Created Date: November 30,2010

Created by: brachwal

I will try to help you a little bit. I don't have much experience with Sure Servo in absolute mode but it should be same like in the other brands. The way I would do it:

1. Set all necessary parameters for the application (gains, inputs, outputs, communication,mode, etc).

2. Set system for absolute positioning mode.

3. To the first position command (P1) write ( ) - this is your home position. The example you gave will turn your servo 3 revolutions - starting from to , you will be on "the other side of your home position ", of course in absolute positioning but it will be ok in incremental .

4. The next position command(s) (P2..P8) write positions for required moves. Yes - using Modbus, all position registers might be accessed via Modbus. In my application I used the example in the manual to run/setup Modbus communication.

5. Now, using Position Command Select inputs choose desired position and then trigger corresponding move. Check the timing chart in the manual (page 5-8).

Make sure you understand the difference between incremental and absolute positioning, look at the examples in the manual. For home position you can use different values than , up to you.

I hope this will help a bit. :confused:

Need more - ask - there is a chance I can help or someone else. :cool:

Created Date: November 30,2010

Created by: BAK96

I understand what you are saying. To make things more clear by modbus you are writing the # of revs and counts to move the servo. If you write 0 revs and 0 counts my thinking is the servo probally will not move.

With other servos(Mitsubishi) I write my position commands in mms or pulses.

With Mits you can write 0 to return to the starting point. I wasn't sure if this would work with using remote registers with the sure servo. Because you are configuring you gearing and untis of measure in the PLC and not in the servo or a positioning module. If you can write 0 revs and 0 counts to return to you starting position this would be great. Wasn't sure how you would move back to your starting position after a movement command. Whether you specify the actual position or specifying the amount of revs & counts to return. If this is the case then you would have to go to the negative side for revs & counts to return. I wasn't sure. This application would be for absolute and not incremental. In the technical notes from ADC it only shows triggering a home positon request to return to starting point. I would only want to do this if homing at machine start up or if machine would stop in a position where auto restart would not be possible.

Thank you

Created Date: November 30,2010

Created by: brachwal

Like I said before, I never used absolute positioning with Sure servo. I work in different place now and don't have access to Sure Servo. The only way to check it is to try. I know is a lame answer - I hate it when someone tells me to try something when I don't have the equipment, especially tech support. If nobody else confirms returning to home position by writing then maybe is time to call tech support.

There is another crude solution which came to my mind - writing . One or even more counts sometimes does make much difference (depends on application).

Sorry I could not give you confirmed info. Could you post when you have the correct answers.

Regards

Created Date: November 30,2010

Created by: BAK96

Thank you for the responses. I am still in question of reversing direction and returning to your start point with internal index parameters with out using the home return command. If your PLC code does the math for gear reduction and sprocket, pulley diam. ect to units of measure(mms,inch,ect.)

and correlates to total revoultions parm.P1-15 and fractions revs parm P1-16

for post.1 then I would think you would have to reverse the math send those values for position 2 P1-17,P1-18. Because you are sending revolution amounts and pusle counts for fractional revs. I will contact tech support for more info. I was hoping someone has done this. All of the examples show positioning the servo from internal register but only one way of returning to the starting point. Home return. I will see what ADC has to say then repost after with results.

Regards,

Brad

Created Date: December 03,2010

Created by: BAK96

Reply from Tech support

The servo's absolute positioning is base on a zero (0) starting reference.

Setting of: P1-15 = 10 and P1-16 = 2000 will rotate the motor's shaft 10

revolutions and 2000/10000 of a revolution (10.2 revolutions).

If you want to go back to where you were, zero (0), then setting of: P1-17

= 0 and P1-18 = 0 will reverse the motor's shaft back to zero (0), its

starting point.

Hope this helps!

Created Date: December 23,2010

Created by: Kemicro

Counts being ignored

We have an application where we are using a SureServo being controlled by a DL260 CPU via Modbus. The servo is set for absolute positioning mode. Position 1 Revs and Counts are set via Modbus (eg. Revs = 2, Counts=5000). The command trigger is pulsed. The servo will move to the Revs commanded but ignores the counts. This is confirmed by the feedback signals from the servo for current revs and counts. I have confirmed that the correct parameters are being set in the servo via the servo keypad. All other commands work properly (jog fwd, jog rev, pause, home, etc). What am I doing wrong?

The other issue is that SP117 does not increment when I use a MRX command. If I use the MWX command it increments at the same rate as SP116 but all communication seems to work properly. Is there some method of confirming why SP117 increments when the MWX command is active?

Created Date: December 24,2010

Created by: Kemicro

Re:Counts being ignored

You did not answer the first question which was why are the counts component of position 1 setpoint being ignored (value is for example 5000). Why?

On SP117 I realize it should not be incrementing if communications are working properly. How do I determine why there is an communications error> All of the values Im writing are being set correctly in the servo (confirmed by checking the parameter status from the keypad on the drive). The only thing that is not working properly is that the servo will not execute the counts setting for the position. So how do I figure out what the error is?