ACS800 Motion Control

[Peter Nachtwey]

You are stating that the encoder to be used is a "line driver"(digital) type, however, 1756-M02AE is an Analog Encoder (AE) Servo Module; there is a contradiction as to what type of feedback you are going to use.

The AE in M02AE stands for analog out, encoder in. The encoder input should come from a differential line line driver.
http://www.rockwellautomation.co.kr/applications/gs/AP/GSKR.nsf/files/1756-5.47(1298)_SERVO.PDF/$file/1756-5.47(1298)_SERVO.PDF
See page 27

 

[dmargineau]

Now I could see the big picture...
What encoder type is attached to the motor driven by the ACS800?(Manufacturer-Model #)
The 1756-M02AE module's position feedback terminals are used by the Measuring Wheel; this would be the material length; why would you want to "feed" the ABB motor's encoder signals to the Analog Servo Controller?
You need the "splitter" in order to use the Main Carriage motor encoder position (Splitter Input) to provide feedback to a second system drive (Support Carriage?)
Usually PowerFlex 700S PhaseII VFDs are synchronized via fiber-optic SynchLink connection and the "master" drive is usually using two encoder interfaces; was the original setup using PF700S PhaseII drives?

 

[widelto]

This application is a flying cutoff. Splitter is used receive signal from encoder on the servo motor(line driver type), to the ACS800 drive and the 1756-M02AE board at the same time, in order to synch ACS800 drive (carriage&shear) with tracking wheel encoder (another encoder) that counts length to cut in millimeter and line speed.
Original drive was a powerflex 700S drive but the customer bougth the ACS drive.

 

[dmargineau]

I've had my hands on quite a few FCOs...
Material Wheel position/speed is always the FCO MASTER AXIS and this is the reason it was connected to the 1756-M02AE controller; you cannot "add" another signal "on top" of the existing Dynapar encoder's one.
In order to "cam" the ACS800 to the Material Wheel Axis you will have to "pick up" the ACS800 motor encoder's signal via other means, such as a 1756-HSC module and use this encoder's signal for the "error evaluation"; that's where the encoder signal splitter comes in since the ACS800 needs feedback also.
Again, what is the Manufacturer and Model Number for the ACS driven motor encoder?

 

[widelto]

No, channel 0 is measuring wheel encoder (feedback only axis), channel 1 (servo axis) is used to send +/- 10 VDC to the ACS drive, splitter picks up signals from motor encoder and duplicate them to the drive and the channel 1 of the servo board. Encoder installed on the motor is a Tamagawa. Line driver output.

 

[dmargineau]

I see... the original prints were using only one 1756-M02AE channel....
"Feedback Only" or not, your Material Wheel is the Master Axis...just for future reference...
According to https://www.dynapar.com/uploadedFiles/Products/Heavy_Duty_Encoders/RIM_SS2_Signal_Splitter.pdf
almost any incremental encoder's signal could be "split" via the RIMSS2.
Actually I have used the Dynapar 625 encoder connected to a RTAC-01 ABB module; you should be able to replace the Tamagawa encoder with a similarly accurate "mainstream" incremental encoder.

 

[widelto]

Well, As i said before my problem seems that the RTAC-01 is not speaking with the splitter. The Tamagawa is ok because the servo board is receiving pulses from the splitter, but the RTAC-01 seems not to understand them.
Dmargineau, have you ever connected a splitter like this to the RTAC-01 ?

 

[dmargineau]

Are you sure the "splitter" is functional?
Since it provides two differential line driver outputs I can't believe it canot "split" the same type signal as an input...

 

[dmargineau]

Nope...Lemme take a look at the RTAC User manual...

 

[dmargineau]

RTAC-01 "

Encoder interface:​

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CH A, CH B, CH Z, differential or single-ended​

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Output voltage 1: +24 V DC ±10%, 5 W max., shortcircuit
proof​

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Output voltage 2: +15 V DC ±10%, 5 W max., shortcircuit
proof​

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Signal levels:
"1" >7.6 V, "0" < 5 V (for 15 V supply)
"1" >12.2 V, "0" < 8 V (for 24 V supply)​

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Frequency: 200 kHz (max.)​

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Speed feedback resolution: 0.00305% (15 bits)​

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Speed feedback accuracy: 50 ppm"

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[dmargineau]

I presume you have tried another RTAC-01 with the same results...
According to the User Manual it should work...Do you have a RTAC-03 (TTL) module by any chance?

 

[widelto]

Thou I have no oscilloscope to confirm, I see dc level changes when I move motor by hand, measured at the RTAC-01 inputs, so i guess splitter is working ok. I´m using RTAC-01 power supply (24 VDC) to power output 1 of splitter that goes to ACS drive. This is because limitations on the RTAC voltage inputs 15 or 24 VDC.
On pages 3-5 to 3-9 of RTAC-01 manual you can see different types on inputs accepted by the RTAC module but line driver does not appear there. That´s the reason I suspect they are not "talking" to each other.

 

[dmargineau]

I could see an issue though...It looks like the 1756-M02 registration inputs (encoder channels) require significantly lower pulse voltages than the RTAC-01 module (1.5V OFF - 3.7V ON for the M02AE but 5V OFF -7.5V ON for the RTAC-01 at 15 VDC encoder supply power).
Do you have a User Manual for the splitter?...The .pdf I have states that the "outputs' voltages are user adjustable"...The output going to the RTAC might be too low for the module's electrical requirements...
You might need another splitter after all....

 

[widelto]

My Tamagawa encoder is 12 VDC, signals to the servo board have to be 5 VDC and signals to the RTAC-01 have to be 15 or 24 VDC. So i´m using three different power supplies. 12 VDCc for the encoder, 5 VDC for splitter output connected to the servo board and 24 vdc from the RTAC-01 for the splitter output connected to the RTAC-01.

 

[dmargineau]

You should try measuring the voltage amplitude of the RTAC received "split" pulses: they will have to be within the manual stated OFF/ON levels.
Have you tried connecting the encoder directly to the RTAC module?
Just make sure you select the 12vdc encoder supply voltage level; if the ABB module detects the pulses then the splitter is the issue.
If the RTAC cannot detect the "straight" encoder pulses, you might need to use another type encoder.