Synchronization

manmeetvirdi

Member
Join Date
Oct 2004
Location
India.
Posts
750
Hi There
We Have Got Two Drives(100 Mtrs Apart ) Running The Same Chain(convayor).both Of Drives Have Diffrent Gear Ratio.we Are Using Mitsubishi Fr-a 500 Series Inverters Each For These Drives.now How To Synchronize Them,both Are Needed To Start Simultaneously.
One Thing We Have Already Done Is That We Have Linked The Two Drives In Master -slave Mode.master Is Giving The 0-10vdc Signal Corresponding To The Frequency Set By Port Connected To It ,to Slave Inverter.
But We Know That There Is Frequency Offset Between These Drives(due To Diffrence In Gear Ratio) ,now How To Eliminate This Particular Problem Of Offset.
Any Sugestions??
Regards,
Manmeet Singh Virdi
 
I donno these drives but shouldn't there be a parameter where u can scale the 10 Vdc output of the master drive 0-100%?
 
The trick

Ratioing outputs will not work. Two encoders are required, one for each drive. Both drives must be able to express a scale factor in encoder counts per distance. The encoder counts must be integers and the distance is arbitrary but both drives must use the same distance. This means you need to have an integer number of counts per revolution, per lug, per meter, what ever.

The goal is to keep the two conveyors synchronized in phase for the whole day ( forever ). This can't be done unless there is some integer number of counts for converyor a to the number of counts on converyor be. If the ratio of counts between the two can't be expressed as a integer ration then these drives can't be properly geared. Eventual they will get out of phase with each other.

Given the gear ration can be expressed as a ratio between two integers then gearing should be possible with any decent motion controller.
 
Another trick . Assuming with ratio's we can get these things running near enough the same (sure they will run out after a while) , can't we use them in a torque master/follower application ?
 
??Synchronization??

hi there
Seems we are heading towards real mess !!
Lets see what we can do with encoders,but to me it seems that the two drives will eventually run out of synchronism !
Lets see.
Will again post ,of our final decision,and how its working.
Regards
Manmeet
 
Seems you know more than the people who try to help you , so one wonders why you ask in the first place ?

However - speed sychronization is not what is required , just think about the application , the drives are required to do an equal amount of work , since they HAVE to run at the same speed (being connected by a chain) , the essential thing is that they should both do equal work -
 
In this kind of application where BOTH drives are attached to the same chain, the usual solution I use is to have ONE drive run as the Master in Speed mode, and the other as a Slave in Torque mode.

This method is very reliable and easy to set up. The only extra requirement I would consider is to have some kind of trip on the Slave drive in the case the chain or conveyor should break.
 
Way Too Many Problems Begin Their Lives As Solutions

Way Too Many Problems Begin Their Lives As Solutions.

Apparently, you are trying to use two smaller motors, with two drives, rather than a single, appropriately sized, motor with an appropriately sized drive.

What could possibly be the advantage in that? You are creating un-necessary problems by using a poor solution.

Not only does the Velocity have to match, but so does the Acceleration and Deceleration.

Using a single, appropriately sized motor and drive will eliminate these problems.

I'm really curious as to why you chose this as an appropriate solution. Is it simply a case of using materials and devices at hand? If so, that is a foolish approach to problem solving.

Problems Dictate Their Own Solutions.

When a problem is truly understood, the understanding of the problem dictates the solution. Once the problem is understood, any solution, as dictated by the problem, can be applied. Now, the range of that solution can be anywhere from reasonably adequate to over-kill and onto way beyond over-kill. Any solution in that range will certainly take care of the problem. However, as the solution departs reasonably adequate and approaches over-kill, you can bet you are wasting more and more money. At what point does the investment get paid off and when do real-profits, from the investment, begin to be realized? If way beyond over-kill, the question becomes... can this investment be paid off at all? If not, then at that point, the cost of production is greater than the expected profit... the business WILL go out of business.

Now, understand, I can appreciate the idea of an intellectual challenge, totally. I absolutely love those.

However, there is a point where the amount of programming effort required to maintain consistent results in these intellectual challenges becomes somewhat ridiculous. Those independent, dedicated processes that support such ridiculous amounts of software (intellectual) support are expensive... very expensive.

The most cost effective solution is dictated by having a real understanding of the problem. It is truly that simple... What is the Real Problem? The appropriate answer will simply drop out and say, "Pick Me! Pick Me!"

In this case, I can't see why the appropriate answer is not One Motor/One Drive.

If there is, in fact, a valid reason why there simply must be two motors with two drives (for which I haven't seen any evidence), then the answer provided by PhillipW seems to be reasonable.
 
"Another trick . Assuming with ratio's we can get these things running near enough the same (sure they will run out after a while) , can't we use them in a torque master/follower application ?"
 
Philip has the simplest solution, In my view. And using two motors on a chain conveyor is often done to limit tensioning forces in the chain especially for long chains.

Set the lead drive as a speed regulator and the follower as a torque follower with the torque input signal coming from an analog output on the lead drive.

Encoders et al are nice but unnecessary on this kind of application.
 

Similar Topics

Hi All, I am trying to synch the primary with secondary, which apparently was disqualified due to Watchdog error. I am getting the following...
Replies
0
Views
878
I am running into an issue with time synchronization between a 1756-L81E and 1756-L83E. . L83E is the system time master. Enable Time...
Replies
2
Views
1,250
Dear All, I am new at this forum, seeking help from you guys and gals. Scenario: I have a Controllogix 1756-L71 5570 controller installed with...
Replies
12
Views
2,773
Dear all Iam working on a project for continuous vertical filling machine and this a video for my application https://youtu.be/coQyr06dDK8 My...
Replies
4
Views
2,133
Hi, I'm having problem with motion group time synchronization. There are 5 Kinetix drives 5500 in the motion group and each module/drive shows...
Replies
13
Views
5,987
Back
Top Bottom