amitkumar

Thanky you

Thanks for your reply.Would I need to make any changes in i169 or the code within PMAC due to the DAC change ? Would you suggest that we put the 16 bit DAC PMAC in our application before we finalize it ?

The Pmac in my system is used to run drives in analog torque mode. Also it has a position loop superceeding it such that the position error is fed to pmac analog input with the pmac housing the speed loop. Is there a way to nullify the affect of decrease in resolution ?

At present we are using Brick controller with DAC of 18 bit resolution. But our vendor is unable to provide the same at the same price and has offered Brick controller with DAC of 16 bit resolution. Should i go for the second one in place of first one or should I go for the first one investing more money ? How much comprise I might be making if I would buy the 16 bit DAC ?

At present we are using Brick controller with DAC of 18 bit resolution. But our vendor is unable to provide the same at the same price and has offered Brick controller with DAC of 16 bit resolution. Should i go for the second one in place of first one or should I go for the first one investing more money ? How much comprise I might be making if I would buy the 16 bit DAC ?

Thank you for the reply. Ixx20 values are 0 Ixx16 values are 32 We use two motors in one axis Say motor 1 and motor 2 and a dummy axis to integrate the two say motor 5. we close the 5th axis loop by giving #5j/ and run motor 1 and 2 in open loop #1o0 #2o0. A plc is wriiten which feed the command output of fifth into motor 1 and 2 output.

Thank you for the reply. In a closed loop servo system, limiting the following error is directly tied to the following: - Motor Phasing: If you are performing commutation in PMAC, you want to make sure that you have performed the best phasing search method. We are not commutating with PMAC. The drives are doing it. - Tuning (both current loop and position loop): Tighten up your tuning. Yes we want to tighten the tuning - Mechanics: Make sure the mechanics are rigid. Mechanics are more or less rigid. - Size of Motor and/or Drive: Make sure you are not exceeding the motor or drive capabilities. The drive speeds are limited to a value much higher than the one set by PLC.Yet the amplifiers go into overspeed I don't fully understand your implementation, but a couple of other things you might want to look at: -Averaging "desired-commanded" velocities instead of "actual". This eliminates calculation quantization noise. How do we do it ? -Filtering (tracking or low pass) the analog input. How do we do it ?

we use Turbo Pmac as an integrator of two motors (with current loop amplifiers) into axis 1 and 2 providing a common speed loop which sums the speed of the two motors averages them and which acts as velocity feedback to a dummy axis 5th. The 5th axis is given an analog input which comes from an external position loop and made to position follow it. The speed of the motors change with the following error of the 5th axis.At the maximum analog input the following error is 190 the speeds of the motor are what is the speed required for the system. But if The Following error increases to 215 or 220 due to some reasons the current loop amplifiers go into overspeed. Is there a way to limit the following error value to 190 ?