And now - for something completely different


Thread Starter

R A Peterson

Put your project manager hats on and estimate the engineering hours required for the following project. This is based on a project I have nearly finished, so I will know the answer soon. I'd be interested in the groups estimates, and their method of determining those estimates. Project deliverables: 1) Detailed written description of the control system and how the equipment functions (70 pages). Includes detailed description of all OI screens and functions, detailed sequence of operation of each piece of equipment, and alarm descriptions. This document is the basis for PLC programming and is derived from the Process and Instrument Diagram (nine "D" size sheets) and a basic sequence of operation (about 20 A size sheets). most of this was written from scratch, perhaps 20% was taken from an existing document. Document delivered in Word97. 2) Operator interface programming (36 screens). Fifteen of the screens are for display, control, and tuning of PID loops. One screen for a loop that is not PID (mostly a feedforward type control). The rest of the screens are for control and display of the process equipment status (valves, pumps, mode), and control and display of the regeneration and neutralization systems. All screens drawn from scratch, although there are manay screens with chuncks that are similar and the loop screens are very similar to each other. 3) Detailed tag list for all screens (54 pages). used so customer can program his DCS system for remote viewing and control. includes description of each point, its PLC address, its tag name, and numeric ranges (e.g.-0-100 PSI). Document drawn up from scratch in Excel. 4) PLC programming. PLC is an AB SLC5/05. PLC has both local and remote I/O. Local I/O consists of (5) 8-channel analog input cards, (5) 4-channel analog output channels, (3) 16-point digital output cards, and (3) 16-point digital input cards. Remote I/O consists of (16) drops, all block I/O. About half the blocks are 16-point dgital output blocks, the reset are combination 8-in/8-out blocks. RSLogix500 software. All code written from scratch. BTW, I am not quite done with this part of the project yet and there are well over 1000 rungs of code already (think of this as a big hint). 5) Checkout of control system including debug of software components. Does not include point-to-point wiring out (this is by others). Does include software checkout of the entire system and functional test of all I/O and equipment located in the remote I/O enclosures and the main control enclosure. Does not include any calibration or functional check of field isntruments such as pressure xmtrs, but does include functional test of all solenoid valve operated on/off valves and control valves. Process description: 2000 gpm boiler makeup and 2000 gpm condensate polishing system consisting of (3) cation exchangers decarbonator (3) anion exchangers (5) mixed bed exchangers caustic regeneration system acid regeneration system (2) waste neutralization systems some misc stuff (15) PID loops (1) feedforward loop (22) pumps and blowers (approx. 100) on/off valves equipment is designed so that it can be run (selectively) fully automatic (no operator attention required at all), semiauto (some operator attention), or manually (even more operator attention). I'd be curious. Is this enough information for you to estimate the total hours required. If so please give us your best estimates for the project in two phases. Phase I: Deliverable items #1 through 4 Phase II: Deliverable item #5 If you need additional information to make a wise estimate, ask away. Lets see who can guess the closest to what it actually takes. I should be done with Phase I by Monday, so we will know the answer to that part of the problem soon.

Steven Landau

If you did it in IEC-1131 programming SW it would take alot less time. You can use custom function blocks for manual overrides in a single function instead of multiple rungs per I/O point. Steve Landau VP Controls & Automation SPEC 92 Montvale Ave Stoneham MA 02180
I am not in the process industry, but I have done some small process type projects. I cannot resist at least taking a flying stab at it, at least to help me refine my estimating skills. I think that you have enough information, assuming that you are familiar with the process and equipment. Drum roll please... Phase 1: 900 hours Phase 2: 300 Hours These are quick and dirty numbers, but for better or worse, this is how most people that I know do their quotes. I assign hours in blocks of 100 to each section and then add them up. I typically round up to hopefully cover any unforseen surprises. Of course, being a one man show, I would never even quote such a large project. I think that it would take at least 3 or 4 people to properly accomplish such a project. You need a PLC programmer, a MMI programmer, and a project manager, and maybe a tech or two for startup. Lets see if I starve or get laughed out, Bill Sturm

R A Peterson

Well, so far I have had but two brave estimators. I expect to complete phase I of this project in the next day or two. Once I am done, the time to guess will expire and I will post the results. I will say one thing, based on the two estimates I have received, the estimators appear to feel the project is more difficult and time consuming then it really is. One hint: 1700+ rungs of PLC code have been written so far, along with the 38 OI screens. The OI is complete, the PLC code will be complete tomorrow (I think). I am mainly curious about how you estimate hours, not so much the actual estimate, and whether the brief description I gave was adequate for quoting purposes. If anyone that has not yet put in their guess wishes to do so and needs the original description of the project, email me off list and I will send it to you.
1700 rungs of *un-tested* code??? An OI that has passed muster with the operators??? If you answered in the affirmative for either question, I think it is naive to believe that the hours expended thus far can be considered *real*. Ken Brown Applied Motion Systems, Inc.
> it would take at least 3 or 4 people to properly accomplish such a project. You need a PLC > programmer, a MMI programmer, and a project manager, and maybe a tech or two for startup. I agree with the number of bodies required - at least there in decent proportions! I have been involved in a dairy job recently in which our plant had 5 small plcs each 125DIO/15AI, 2 Med plcs each 300DIO/50AIO, a complete suite of electrical control panels (100 starters), variable speed drives, explosive gas detection system - shutdown system, and our team was as follows: 1x sales/project eng. 2x projects/contract control engineers 1x Mechanical Design Eng. 1x Mechanical CAD 1x Electrical/electronics/CAD/software/hardware/ cabling/scada design engineer. Guess which one I was? The whole thing (mechancial installation) had to be in place within 12 weeks. Its now ready for commissioning, which is just I've booked a lonngg holiday.... :)

R A Peterson

> 1700 rungs of *un-tested* code??? An OI that has passed muster with the > operators??? If you answered in the affirmative for either question, I > think it is naive to believe that the hours expended thus far can be > considered *real*. This project is for an OEM I have a LOT of experience with. My guess is it will ship pretty much working the way I wrote the description of operation. I do not expect that there will be much in the way of changes in operation or screen displays. As for the untested code, I find that most of the problem with code is not the code but that the programmer is writing code on the fly, with no written description of how the thing is supposed to work. wrting code is much easier and faster if you have a written description of how the thing works. As of right now, about 1/3 of the hours expended has been used for each of the following: * written description of operation * screens and tag list * PLC programming I expect the checkout (here at the factory) (phase II) will total perhaps 1/3 of the hours expended to complete Phase I. I would break the checkout phase into three parts: 1) Hardware. making sure all the stuff in the cabinet works (does not include any point-point wiring checks). Getting everything communicating. making sure all the I/O functions. 2) test out screens. 3) check PLC code. I expect about 1/2 the total checkout time will be spent on item 3. I expect that most of the code will work the first time, with the usual typos, and brain fades. I do not expect to make significant changes to the code, or the description of operation during checkout.

Power Plant Engineer

I guess that I am jumping in here a little late, but I need all the practice that I can get considering I am always over budget and behind schedule on all of my projects. I have some DCS experience but I haven't had any experience with SLCs, so I'll have to kind of wing it on that part. Here is how I would estimate the project. Phase I. Part 1 - If you write as slow as I do, I'd say 160 hours for this part. Part 2 - 80 hours on the screens. Typically screens are the easy part. Part 3 - Usually most PLCs and DCS systems have the ability to dump out I/O lists. So I'd say 8 hours on the Tag List. Part 4 - Programming the control logic. It sounds like you will have about 2000 Rungs. I'd say 120 hours for this part. Phase I total with contingency = 400 hours Phase II. Part 5 - System Checkout should be a walk in the park if you have done your homework. Should have a few bugs...that's normal. I'd guess 40 hours of your time with 20-40 hours of help from a tech. Then I'd double that time for unforseen events and extra features that they decide they need. Phase II. total with contingency = 100 hours of your time, and 40 hours of help from a tech. To Recap: Phase I - 400 hours of your time Phase II - 100 hours of your time, and 40 hours of tech help. I felt that the info and project breakdown that you provided was sufficient information....but then I'd probably lose my shorts on this job.