Low-Pass Filter visit again.

I have done the searches and the closest to what I was looking for was here- Low-pass Filter . But still no help.
My case-
About a year ago I built a control panel for a new automated manufacturing machine that has a 150W switching 24VDC power supply(DC Control wiring), D2-205 (260cpu)Plc with 64 (NPN) Inputs and 48(PNP) Outputs, all ac loads are switched via relays with DC coils, and a Cmore micro 6" Touch Screen HMI. It also has Danaher S300 Servo controller/driver within the same panel. The panel is powered by 240 3phase ac. All three phases go directly to a contactor (DC control to A1 and A2) and then to the VAC input of the Servo controler. L1 and L2 are tapped to the primary of a step-down transformer for the 120Vac Secondary as the power source for the DC power supply. I have a Cutler Hammer Powerline filter (5A) on this 120VAC prior to any devices, and all loads are switched via relay contact thru-put to loades external to the panel.
Problem-
The machine has work beautifuly as designed with only one glitch. After a few hrs of run time after the machine is turned on, the HMI stops responding on the touch screen. I can manually bring up the calibration screen via pressing F1 & F5 but there is no response the the touch panel area. I have contacted both AutomationDirect and Danaher and have been advised to find a better Filter for the box. To verify if there was a filter needed, I put an oscilloscope on the DC line. On power-up, the DC line is pure and clean at 24.4vdc. Only after the Servo controller has gone through it's selfcheck and then enables, I discover a 16KHz 2V (peak-to-peak) riding on this 24vcd signal. I have segregated all ac and dc lines the best I can. All DC conductors are shielded twisted pair with a solid neutral and earth ground using the back plate as the common ground conductor plate. When the servo motor is commanded to move (Position Control mode) this AC frequency spikes to about 5 to 6 Volts Ac peak-to-peak.
Danaher agree's that the controller is clocking the motor a 16KHz. While tuning the motor, I had to up some of the gains in order to get to position (56" ball-screw).

My research for a filter to drop out this ac fequency has not been fruitful. I am thinking of building a TEE-Form Butterworth 3 pole (L-C-L) filter myself to see if I could get a little more frequency specific.

Has anyone attempted the before?
Has anyone run into this same issue?
Or..., am I just shooting myself in the foot?
Thanks for anyone with a bit of advice.

Not going to be much help here but below is what I would give a try.

The description you are giving, especially the mention of 16 kHz, would have me trying a different 24 volt power supply, one that is not a switch mode unit, as I believe the high frequency they create is near that value you are quoting.

If you want to remain using a switch mode power supply, My suggestion would be for a higher current rating version, say double what you have already, so that there is no risk of overloading or momentary power dip.

What I am thinking of is you are striking some sort of resonace within your systems 24 volts

Good thought Gil47, I thought of doing this too until I noticed that this frequency is only present after the Servo drive is enabled. Of course it also uses this same power supply for its Digital I/o as it comunicates with the PLC. Oh, by the way..., The plc base is a 120vac unit that has an onboard DC power supply also. I do not use this DC source as it has no significant Watts. I aslo see this frequency on it also.

To me it appears you have some sort of resonance loop that is overtaking the ability of the power supply to filter it effectively, and as you don't or won't want to change the servo the easier option is to do something different to the power supply by the order of a significant step change.

Well its still only a guess on my part, but a calculated guess.

Perhaps you could try running the 24 volt system on a battery (two 12 vdc in series) to see if that might isolate the problem. Maybe it will stop the high frequency noise from getting in the wrong place.

This may sound dumb but I've seen it happen more than once. make sure something in your ladder program isn't crashing into the screen control V memory area. For instance, a counter or timer accumulator or analog input that is mapped into an overlapping area. Specifically, I've seen customers chase after the noise problem twice when it had nothing to do with it. Both of them picked up some 2-piece torroids. That high frequency 2V though not desirable, really shouldn't cause the communications port or screen navigation any trouble.

I would try a separate power supply for HMI. This should not be too hard to implement.

If that fixes it you either need to install a permanent power supply for the HMI or find a different primary power supply that will not pass along the servo noise to the hmi.

What Brand/Model power supply are currently using?

How about running the output of the DC supply through a DC to DC isolator?