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Thread: Step2Linear

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  1. #1
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    Step2Linear

    My Step2Linear boards are on the way. I am going to be converting a knee mill that had a Mitutoyo Millstar III control on it. The control consisted of Glentek 7115 Servo Amplifiers and Glentek DC brush Servo motors.

    I have a couple questions. The Step2Linear manual seems to indicate a diagram to make up the serial cable to communicate with the board yet unless I missed it, I couldn't find it.

    Secondly, the manual indicates using a center tapped 20V transformer for the power supply, after rectification does that not yield about 28VDC? Which is way over the 18VDC limit. Now if I got a 12VAC center tapped transformer, that should yield me 16.9V correct?

    I'm sure I will have some basic questions, I will ask here for everyone's benefit.
    Marty

  2. #2
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    Re: Step2Linear

    Because I have space considerations, can Step2Linear be mounted vertically to a piece of aluminum and one Step2Linear on EACH side of the mounting plate? Are there heat issues to contend with?
    Marty

  3. #3
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    Re: Step2Linear

    The power supply needs plus and minus 14 volts so the 20 volt ac yields 28 volts DC with a centertap, which is +14 and -14.
    I say a 20 volt transformer because it will usually be about 22-23 volts AC unloaded which will still be below the absolute max which is 36 volts DC.

    The boards don't produce any heat, so you can mount them anyway.

    Also i include a programming cable with the order so you don't have to make one.

    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  4. #4
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    Re: Step2Linear

    Quote Originally Posted by Larken View Post
    The power supply needs plus and minus 14 volts so the 20 volt ac yields 28 volts DC with a centertap, which is +14 and -14.
    I say a 20 volt transformer because it will usually be about 22-23 volts AC unloaded which will still be below the absolute max which is 36 volts DC.

    The boards don't produce any heat, so you can mount them anyway.

    Also i include a programming cable with the order so you don't have to make one.

    Larry
    Ah! Didn't equate Larry, HALF the 20V! Doh! (chair)
    I salvaged a +/-15VDC power supply from another control I plan to use, so I should be good there.
    Thanks for the cable, much appreciated.

    Gathering parts now. Will take pics and keep everyone posted. I do have a few questions about connections to the Glentek servo amps. I'll post them here later on.

    Thanks Larry, for putting these together and supporting them. Here is a link to pictures of the mill:
    https://plus.google.com/u/0/photos/1...52313798869265

  5. #5
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    Re: Step2Linear

    Ok, my machine has Glentek SMA7115 Servo amplifiers with a DC Buss voltage of 170V. I am in the planning stages. I have created a table that connects the SMA7115 to Step2Linear with a few questions at the end of the table:

    Terminal/Signal Name Description Step2Linear Termial
    J1-1 DIFF SIGNAL IN (+) Differential signal input Step2Linear + Ref output
    J1-2 DIFF SIGNAL RET (-) Differential signal return Step2Linear -Ref output
    J1-3 SIG IN(+) Single ended signal input
    J1-4 COMMON Common for all signals & shields Step2Linear Common
    J1-5 TACH IN Tachometer input. (not used in current mode)
    J1-6 MTR CUR Scale factor: 1V=5A Step2Linear Current Input
    J1-7 LIMIT + Inhibits motor in + direction
    J1-8 LIMIT - Inhibits motor in - direction
    J1-9 INHIBIT Inhibits motor in both directions Step2Linear Enable Output (via relay contact)
    J1-10 FAULT Goes low if there is a fault in the amplifier. May be externally forced low to stop motor rotation
    J1-11 COMMON Comon for all signals and shields Step2Linear Common
    J1-12 RESET Resets the fault latch. May also be used as an inhibit input
    J1-13 LS/ECB Goes high if the Low Speed Electronic Circuit Breaker turns on
    J1-14 HS/ECB Goes high if the High Speed Electronic Circuit Breaker turns on
    J1-15 OVERVOLT Goes high if the buss voltage rises above 250VDC
    J1-16 OVERTEMP Goes high if the temperature of the amplifier rises above the specified temp.


    A few questions:
    Servo Power Supply=170VDC. What is the value for the voltage divider resistors for the +/- Low Voltage input for Step2Linear?
    Is the current monitor output from the SMA7115 servo amplifier, pin J1-6 adequate and typical for the Step2Linear Current Input?
    Would it be suggested to use the Servo Amplifer Inhibit to hold it low until the computer/control software is on line?
    Should the limit switch inputs be fed to the computer/control inputs as well as the servo amplifier?

  6. #6
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    Re: Step2Linear

    A few questions:

    Servo Power Supply=170VDC. What is the value for the voltage divider resistors for the +/- Low Voltage input for Step2Linear?

    I would use a 15K, 5 watt and a 1.5K 1 watt in series. Take the signal off the 1.5K

    Is the current monitor output from the SMA7115 servo amplifier, pin J1-6 adequate and typical for the Step2Linear Current Input?

    probably..you could try it The step2lin only used the current input for display in vipertune at this time.

    Would it be suggested to use the Servo Amplifer Inhibit to hold it low until the computer/control software is on line?
    Yes. you need that

    Should the limit switch inputs be fed to the computer/control inputs as well as the servo amplifier?
    Are you using home switches too ? The limit switches could be all ORed together to click the Estop input on the BOB.

    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  7. #7
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    Re: Step2Linear

    Quote Originally Posted by Larken View Post
    A few questions:

    Servo Power Supply=170VDC. What is the value for the voltage divider resistors for the +/- Low Voltage input for Step2Linear?

    I would use a 15K, 5 watt and a 1.5K 1 watt in series. Take the signal off the 1.5K

    Is the current monitor output from the SMA7115 servo amplifier, pin J1-6 adequate and typical for the Step2Linear Current Input?

    probably..you could try it The step2lin only used the current input for display in vipertune at this time.

    Would it be suggested to use the Servo Amplifer Inhibit to hold it low until the computer/control software is on line?
    Yes. you need that

    Should the limit switch inputs be fed to the computer/control inputs as well as the servo amplifier?
    Are you using home switches too ? The limit switches could be all ORed together to click the Estop input on the BOB.


    Larry
    So in your "Connecting to the Analog Servo Amplifier" diagram in the Step2Linear manual, on the voltage divider, R1 would be the 1.5K and R2 would be the 15K?

    I am going to let the control take care of the limit switch inputs. Nothing to the servo amps. if there is a limit fault the controller will disable the amplifiers.

    Now that said, the controller has an "Enable All" circuit which does not go low until the computer is on line, the controller is put on line. You have an enable circuit as well. Since everything powers up, at the same time, Step2Linear will be powered up long before the controller comes up, and the amps will not be enabled until the Control is put on line. So, that said, I would imagine I could ignore the Enable Out on Step2Linear? It may have been good for you to have an optional Enable input from the controller, then each amp could have been controlled from Step2Linear. Thoughts on this?

  8. #8
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    Re: Step2Linear

    Larry,
    Step2Linear has a fault output
    Servo Amps have a fault output

    It does not appear that Step2Linear monitors the Servo Amp Fault output. SO, should my control only monitor the Fault output of Step2Linear?
    Again, it might have been nice to have a Servo Fault Input from Step2Linear

    Marty

  9. #9
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    Re: Step2Linear

    wow, its getting complex, with every module having enables and faults !

    So in your "Connecting to the Analog Servo Amplifier" diagram in the Step2Linear manual, on the voltage divider, R1 would be the 1.5K and R2 would be the 15K?
    No, R1 would be the 15K going to the High voltage and R2 would be the 1.5K going to ground

    I am going to let the control take care of the limit switch inputs. Nothing to the servo amps. if there is a limit fault the controller will disable the amplifiers.
    They will respond faster if you leave them directly on the servo amps. It will also be better to protect your machine and motors. If the S/W is not responding then the amps may crash hard.

    Now that said, the controller has an "Enable All" circuit which does not go low until the computer is on line, the controller is put on line. You have an enable circuit as well. Since everything powers up, at the same time, Step2Linear will be powered up long before the controller comes up, and the amps will not be enabled until the Control is put on line. So, that said, I would imagine I could ignore the Enable Out on Step2Linear?
    BTW, Are you running Mach3 or Flashcut ?
    Use the enable out on the Step2lin and the controller ANDED together. See in my diagram the Inhibit relay coil goes to the +16 volt . Have the Controller supply the 16 volts instead when it is enabled. That way the coil needs both signals to enable the drive. You can use a PNP transistor, or a small relay to do this.

    Step2Linear has a fault output
    Servo Amps have a fault output

    It does not appear that Step2Linear monitors the Servo Amp Fault output. SO, should my control only monitor the Fault output of Step2Linear?
    It may have been good for you to have an optional Enable input from the controller, then each amp could have been controlled from Step2Linear. Thoughts on this?
    The Low voltage input can act as a fault input. If you really wanted to, you could have a small relay shorting out that 1.5K resistor when the drive faults to make the step2lin reset. But you don't need to.
    Just have the drives Fault output go back to the controls Estop input too, just as you will have the Step2lin's Fault output go back to the controls Estop input.


    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  10. #10
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    Re: Step2Linear

    Larry,
    Is there any reason why the Enable output from Step2Linear can not go directly to the Glentek 7115's Inhibit input? You mention anding the control output and the Step2Linear output, through a relay or a transistor?
    The idea I suppose is that both must be online before enabling the servo amplifier. You show a relay in your wiring example in the instructions.

  11. #11
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    Re: Step2Linear

    What you want is for the Amp to be disabled until the Step2lin enables it.
    This is because when power is applied to the Step2lin, the analog outputs jump around for a split second as the step2lin cpu is initializing the D-A converter. After the analog is stable the step2lin then brings the enable low.

    Thats why i use a relay contact that is normally closed when there is no power to it.
    If the Enable input on the amp is Disabled when pulled high through a resistor, that would work. But you could'nt use the step2lin PowerSupply to pull it high.

    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  12. #12
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    Re: Step2Linear

    Quote Originally Posted by Larken View Post
    What you want is for the Amp to be disabled until the Step2lin enables it.
    This is because when power is applied to the Step2lin, the analog outputs jump around for a split second as the step2lin cpu is initializing the D-A converter. After the analog is stable the step2lin then brings the enable low.

    Thats why i use a relay contact that is normally closed when there is no power to it.
    If the Enable input on the amp is Disabled when pulled high through a resistor, that would work. But you could'nt use the step2lin PowerSupply to pull it high.

    Larry
    Hi Larry,
    Understood. However why the need for the relay. My Glentek servo amp has a logic level of 5V, when sunk to the common pin of the amplifier would enable it. Can I avoid using the relay?
    I sent you the docs on the Glentek Servo amp sometime ago.

    Thanks Larry.
    Marty

  13. #13
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    Re: Step2Linear

    I just looked at the PDF, but couldn't find where they described the inhibit pin ( i could be just blind).

    But if the Amp is normally disabled and is only enabled when you pull the pin low, then that should work by just connecting the S2L's enable output to it. I see the Inhibit has an internal 10K pull up already.

    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  14. #14
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    Re: Step2Linear

    Quote Originally Posted by Larken View Post
    I just looked at the PDF, but couldn't find where they described the inhibit pin ( i could be just blind).

    But if the Amp is normally disabled and is only enabled when you pull the pin low, then that should work by just connecting the S2L's enable output to it. I see the Inhibit has an internal 10K pull up already.

    Larry
    Larry,
    The Glentek 7115 Inhibit pin can be made to be active high OR low by moving a jumper on the amplifier. I will configure the pin active low and tie S2L to it.

    Marty

  15. #15
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    Re: Step2Linear

    By the way Larry, I will be using the newer AMT113 programmed 1000 resolution on my X&Y. Will be using the stock 1000 resolution encoder on Z that came on the Glentek servo motor. X&Y on my mill used Mitutoyo 102 glass scales and tachs on the servo motors.

    Have you done any bench testing with the CUI AMT113 encoders?

  16. #16
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    Re: Step2Linear

    Ok, getting back to working on my control conversion.
    Question, my Glentek 7115-1 servo amplifiers, used the SIGNAL input and used COMMON for reference. I see Step2Linear wiring diagram has +REF OUTPUT and -REF OUTPUT.
    My Glentek servo amps also have a +DIFFERENTIAL SIGNAL INPUT and a -DIFFERENTIAL SIGNAL RETURN. The previous controller (Galil) used the SIGNAL INPUT.
    Which should I use Larry? (I believe I send you the .pdf of the manual)


    Also:
    FAULT OUT is normally high and goes to ground when there is a fault?
    ENABLE OUT is normally high until STEP2LINEAR pulls it low when its ready? So I could tie it to the negative side of the coil of a smal +5VDC relay and feed the relay with 5VDC?

    Where does the +5VDC supply for the encoders come from on STEP2LINEAR? From the +/-15VDC input or from a +5VDC input (external +5VDC power supply necessary?)

    Lastly, I assume all inputs labled +5VDC are all tied together on the STEP2LINEAR board? Why is the +5VDC at the FAULT & ENABLE OUT Connector required?
    Thanks!
    Marty

  17. #17
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    Re: Step2Linear

    It looks like you have the choice. Use the differntial inputs (that match the S2L outputs) or just use the 'signal" input and the S2L +output.
    You still need to connect the common, though.


    >>FAULT OUT is normally high and goes to ground when there is a fault?

    Yes, it pulls low. This goes back to your BOB input that should be active low with a pullup resistor to the BOB +5. You can also use an Opto coupler and connect the pos side of the opto led thru a 330ohm res to + 5volt.


    >>ENABLE OUT is normally high until STEP2LINEAR pulls it low when its ready? So I could tie it to the negative side of the coil of a smal +5VDC relay and feed the relay with 5VDC?
    Yes, or use a small 12 volt relay and connect the + side of the relay to the + side of the S2L powersupply. (This way you won't get the relay spike on the 5 volt S2L buss )

    >>Where does the +5VDC supply for the encoders come from on STEP2LINEAR? From the +/-15VDC input or from a +5VDC input (external +5VDC power supply necessary?)
    It comes off the D9 encoder connector. (See manual)

    >>Lastly, I assume all inputs labled +5VDC are all tied together on the STEP2LINEAR board? Why is the +5VDC at the FAULT & ENABLE OUT Connector required?
    NO , actually the encoder +5V uses a separate 7805 regulator, so it can't load and cause a CPU reset. Also driving a long encoder cable can pick up noise.

    The +5 volt at the Fault enable can be used to drive an Optocoupler (or small relay) for those 2 signals.

    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  18. #18
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    Re: Step2Linear

    Thanks Larry,
    Actually, I am going to use the ENABLE all circuit from the Flashcut Signal Generator to turn on a relay through which your ENABLE OUT put will go through the normally open contact to the INHIBIT input on my Glentek servo ampflier. The INHIBIT input is configured be LOW to enable the amplifier and HIGH to disable it. This way, S2L will enable the amp when ready and only send the signal to the amplifier when the Flashcut Signal generator/software is online.

    I'm going to shoot you an email with the Flashcut signal generator manual. I would like you to look at the STEP/DIR outputs and confirm for me how they are to be connected to S2L.

    I am asking all of these questions BEFORE wiring things up, in order to understand and get it right the first time.

    Lastly, S2L SUPPLIES 5VDC and is derived from the +/-15VDC power supply. A separate +5VDC regulator provides encoder power via the DB9. All correct?

    Thanks Larry.
    Marty

  19. #19
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    Re: Step2Linear

    Quote Originally Posted by Marty_Escarcega View Post
    Thanks Larry,

    Lastly, S2L SUPPLIES 5VDC and is derived from the +/-15VDC power supply. A separate +5VDC regulator provides encoder power via the DB9. All correct?

    Thanks Larry.
    Marty
    I'm not sure if thats a question.
    But Yes a second 7805 (under the S2L pcb ) provides +5V to the encoder. Its all powered from the incoming +- 15 volts, so you don't have to worry about it. ( Nowhere do i say you need an extra supply to power the encoders) All +5 connections shown on the S2L are outputs.



    Larry
    Manufacturer of CNC routers and Viper Servo Drives
    www.LarkenCNC.com and www.Viperservo.com

  20. #20
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    Re: Step2Linear - Interface with Parker Compumotor BLH

    I was seeking anyone who has experience using the viper step2linear boards.
    I have a new Step2Linear board almost working with a Parker BLH150 servo drive. I have Step2Linear powered up, I've been able to establish communications, I have the low power voltage divider providing 14V to the low power connections. My issue is fooling the Parker drive to not be giving me a OVERTEMP alarm signal at the moment it is powered up. It is not hot or operational. I interpret this as a cable missing fault. The self contained drive/motor combination worked as a pair for the initial test to balance the shaft motion. Now that the encoder cable is separated and broken out to interface with the Step2Linear board, the Parker servo drive is not happy that there is not an encoder cable hooked up to its DB-25 interface.
    The encoder drive's DB-25 connections have the differential A,_A, B,_B, Z,_Z etc... It also has MOT and *MOT which are associated with OVERTEMP. I was going to try to short these two or pull them to ground or +5V with a resistor but thought I should seek some advice if anyone had any experience fooling the drives to believe the encoder cable is still hooked up to the drive.
    I am still working on the inhibit circuit for the Step2Linear but know that the drive is currently unsatisfied with the missing encoder cable. It is not providing motor power at all.

    The other way would be to use the auxiliary encoder signals from the servo drives 15-pin user interface to feed the step2linear but this appears contrary to the viper installation manual. The manually clearly shows the motor to be interfaced directly to the Step2Linear not connected to the drive's encoder input

    If anyone out there has any advice, I would be grateful. Thanks
    Adam

    pin 6-7 page 21 in section 3
    http://www.compumotor.com/manuals/BL/BLH.pdf

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