Specifications

Operation

The data recorder sampling period can be read with the RTR? command.

The answer gives the value of the Data Recorder Table Rate parameter (ID

0x16000000) whose default value is one servo cycle. You can cover longer

periods by increasing this value. Use the RTR command or change the

parameter value directly.

The current data recorder configuration made with DRC and RTR is saved

with the WPA command, in addition to the current parameter values of the

E-517 and other settings (see the WPA description for details). When the

controller is powered down, the contents of the data recorder tables and all

settings which were not saved with WPA are lost.

3.5.2 Application Example: Frequency Response

Measurements

Mechanical resonances of the system may exaggerate the response to

certain frequencies in the control signal. To determine the resonant

frequencies of the mechanics, use the E-517 data recorder to observe the

system response to an impulse in open-loop operation.

NOTE

Very stiff mechanics, e.g. S-325, S-316, P-8xx or P-2xx, have resonant

frequencies of several kilohertz. With such mechanics, the frequency

response measurement described below will not deliver meaningful

results since the sensor bandwidth of the system is limited by the

hardware settings on the E-509 analog sensor/servo module.

Meaningful results can only be attained with mechanics whose

resonant frequency is ≤ 1 kHz.

Proceed as follows for the axis whose resonant frequency is to be

measured. In this example, the resonant frequency of axis A is to be

measured:

1 Make sure the mechanics is mounted and connected to the piezo

control electronics in exactly the same way as in the application.

The load on the mechanics is especially important.

2 Start PIMikroMove™ on a host PC connected to the E-517 (see the

PIMikroMove™ software manual on the included CD for details).

3 In the

Command Entry window of PIMikroMove™, deactivate the

digital filtering of the sensor signal for the sensor channel which

belongs to the measured axis. This is recommended to achieve

more reliable results. In this example, you have to do this for the

first channel:

Send: SPA? 1 0x05000000

to query the current filter type setting, response should be 2 (= FIR

filter; default setting of the Digital Filter Type parameter)