ABB ACH550/Eclipse Bypass Start Problem

[jogas]

I've got two ABB ACH550's we're commanding via AX V3.4.43/ Modbus RTU. Both VFD's will take the Speed command instantly, but will not start when commanded. In one of my previous posts, Jeff provided a Table(thanks) for the ACH550.
As I have never had to work on the protocol packet level (yet), I do not know how to "set bits high".
Any care to educate me?
I've attached the Table for reference.

[cal-cu]

You should be able to write 0x04fe to 40001 and then 0x04ff. This the Hex to turn on correct bits.

[joey791]

How are you doing this now?

I have a friend that has done Modbus to ABB but I dont remember him sending to all the bits, but this wasnt using AX. I will see if I can find his program and what he was sending to the drives.

[jogas]

How are you doing this now?

I have a friend that has done Modbus to ABB but I dont remember him sending to all the bits, but this wasnt using AX. I will see if I can find his program and what he was sending to the drives.

Thanks for the reply.
I've atached some pics of the wire sheet and Driver Property.
I'm trying to marry up the ABB Table to the AX ModbusAsyncDriver....and learn the Modbus protocol thoroughly along the way.
Later on, I may have to bring in some AI's via the ABB VFD /Modbus.
Jogas

[joey791]

Jogas I know with ASI we would write a 1 to register 40001 to cut the drive on and a 0 to register 40001 to cut it off.

Also depending on how your registers match up you might have to add a 1 to the register. So if you want write a 1 to 40001 you may actually have to set it up to register 40002 to write to 40001.

Again this is with ASI and not AX.

Also you said you are sending the speed constantly. I would set up a logic to send the speed reference after the start/stop command because I have seen some drives fault out because they have a speed reference but not a start/stop.

[jeffk91467]

Hey Jorgas,
When I was using a software command to start/stop the drive, I was writing an integer value (SINT) to register 40001. Our Modbus Interface software also allows us to write to a specific BIT in the register also, but by writing the total value of which bit's are on/off I am only sending one command in place of sending a command to each BIT. (We are charged per integration point, so it is easier/cheaper to write to one point for my front-end).

So to enable the drive, I would send a value of 1278 (To register 40001)which would be the total for setting BITS 1, 2, 3, 4, 5, 6, 7 & 10 HIGH (Or ON). Then to start the drive, I would send a value of 1279 which would be the total for setting BITS 0, 1, 2, 3, 4, 5, 6, 7 & 10 HIGH (Or ON).
You could also send an ON command to (register 40001) BIT 3 to enable the drive, then send an ON command to BIT 0 to start the drive. (Note: The 1278/1279 value was calculated using the full Control Word from ABB's manual. That table I sent does not show what all the bits are and what they do.)


I am unfamiliar with the AX modbus interface, so I do not know what method is easier for you.

One thing to be aware of is if someone kills power to the VFD, once power is restored, the drive will not restart until you resend the drive enable, then the drive start command. When power is lost, the cache containing the modbus commands is cleared. So you need to monitor Modbus comm and on a loss of comm, then when comm is restored you need to resend the enable/start commands. (You could probably also accomplish this on a motor status failure to trigger the restart process).

[jogas]

After a weekend of Googling anything Modbus RTU, I reviewed the Driver setup and was convinced it was configured correctly.
I then looked at the ABB Parameters and found Parameter 5305 set to ABB Lim Drv, which sends the VFD an OFF1 and an OFF2 with my Modbus commands. Changed both VFD's to DCU Profile....BINGO.
I called the ABB startup Rep who set everything up (and was convinced it was the Modbus Driver's fault), and told him what I found. He congratulated me on finding the problem.
Two lost days of head scratching... :mad:

[ddcfreek]

After a weekend of Googling anything Modbus RTU, I reviewed the Driver setup and was convinced it was configured correctly.
I then looked at the ABB Parameters and found Parameter 5305 set to ABB Lim Drv, which sends the VFD an OFF1 and an OFF2 with my Modbus commands. Changed both VFD's to DCU Profile....BINGO.
I called the ABB startup Rep who set everything up (and was convinced it was the Modbus Driver's fault), and told him what I found. He congratulated me on finding the problem.
Two lost days of head scratching... :mad:

It's funny sometimes how factory guys can do no wrong.... at least until you prove them wrong.

[GTSDave]

jogas,

I just saw this thread, and could have probably helped you on this one. We were using Modbus with ACH550's and E-Clipse bypasses on some OAHU fans and had issues with the drives going into ramp hold mode and not ramping up. The controls techs were using the internal ACH550 PID to control static pressure, and Modbus for all control and monitoring of the drives.

The fix for us was to go to DCU profile and everything cleared up. That one had me scratching my head for a little while, but once we ironed it out, it really worked out nice for the customer.

Ever since then when working with Modbus, we use either DCU profile or Drives limited depending on what the application is, and whether or not they are going to control via Modbus, or just Monitor. It is nice to be able to choose depending on the needs of the controls folks.

Unfortunately there are still lots of folks that have not run across this when starting up customers E-Clipse drives. We start nearly 2000 ACH550's per year here at out shop, so this one came up fairly early on for us when E-Clipse was introduced. Not every shop starts the volume of units we do, so it could be your startup folks just didn't know they had a choice. I believe so much emphasis has been placed on other protocols, that most folks don't dig in and learn the ABB Modbus interface the way they used to.

Sorry you had so much trouble, I guess I should check the forums more often. Of course Jeff should always be the go to guy hehehe as he has helped me in the past. I am not a factory guy, but we do work very closely with them, and we are ABB DSS certified.

-Dave

[jogas]

jogas,

I just saw this thread, and could have probably helped you on this one. We were using Modbus with ACH550's and E-Clipse bypasses on some OAHU fans and had issues with the drives going into ramp hold mode and not ramping up. The controls techs were using the internal ACH550 PID to control static pressure, and Modbus for all control and monitoring of the drives.

The fix for us was to go to DCU profile and everything cleared up. That one had me scratching my head for a little while, but once we ironed it out, it really worked out nice for the customer.

Ever since then when working with Modbus, we use either DCU profile or Drives limited depending on what the application is, and whether or not they are going to control via Modbus, or just Monitor. It is nice to be able to choose depending on the needs of the controls folks.

Unfortunately there are still lots of folks that have not run across this when starting up customers E-Clipse drives. We start nearly 2000 ACH550's per year here at out shop, so this one came up fairly early on for us when E-Clipse was introduced. Not every shop starts the volume of units we do, so it could be your startup folks just didn't know they had a choice. I believe so much emphasis has been placed on other protocols, that most folks don't dig in and learn the ABB Modbus interface the way they used to.

Sorry you had so much trouble, I guess I should check the forums more often. Of course Jeff should always be the go to guy hehehe as he has helped me in the past. I am not a factory guy, but we do work very closely with them, and we are ABB DSS certified.

-Dave

I appreciate the reply and info.
The startup Tech admitted he was not familiar with Modbus, so that's why I didn't make a lot of noise on the job. I was surprised though, because I always thought Modbus was the VFD default Protocol. Maybe I'm out of date on that ASSumption?

[Elemental]

Hi,
I've tryed to start ACS355 by modbus control register but it was impossible to make it run.
I set the appropiate value on control reg, but nothing happened and status remained at 0000h. It's just like if some parameter were wrong and so the drive didn't respond to modbus control.
I used ABB Drives Full. I've seen that communication works well as I can write and read to registers... Really I can't imagine what's going on with this.
Do you think I will be able to solve this if I change to DCU profile? Main problem is that I will need to go to another city to make the tests so I need to be sure of what to do first to going there.
Do you know any simulator program which I could use to make some execitacion on ABB drives control first to going with the real one?
I you know any extra documentation on modbus with ABB drives appart from the device's user manual I would be pleased to know about it. Can't find anything useful in the ABB site.
Thnaks so much!