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MC2 cout output PWM,

flipper80 2 years ago updated by Tim Reen 1 year ago 13
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Hello

Want to drive a D1FB Parker proportional valve withMC2 controler... Would like to know difference between PWM and so called COUT output (also said current mode and closed loop) both have to drive 24v coil. It seems they are both Pwm? BTW cannot find recommanded valve dither frequency.

Thanks for your help

Daniel

Is it OK if I move the question to an open forum topic to give an answer there? 

Hello,

 

Thanks for your reply Yes no problem for publishing this topic,

 

Best regards,

 

DANIEL.

 


Hello Daniel, the PWM and COUT Channels are indeed both Pulse Width Modulation signals. However the COUT “Current Out” channel utilizes current regulation over PWM.

It closes the loop internally to achieve your desired current output value. This should not be confused with a Closed loop circuit such as a PID loop using external pressure or speed feedback.


Regarding your dither Hz setting for the D1FB valve, I looked up the specs on the valve and found this info: http://www.parker.com/literature/Hydraulic%20Valve%20Division/hydraulicvalve/Catalog%20sections%20for%20websphere/Proportional%20Directional%20Control/Catalog%20-%20Static%20Files/D1FB.pdf

It seems at first glance all of the info is for OBE ( on board electronics) options. 

Assuming you are planning to directly drive the coils of the D1FB you will need both Recommended dither value and min max current settings. You should contact Parker’s hydraulic valve division.

Interesting! Hard to find PWM frequency in Parker literature... very strange! Its a basic and important setting! Other hyd valve supplier speak about 100 to 300 Hz? 

Hi...i am a new user here. As per my knowledge the compare outputs for each timer is on different pins so as long as you have the same period, you can have different duty cycle on each of the output pins (up to 3 per timer).  Any timer can be used for quadrature decoding and you need one timer for each decoder.

+1

The Parker D1FBExx proportional valve range (no onboard electronics versions) perform very well driving them with IQAN Modules COUT  current control.
For more detailled information on the D1FBE valves see the catalog and manuals:  http://www.parker.com/literature/Hydraulic%20Controls%20Europe/Manuals%20UK/D_1FB%205715-593%20UK.pdf, and http://www.parker.com/literature/Industrial-Systems-Division-Europe/Catalogues/Industrial%20Valves%20UK/03/D1FB%20UK.pdf.
The IQAN COUT current controlled output can control up to 2000 mA (XA2, XT2) and 2500 mA on MC4x modules, is based on PWM modulation with current measuremente and control. Dither frequency and dither amplitude need not to be adusted, just select proper PWM frequency generally listed in datasheets of the proportional valves.
For the D1FBE valves PWM frequency should be set > 100 Hz, generally we have very good performance and
low hystereses using 335 Hz PWM frequency setting in IQAN COUT channels driving D1FBE solenoids.

Note: You don't need to do build your own PWM control with timers, in IQAN the build in PWM  and COUT outputs are special designed for driving proportional solenoids.   

+1

I confirm the comments from Jos. I have found that IQAN COUT controls D1FB very well in 3 different OEM applications. The internal COUT driver in IQAN gets the spool moving really quickly and so response times are fast. Hysterisis is very low if you use the settings Jos describes.  Imins are very repeatable for fine actuator position control. It's a very good control combination.

Hello. 
I have a question about debbugging COUT problem. I have a 2 bi-directional valve, which is connected as stated in the manual:

The valve is not working as it should. I measured +17V between COUT-X and ground, when valve coil was connected to the IQAN module. When coil was not connected ( plug removed from socket) I got 22 volts.

My question is how does the logic work? Is there +24V given in the common pin constantly (COUT-X) and depending of the switching either CRET+ or CRET- is internally switched to ground?

Could i measure the PWM switching with oscilliscope? I just want to be sure that the IQAN module output is working as it should.

Thank you in advance

Actually, what you observed seems like a perfectly working installation. If you only measure voltage, you will just observe the effect of the leakage current through the output pins. 

See IQAN-MC2 user manual

If you suspect an wiring problem, the easiest method is to check the channel status in IQANdesign/IQANrun. Alternatively, you could use a break-out cable or clamp to measure the current.

Dear Gustav

Thank you for reply.

Was my understaning of switching the bi-directional valve correct (  Is there +24V given in the common pin constantly (COUT-X) and depending of the switching either CRET+ or CRET- is internally switched to ground?). And is it controlled with PWM signal?

I did not have IQANrun, I just consulted a guy who owns a machine with Iqan MC2. Is there any freeware software available to connect to the controller and check channel statuses?

Best regards,

Hi,

CRET+ or CRET- determine the direction of the valve by simply grounding one coil or the other for bi-directional functions (Low Side switch). The common output is where the good stuff comes out (current regulation over PWM). You will not read a full 12 or 24 Volts at the load because the the output is regulated according to commanded current value, I would suggest that the 17v you measured (with a 24v system) will be as high as you will see - working normally.