Counting with Micrologix 1200

[BadgerGuy 0]

Hello Does anyone know how fast the normal counters that are inputs in the micrologix 1200 can go. I am looking for a counting rate of about 600-700Hz. Will I need a high speed counter to accomplish this or can I do it with a 1200 or a 1000 that I have sitting around. I have a panel view screen that I am going to use to display the counts and thats it. thanks Bill

[Sergei Troizky 26]

Yes, you definitely need a HSC for 600Hz.

[TimWilborne 108]

The micrologix 1000 or 1200 built in High Speed Counter will work fine The micrologix 1200 High Speed Counter can count at 20kHz. The micrologix 1000 High Speed Counter can count at 6.6 kHz. So for 600 Hz either should work fine but I would go with the 1200. It cost a little more but gives you much more capability. Remember to lower the input filters on the High Speed Counter inputs(0 and 1) to there lowest setting or they will not count Do you know how to setup the High Speed Counter Function file? Edited 22 Dec 2005 by TWControls

[TimWilborne 108]

You didn't mention the part numbers of the Micrologix you have. I forgot to state that I believe only do DC input Micrologix has the High Speed Counters

[BadgerGuy 0]

Thank you for the reply! Here is what I am trying to do. I need to count four flow meters for testing and the max speed can get up to 600Hz. I need four high speed counters. I was thinking of using the Micrologix 1500 with the HSC add on as well. I want to hook this up to a panel meter to display the number of counts that occur up until the scale I have on the tank reads 100 gallons sends a signal to the PLC to kick the solenods off. I have never used the panel view before but I am thinking it will lessen the amount of wiring I will have to do and help the user operate it better. Does ModBus mean I can reach into the 1500 for the values of the counters and display them on the touch screen? Could I also somehow have the operator key in a number that the counter should theoretically get after running a certain amount of gallons though and have the PLC do the math to calculate a percentage or do some math to find out how far off the meter is? I have been though some heavy duty PLC classes but it is still somewhat new to me Thanks Bill

[TimWilborne 108]

Your are correct. The Micrologix 1500 base unit only supports 2 High Speed Counters so you will have to use a HSC expansion module to do 4. For a simple application I would suggest getting a Panelview that supports DF1 From that point the user input you are wanting shouldn't be a problem

[Sergei Troizky 26]

High-speed capabilities is exactly what makes difference among PLC brands. Allen Bradley MicroLogix/SLC does not fit this application. I would simlpy use another brand, something like Omron or Mitsubishi. Edited 22 Dec 2005 by Sergei Troizky

[TimWilborne 108]

And how do they fit the application better?

[TimWilborne 108]

In fact I just did some looking and the Micrologix to the Misubishi are apples to apples in that size Plc. There both good but don't see anything better about eithers High Speed Counters Whats special about the Omron? But I just got thinking about it and BadgerGuy says that wants to kick some solenoid when it hits 100 gallons. If that pumps through something other than the flow switch then you don't have to sense direction and only need one input per flow switch. If this is true you can use the Micrologix 1200 base unit. Inputs 0-3 can count at 20 kHz. The Micrologix 1500 could do 8 flow switches. And yes the Misubishi can do it too but I still want to know what is so special about them Edited 22 Dec 2005 by TWControls

[gravitar 3]

You don't want to use ModBus unless you have some special need that requires it. You could get away with an RS232 Panelview (for example.. 2711-K5A5) if the panelview will be located close to the Micrologix (20' to perhaps 50' MAX cable-feet). If you need it to be farther away, you'd want a DH485 model (e.g. 2711-K5A2) and a link coupler at each end. The panelview can access and display on the screen just about anything in the Micrologix's data tables. Likewise, most things can be changed from the Panelview too. Obviously you wouldn't want to change I/O, status file bits, etc. Not only can the raw data be displayed, it can be presented graphically, as part of text messages, inside of imported bitmaps, etc. You're really only limited by your imagination! You can find out more about panelview terminals here: http://www.ab.com/eoi/graphicterminals/pan...dard/index.html

[hakko808 0]

How about the recent micrologix 1100 processor. High speed counter, analog in, ethernet, and small built in LCD. Looks to be a nice little unit, and I am condsidering one for a similar project using flowmeters and looking for feedback on them.

[Sergei Troizky 26]

Both brands suggest inexpensive shoebox units with 4 to 6 single-phase high-speed counters. I am not too familiar with Omron, but new CP1H specs look impressive. In Mitsubishi even the simplest FX1S has 4 high-speed inputs which may be freely distributed among single or two-phase counters and/or interrupts. FX1N/FX2N has six ones. BTW they already did more than 10 years ago. And you can download oldie but goldie software for free. Bingo for the subject application. Edited 23 Dec 2005 by Sergei Troizky

[TimWilborne 108]

Yes it will do the application. We probably have 40 to 50 of Micrologix and the Misubishi FX2Ns doing High Speed Counter Applications here. And last time I check the AB was doing it over 10 years ago too. But you still didn't say how they do it better. The Misubishi's inputs will count a little quicker, but in a harsh industrial environment to Outputs don't quit hold up as well. They don't seem to have the life of the ab outputs On the other hand the AB inputs are not as noise tolerant but their software is much better and much easier to integrate into the plant network I could go on and on but Mistubishi and Ab Plcs are Apples to Apples in funtionality on the small Plc Base. So how is changing to the Mishubishi going to help him with its problem. It's the equivalent of changing from a Ford to a Chevrolet.

[Sergei Troizky 26]

I realize that people from AB forum will not like this, but Mitsubishi FX series beats the MicroLogix in everything except for the programming software. Working in automation over 15 years, I have often seen AB hardware out of order and never Mitsubishi. And not mentioned but important- ML lack of online programming is a defficiency that cannot be compensated by any other advantage (if any). "So how is changing to the Mishubishi going to help him with its problem"- The answer is simple: 4 to 6 high-speed counters on Mitsu vs 1 to 2 ones on ML.

[TimWilborne 108]

Actually the Ab is 4 or 8 High Speed Counters so I'm still not sold. I agree the lack of online edits is a definate downfall on the Micrologix and there are many more and the Misubishi has just as many. We have had failures of both. The micrologix major problem is its lack of noise sensitivity on its inputs and the fact that if you short out its 24DVC it can cause the program to be losted. The Misubishi is that its outputs ar not as rugged. We have many failures of them especially on frequent pulsing of our hydraulic valves I disagree and I actually have more Mitsubishis than Micrologix so its not because I'm a diehard Ab guy. Unfortunately I took me years to get off of the "AB is overpriced and anything else is better" bandwagon So I ask you again how is the Misubishi going to help him with his problem

[Sergei Troizky 26]

On a single-unit PLC? Which one? Edited 23 Dec 2005 by Sergei Troizky

[OkiePC 14]

I use micrologix 1000s. They have 4 high speed inputs, but only one hardware HSC. Do the 1200/1500 actually have 4 high speed hardware counters built in? Thanks Paul C.

[TimWilborne 108]

The Micrologix 1200 Input 0-3 are capable of high speed counting up to 20 kHz. Inputs 4-23 are capable of high speed counting up to 1 kHz with a catch. They are scan time dependant. Our typical program scan is 2.5 to 3.5 milliseconds so I usually use 5 milliseconds as a rule of thumb. So I will only use inputs 4-23 for counting of 200 Hz or less The Micrologix 1500 Input 0-7 are capable of high speed counting up to 20 kHz. Inputs 4-23 are the same as the 1200 and are also scan time dependant. None of our Micrologix 1000s are doing high speed counting and I have never used one of them in that type of application so I’m not sure about them When you say 1 high speed counter for the 1200 and 2 for the 1500 I believe you are referring to the function file method of counting. This is only one method. BadgerGuy said the Plc was new to him so wasn’t going to get into details the other methods. The HSC function file is much easier. You can use the Micrologix 1200 for 4 single directional counters and 2 bidirectional counters. The Micrologix 1500 can be used for 8 single directional counters or 4 bidirectional counters.

[Sergei Troizky 26]

We are talking high-speed counters here, counting in scan is out of the scope. What good is 8 inputs capable of high speed counting up to 20 kHz while only two high-speed counters are supported? Edited 27 Dec 2005 by Sergei Troizky

[TimWilborne 108]

Only the upper inputs 4-23 on the 1200 and 8-23 on the 1500 are scan dependant. The function files are only an easy way to use the counters, not the only way. They make them easy to configure, turn outputs on at certain times, etc. There are only 1 of them on the 1200 and 2 of them on the 1500. We have a machine that has a 1200 on it and used the first 4 inputs for counters at a rate of a little more than 12 kHz so I know that you can use these inputs for counter. This isn't some theory to argue. The machine has ran for 3 years like this.

[Sergei Troizky 26]

So can you share the code? I think many of us would appreciate it.

[TimWilborne 108]

You argue with me saying AB would make a product capable of physically counting with 4 inputs but only capable of counting with 2 in the software and now you want me to show you how. If you had asked this question earlier instead of insisting that it could only count with two and trying to tell how every other Plc could do it better when it was obvious that you were not that familiar with the product I would post some code. But I’m going to have to say go get yourself some books and write your own

[Sergei Troizky 26]

This is just an excuse. You could prove yourself better (and ashame me better) by providing such code. I do not need it for real life- our company is an OEM and fortunately we choose our PLC brand. God save us from MicroLogix. And remember, we are talking of formal high-speed counters, not software gimmics like a "refresh and count" subroutine being called many times during a scan or similar.

[TimWilborne 108]

Ok this whole post got me curious of the true counting capablities of the Micrologix so I set up a test. The max motor rpm of my test limited my testing to 13373 Hz. I used a Controllogix M02AE as a control and tested a Micrologix 1200. Inputs 0-3 had the same values as the Controllogix at a rate of 13373 Hz Since inputs 4-23 are scan time dependant I made the program address all 24 inputs and setup a sequencer to fire all 16 outputs so the results should be realistic. Although Inputs 4-23 have a resolution of 1kHz the fasted rate I could get with it was 556 Hz. Thats about half of the physical capablility of the inputs but still not bad. I could probably strip the program down and hit 1kHz but these are probably pretty realistic since I am addressing all of the physical I/O.

[Sergei Troizky 26]

Ok, for inputs 4-23 these are expected numbers with regular counters and scan time in 1ms neighborhood. But it is still unclear what was the counting method for inputs 0-3 and whether all they were counting simultaneously.