ABB AC Drive - Model ACS550

[toastedhead]

I want to run this unit through a PLC which isnt the problem. One thing I want to do is be able to control the motor speed manually with a pot through the PLC. Does anyone know which input this is on the the ACS550 drive?

 

[dpc]

Why don't you just look in the manual for the VFD?

"The perfect is the enemy of the good." -- Voltaire

 

[toastedhead]

I did. But Im kinda wingin' it when it comes to setting this stuff up.

I see AI1 which is labeled as an "External Frequency Reference 0-10V".

Would this be it?

 

[ScottyUK]

Well, that would allow a 0-10V signal from the PLC to control the drive. If they're any distance apart I'd look for a 4-20mA input on the drive and a corresponding PLC output instead.

Isn't this quite an expnsive piece of hardware to be winging it, espcecially when the manuals are available online?


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If we learn from our mistakes I'm getting a great education!

 

[toastedhead]

I have the manuals and am confident I can work this out - Im just verifying some things first.

The plan is to run a POT through the PLC for manual operation - otherwise the PLC will run the motor.

 

[CJCPE]

AI1 is used for either 4-20ma or 0-10V input. There is a little dip switch or jumper near the terminal that selects mA or V. Put J1 in the OFF position for 0-10V or ON for 4-20mA. Signal common connects to AGND and cable screen connects to SCR. SCR, AI1 & AGND are the first 3 terminals of terminal block X1. There are several AGND terminals all internally tied together.

There are configuration settings that may need to be set to tell the drive which inputs are going to be used, but there are "macro" configuration selections that simultaniously set the most often used combinations.

 

[toastedhead]

Yeah thats what Im talking about. I was referring to Macro "Alternate" from the manual.

I think this would the best set up Macro for a manual/auto PLC run configuration.

 

[CJCPE]

The macro "Alternate" is probably what you want. If you want the pot to go through the PLC and use a separate analog input to the VFD, you would probably want to set both AI1 and AI2 to 4-20mA and have the PLC convert the pot input to 4-20mA. Setting the VFD analog inputs to mA may require both a jumper / dip switch setting and a configuration setting. I will look.

 

[toastedhead]

Thats what Id do. Use the POT through the PLC and use the PLC to either "look" at the pot when in manual mode or just adjust speed with the PLC program.

 

[CJCPE]

After looking at the manual again, it seems to me that the "Hand-Auto" macro is more like what you want. The "Alternate" macro enables the forward and reverse inputs, but does not enable both analog inputs. However, the "hand-auto" simultaniously switches which analog and which run/stop inputs are in control. Manual configuration may be easier. What other PLC commands to the VFD and status signals from the VFD to the PLC do you have in mind?

 

[toastedhead]

Anything I guess. The components have been ordered but nothing has been set in stone as far as programming goes. I was thinking I just wanted to monitor VFD speed and current and tell it speed and direction. Otherwise I really dont need anything else from the drive.

 

[DickDV]

It sounds to me like you want to use a single speed source (the pot) and route it thru the PLC for some reason and have the PLC retransmit the speed signal to the drive.

Your best choice would be to stay with the factory default macro ABB Standard since this defaults to a simple two-wire (open-the drive stops; close-the drive runs), a separate forward/reverse input and the speed reference on AI1.

AI1 defaults to 0-10VDC which makes a simple 1/1 conversion in the PLC. If you would rather have the PLC link to the drive with a 4-20ma signal, you will need to do the additional signal transformation and offsetting and then set the little yellow switches at the end of the drive terminal strip toward the inside of the drive (away from the edge). That converts the input to a ma rather than a voltage input. The default will give you 0-20ma which makes the math and offsetting easier in the PLC. If you want a true 4ma for the minimum speed, go to Group 13 Parameter 01 and change it to 20% (4ma is 20% of full scale 20ma).

I don't know where the start/stop or forward/reverse is coming from but the will connect to Digital Input 1 (DI1) and Digital Input 2 (DI2) respectively.

 

[CJCPE]

The "ABB Standard" macro sets the VFD for scalor operation configures AI1 for 0-10V, DI1 & DI2 for run/stop & fwd/rev, provides analog speed and current signals and ready, run & fault contact outputs. The "Alternate" macro sets the drive for vector operation and makes DI1 & DI2 run fwd and run rev and DI6 run enable. The other I/O are the same for both.

You could use either of those macros and add the second analog input, analog input selection and set 20% input = min speed for 4-20 ma. Or you could use just one analog input and have the PLC control just one analog speed command from either the pot or the other speed control scheme.

 

[toastedhead]

"Or you could use just one analog input and have the PLC control just one analog speed command from either the pot or the other speed control scheme. "

What do you mean by this? Hook the POT through the PLC and use the PLC to either "read" from the POT or run the motor speed dependent upon whatever the PLC tells it to?

I could use 2 seperate outputs from the PLC - 1 for manual POT operation and 1 for Auto mode - and use sub routines to keep it from trying to reasd both the POT and whatever was programmed.

 

[DickDV]

toastedhead, its unclear to me whether you have two ways to control speed or only one way. At the beginning of this thread, it sounded like you were going to have single speed pot and run it thru the PLC which in turn sent it on to the drive.

Further along in this thread, it started to sound like you would have "manual" and "automatic" modes. Manual where the speed is controlled by the pot, and Auto where the PLC (without the aid of the pot) calculates a speed and sends it to the drive.

Please clarify which of these is your plan. Or maybe you desire something else. We can help you but knowing what result you desire is essential.

 

[toastedhead]

I apologize for that. The second paragraph in your post is what Im looking for.

I was going to just use ABB Standard and have 2 constant speed selections but the "bosses" are requesting more. I can set up a PLC to the ABB with no problem using the constant speed selections but when it comes to using a pot pick speeds and interfacing it all together is where I get a little foggy.

Thanks to everyone in advance for helping me out here. I appreciate you guys taking time out of your schedules.

 

[CJCPE]

You can select 3 constant speeds with two VFD inputs or 7 with 3 inputs. The inputs can be set to use any combination from 1 closed to all closed like generating a binary number.

If you are going to use both constant speed input selections and an analog input, you may need an input to tell the VFD whether to use the analog input or the constant speed input. However, the "all open" state of the constant speed input may cause the drive to use the analog input. I would need to check the manual to see exactly how that can be set up.

 

[toastedhead]

Man, youre so much help. Part of the problem when I look at the manual is I dont know what Im looking for. As a mechanical guy, Ive got little experience with PLCs. The most Ive done with a PLC is check bolt heights with an LVDT. So this is pretty new, though I think with the help of generous folks like yourself I can tackle this.

I may scrap the idea of the POT and do what youre talking about with multiple inputs. Set up lots of different test speeds and run the test bench like that.

 

[DickDV]

Toasted, it may well be that no PLC is needed. As CJCPE has suggested earlier, if you choose the Hand/Auto Macro in Parameter 9902, you get the ability to have two different configurations with the same drive---the selection being made with one switch closure on Digital Input 3 Terminal 15.

When that switch is open, the drive looks to Analog Input 1 Terminal 2 for its speed command, and when that switch is closed, it looks to Analog Input 2 for its speed command.

You will notice that the Start/Stop and Forward/Reverse is also on different terminals depending on whether that switch on DI3 is open or closed. If you want them to both be on the same terminals so only the speed command moves, let me know and I'll give you the Parameters to change.

On the other hand, if all you want is up to seven fixed speeds, then use the ABB Standard (default) Macro and we will help you configure the inputs for seven fixed speeds. The default is three fixed speeds but it is easy to change that to seven.

 

[toastedhead]

I appreciate the help fellas. I only need a PLC because I'll be monitoring some other stuff and logging some data. Otherwise - Id be down with no PLC!