Display time stopped

[Ronnies 0]

My boss wants to display on a 'secret' screen how many times a machine is stopped and the actual time it was stopped and restarted. Not only that, he wants a daily effiency report on this screen ie Monday: Run 83% stopped 17% He says he can not determine which shift is being truthful about how long the machine has run. So he needs times and days of stoppages. We have a FX2n 128MR plc and a Beijer E100 I am OK with getting a 'secret' screen by using a password to log on I have struggled with getting an accurate percentage read-out. I am using a M bit, on for run time, off for stop time and then incrementing timers. Something like; 6H 31M run / 1H 29M stopped but I have juggled and messed to try get the accurate percentage but always get weird incorrect percentages. Also, and the hardest part, I can't think of a way to display the actual time it was stopped and when it was restarted I know I can use the date and time registers for the display but - I don't know how many times they might stop/start per day, so I don't know how to lay it out on the screen. The screen is only 2 lines and the boss will have to scroll down but has anyone any suggestions how I would for instance display 6 stoppages on day 1 then 3 on day 2 with the actual times that these happened

[Crossbow 296]

Write a data table in the PLC. Each time the system is stopped, use TRD to read the time, and add the hours and minutes to the tables. Don't worry about date and seconds. Or use the day of week register to track which day it was. You can also use the HOUR command to track run hours...

[Ronnies 0]

IWell, since posting, I have had an idea. Please tell me if it will work. My boss just want him alone to see the screens, he wants evidence of when it has been stopped. He suspects the operatives are stopping the machine for no good reason. here's the idea. I have a page for each day (that will reset at the weekend) and on each day page will be firstly the percentage of run /stop Then I would have to put something like 10 stop /start times by moving the time into a register each time it is stopped and then started Then using an index to move the next time it is stopped into new registers. so The first page would look like this MONDAY RUN D10% STOP D11% STOPPED AT D20 D21 (Hour/minute) STARTED AT D22 D23 And so on 10 times If they dont stop it 10 times the figures will just show zero's Would this work? Oh, and one last question, and believe me, I have really tried How do I work out percentage If it has run for 387 minutes out of 480 minutes it could run - what's the formula? Edited 30 May 2012 by Ronnies

[waynes 8]

Hey Ronnies, To calculate the %, you divide the actual time on by the total time on. Your result will be sub 1. Ie. using your example it will be 387/480 = 0.80625. This will equate 80.6%. You can do this on the FX2N by multiplying the actual, 387 in this case, by 100 and then divide it by the total shift time (480).

[Crossbow 296]

FX2N also has floating point math, so you could simply convert the numbers to floating point and divide 387/400 without the multiply by 100. Use the table write commands for writing a table of start and stop times, since they manage the index internally.

[Ronnies 0]

Thank you both. I am writing the 'test' program and now the percentages show correctly. The table write commands are something new to me. I shall have to read my book again

[waynes 8]

Yeah of course Crossbow, that is another way to do it. I just didn't mention it as it would 'complicate' it a little bit for the user. He would have to use instructions like FLT and INT and so forth. What we typically do is to define exclusive states per machine, namely: Cycling: Set when the machine is in production Starved: Set when machine cycle cannot continue due to part at discharge Blocked: Set when no part present at infeed, and machine cannot continue Waiting Aux Part: Set when parts are not available at auxiliary part load station Waiting attention: Set when machine enters a 'fault state' Repair in progress Emergency stop Bypass Selected Tool change Shutdown Setup Mode Break No comms Using each one of the above exclusive states, the total running/ monitoring time can then be calculated. Each of the states would be a percentage of the total running time and you can monitor your total uptime in hours and minutes or as a percentage. If you do it this way you will really get down to the actual reasons why there might be possible production loss or inefficiencies, and where the stem from. Best of luck!