GE 90-30/90-70 Elapsed hourmeter

elrese · May 26, 2009

Hi,
I am new to this site and also to the world of PLCs, I need to come up with an elapsed hour meter to keep the track of the hours the equipment is been used, this could be as high as 100K hours, incrementing by .1 hour resolution and be able to reset the elapsed hour meter.
Using a GE 90-30/90-70 PLC and programming it with Simplicity Machine Edition.
Thank you, Elrese

Controls_Engineer79 · May 26, 2009

there has been questions posted like this before the answer is to use a few running timer with a preset of 59 - units in seconds or 5900 if its in miliseconds, every time the timer cycles over you have it trip a counter which is set for 59 - thats your min - and every time that counter trips over you increment a second counter which is your hour counter, since you need 100,000 hours in .1 resolution you might need to break that up into to sets of counters - 1 that goes to 999 hours and then one that counts the 1000's

are you displaying the hours on an HMI or on a message display? because you should be able to use move comands to move the counter accumulator values to where ever your HMI message display tags will be addressed from - - - you need to give more information -- -a reset can be accomplished with a pushbutton or a hmi input to the counter reset for the hour counts.

Controls_Engineer79 · May 26, 2009

im not familar with the GE series of plcs but i assume they have timers counters - move commands and such just like every other plc - -the details migth have to be tweaked a bit but that should work

remember the counter overflow if you should exceed 32,767 which is why you most likely will need two counters to give you the resultion you need - because 100,000 with a resultion of .1 is 1 million counts

Steve Bailey · May 26, 2009

One tenth of an hour is six minutes (360 seconds). Create a TMR_HUNDS timer with a preset of 3600. Use a NC contact from the coil you put as the output of the timer in the enable line of the timer instruction. That will reset the timer when it reaches the preset. The coil will be energized for one scan.

Use a NO contact from the same coil to increment a DINT variable. The value of the variable will be the number of tenth of an hour "ticks". The accumulated value in the timer will be the fractional part of the current "tick" if you need that level of resolution.

elrese · May 26, 2009

Yes, this will be displayed on HMI which will be a panelview display and reset from ther panelview.

rwy34ils · May 26, 2009

Controls_Engineer79 said:
there has been questions posted like this before the answer is to use a few running timer with a preset of 59 - units in seconds or 5900 if its in miliseconds, every time the timer cycles over you have it trip a counter which is set for 59 - thats your min

I'm with you all the way on this except the part about a preset of 59. When the counts reach 59, the counter resets to zero, so for all intents and purposes, 59 is the same as 0 i.e there is no time interval between them. So, after 1 second, the counter will read 1, after 59 seconds it reads 59 and at that same instant it will reset back to zero. So there are only 59 intervals.

Either that or I'm losing my mind...

(8{)} ( .) · May 27, 2009

Steve Bailey said:
One tenth of an hour is six minutes (360 seconds). Create a TMR_HUNDS timer with a preset of 3600.

Gentlemen, if you're using a DINT you can count seconds pretty
safely. 2147483648 seconds works out to about 68 years.

Count seconds and tell your customer that if there's a problem in
68 years to give you a call...

Good luck,

(8{)}

.)
(Yosi)

Steve Bailey · May 27, 2009

Gentlemen, if you're using a DINT you can count seconds pretty
safely.

Yossi, you're absolutely right. Of course, counting seconds forces the person viewing the data to do some arithmetic in his head if he's making a decision based on the number of hours of operation.

I'll grant that in this case the OP could use an increment of hundredths of an hour instead of tenths, but he did specify tenths in his first post.

CowDung · May 27, 2009

(8{)} ( .) said:
Gentlemen, if you're using a DINT you can count seconds pretty
safely. 2147483648 seconds works out to about 68 years.

Count seconds and tell your customer that if there's a problem in
68 years to give you a call...

Good luck,

(8{)} .)
(Yosi)

I don't think that the GE90/30 PLC has a timer with a DINT accumulator...

Steve Bailey · May 27, 2009

CowDung,

You're right. GE Fanuc timers and counters use a 16-bit accumulator. Note that my suggested solution was to use the pulse from a self-restting timer to "increment a DINT variable". That would be an ADD_DINT function with the DINT variable as I1, a constant 1 as I2 and the DINT variable as Q.

Note also that the solution I offered will lose one PLC scan time every time the self-resetting timer restes itself. For better accuracy the OP could subtract the preset from the accumulated value instead of resetting the timer. That would preserve the fraction of one hundredth second stored in the third timer register.

Controls_Engineer79 · May 27, 2009

ya im not familar enough with GE plcs to comment on that i went with the basic timer/counter approch as an example because i knew that the plc has to have timers and counters no matter how different it is. as for if the ACC is DINT in the GE series i cant say having not programmed one

If your displaying the values on a AB panelview then it shouldnt be a problem.

GE 90-30/90-70 Elapsed hourmeter

elrese

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elrese

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(8{)} ( .)

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