docs/Holemaking.pdfhttp://www.greenlee.com/cat_docs/Holemaking.pdf

I like using Greenlee hole punches because they make a clean hole but hate how difficult it can be to clear the slug. Does anyone have any tricks for making that easier? I have trouble geting the shop guys to buy into using Greenlee's because of this. They all say that is is much faster to use a hole saw and deburring tool.

BTW, I also agree with Rube. How durable are the drill/tap tools?

Bob

 

[Ed01]

This panel is not floor mounted but wall mounted on the skid.

As Alaric mentioned if water/moisture/condensation is an issue then that should be addressed. Maintenance electricians are constantly having to vacuum/dry panels because of engineering design flaws along these lines. The conduits filling with water is just as detrimental as the panel filling with water.

I do not have a bad back and I do not think it is part of the issue. When terminal strips are located at the bottom of the panel that means you have to, IN MOST CASES, work below eye level AND in closer proximity, physically, to the electrical equipment. Vertical mounted strips offer a better view without having to bend over or work around any devices. As a reference here are 2 examples that have been provided by Norm and Eric:
http://www.plctalk.net/qanda/showpost.php?p=55623&postcount=15

http://www.plctalk.net/qanda/showpost.php?p=55566&postcount=5
Norm's cabinet, I think, is floor mounted (no legs) so it will be easier to access the terminals without being close to the devices.

Eric's is smaller and I am sure is mounted at eye level, again easy access without proximity to devices.

Here is an example of what I DO NOT LIKE to see.
http://www.plctalk.net/qanda/showpost.php?p=55587&postcount=9
The Drives and terminal strip are on the bottom of a floor mounted cabinet....you either lay or sit on the ground when there is a need to work in the cabinet....I have an aversion in not having the freedom of movement in case of a problem.
NOTE: The cabinet is nicely done and I mean no offense to the builder, I personally just do not like this kind of layout.

As far as spare space goes that would depend on circumstances, I attempt to have more space available regardless...too many variables in the industry. Just recently an engineer I worked with did the layout on a cabinet using an SLC500 with expansion chassis, he did not look at the cable length for the expansion and designed the panel "real tight" but with the racks far apart ...the sad part is I tried to explain the problem and he would not listen...standard engineer thing. He had to purchase another cabinet and do a new layout.

This is my personal opinion based on having to work on panels for over 30 years in numerous situations and conditions. The better part of that 30 years was DEFINITELY outdoors in rain, snow, tornadoes, hurricanes and anything Mother Nature could use.

I do not know much but know what I like and what I dont like.

This panel is not floor mounted but hanging on a skid