Author Topic: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?  (Read 5906 times)

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Offline ubrain

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #25 on: January 16, 2021, 01:14:21 am »
What I'd like to do is to automagically manage the control resistance based on this indicator voltage.
eg. As the indicator starts to exceed 2.5v, increase the control resistance to bring the output back down.

The thing is, I can think of ways to reduce the resistance as a result of increased voltage (eg. an LDR/optoisolator) but I don't know how to do the opposite.
Actually you've have got a very good idea and it might work, it just need a little twist in your thinking. Simply put, the power supply output voltage is sampled via a voltage divider, consists of a top and bottom resistor in series. You've already known how to change the sampled voltage by changing the value of the bottom resistor element. However, you can also do the same with the top element too. By reducing the value of the top element, you can mimic an increase in output voltage as the sampled voltage is now larger. The control circuit will then works to reduce the power supply output voltage as a result.

However, will it actually works? Well one won't know if one don't try. I rigged up the few parts needed and tried it on my supply. In the schematic below, the current signal from edge connector pin#34 is fed to an emitter follower made up of NPN 2N3904, with the 470R trim POT as load. It is advisable to make sure the wiper is at the NPN emitter position before testing the circuit. This current limit can be totally disabled by setting the wiper to the fully clockwise(i.e. to GND) position. The parts like NPN, optocoupler and POT values are not critical. Mine works with a 5K POT but the control range is small.

Yes, I can limit the current to 40A as the output voltage reduces from 12.2V down to 9.8V, with the POT wiper set at the fully anti-clockwise(i.e. at the NPN emiter) position. However, the current limit is gradual and it is difficult to conduct a proper test without an electronic load.
This is BRILLIANT! :-+
All the bits arrived a couple of days ago, and I've put them together on a prototype board, so I could mess around with it a bit and maybe even learn something.

The only changes I made: I used a PC817 rather than a PC817A as that's what I could get quickly. Also I swapped the 22k out for a 17k to get the transistor to trigger a little earlier in the range.
You say you got it working at 40A but with the 22k I wasn't seeing any life until >80A.

So, I have just run a full charge cycle: that's 285AH of charge put into the batteries in just 3hrs without any manual input from me  8)
Kicking off at just over 100A, current very slowly dropped toward 90A as the voltage rose. But this is OK because critically, the power output remained consistent - within the range of 1212-1250w the whole way. This is the optimal result :clap:

I had tried to set the range to max out just before full and so at about 97-98% charge, the optocoupler went fully open and current started tailing off over the last minute or so, dropping to about 50A by the time I hit 100%.

This is such a fantastic mod! And I think we're the first to have done it. Now I just need to do the final build - if only my work was as neat as yours!
Respect for your skills Sir and thanks for your efforts putting the circuit together.


I should probably stop here as I've achieved the objective but... you know how mission creep goes, right?
So meanwhile, one of these just arrived today: eBay auction: #https://www.ebay.co.uk/itm/HP-704604-001-ProLiant-DL580-G8-G9-1500W-Common-Slot-Hot-Swap-PSU-684532-B21/401795623783?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
(They accepted £30 as an offer)
It's platinum rated so 94% efficient and has a double fan to dissipate more heat. Of course the Pinout is the same.
I liked the idea of 1500w instead of 1200w / 120A instead of 90A. Am I being greedy?
I hope I can figure out how to adapt the HSTNS-PL11 mods we've done here over to the HSTNS-PL33. I mean, the model number's almost the same, so how hard could it be, eh? ::)
« Last Edit: January 16, 2021, 01:16:55 am by ubrain »
 

Offline Squidster

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #26 on: January 16, 2021, 05:04:41 am »
What a fantastic thread! I bought two of the HSTNS-PL11 Power Supplies for my ham radio shack that I am trying to do as inexpensively as possible. So far, I've spent $37.00 for two of these power supplies. I'm waiting for some resistors to arrive and will get cracking on these mods as I need a solid 13.8v for the first radio I am installing. BUT, I want the OVP to let me go up to 14.0 - 14.2, approx. to allow for the voltage spikes when transmitting on the highest wattage for this radio and have it stay on and not let the OVP to 'protect' it.  :box:

Soon as I get the required items I will put it together and report back.

As a avionics technician in the Navy I am having to chisel off the dust that is sitting on my electronics knowledge and experience from 30 years ago.

HUGE THANK YOU to eblc1388 - definitely a master. BIG thank you to all who have contributed & those who have tried and reported back - ALL of this has made me excited about the ham shack, and, not paying $145 for something that I can do for about $45 and a bit of time. Thanks to all of you, of course.  :clap:
 

Offline eblc1388

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #27 on: January 16, 2021, 07:42:32 am »
I need a solid 13.8v for the first radio I am installing. BUT, I want the OVP to let me go up to 14.0 - 14.2, approx. to allow for the voltage spikes when transmitting on the highest wattage for this radio and have it stay on and not let the OVP to 'protect' it.  :box:

If you're not as courageous as ubrain which want 14.4V output or more, then you should do the OVP mod with a different resistor value. First, connect a voltmeter to point A and slowly increase the output voltage. Record the voltage increase until the unit is tripped by OVP. This might be 13.5V or more. Turn the voltage adjust POT back a bit.

Now power off and solder a 50K VR to replace the 12K resistor(as per the above OVP mod). Power ON and the OVP would now operate with a slightly higher output voltage. Repeats the process by gradually trimming down the VR value until the OVP trips at 14.5V or whatever voltage you desire. Remove the VR and replace it with a resistor.
   
 
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Offline eblc1388

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #28 on: January 16, 2021, 08:07:51 am »
I hope I can figure out how to adapt the HSTNS-PL11 mods we've done here over to the HSTNS-PL33. I mean, the model number's almost the same, so how hard could it be, eh? ::)

Great. Please do a tear down with lots of photos. Maybe their constructions are similar and the above mods can be carried out without much changes.
 
 

Offline ubrain

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #29 on: January 16, 2021, 04:10:26 pm »
I have the schematic and a pic of the mainboard, both are attached.
Do you happen to remember where you got the schematic?
 - I'm trying to find one for the HSTNS-PL33
 

Offline ubrain

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #30 on: January 20, 2021, 03:14:59 am »
Back to the original project, the HSTNS-PL11.
My circumstance is that I'd really like to leave the PSU wired up to the batteries permanently but of course, as soon as the mains is disconnected, back-current kicks in.
My first thought was diode but to cover 100amps it would need to be quite a big one and then there's the voltage drop.

So I went relay with one of these. Weirdly though, although I bought them from that ad, I only paid £7 each. The prices seem to yoyo quite a bit on them and exactly the same thing can cost between £6 and about £25 depending which ad you click.

Anyway, I fed it with the 12v standby signal so as soon as the power is plugged in, it clicks on. When the PSU is powered though, it seems to hold its ground and there's no back-current problem.

It pulls the 12v signal down to about 11.85v which affects eblc1388's balancing circuit (which uses the same 12v feed) but only a small amount... a tweak of the VR covers it.
Being a novice though, I was wondering whether there's anything silly about what I'm doing?
For example, should I be putting a resistor in line with the relay coil or anything?
« Last Edit: January 20, 2021, 03:21:22 am by ubrain »
 

Offline Squidster

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #31 on: January 20, 2021, 03:27:02 am »
I received my resistor kit today, so I am ready to make the mods on the PL11 P/S. But... I gotta share this laughable moment.

I open the little plastic box and on the top of the little sealable bags is the first batch of resistors. See attached photos...

Last time I checked, 0 ohms is a straight wire.  :-DD :wtf: MIC (Made In China)  :-//

Pretty funny!

Soon as I get it all put together, I will report back on how it all went for me.
 

Offline eblc1388

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #32 on: January 20, 2021, 07:12:08 am »
It pulls the 12v signal down to about 11.85v which affects eblc1388's balancing circuit (which uses the same 12v feed) but only a small amount... a tweak of the VR covers it.

The 12V auxiliary power supply is 2.5A regulated. Pulling it down to 11.85V means that the relay coil has overloaded the regulator current output capacity. This is definitely not good. Please reports back the coil resistance. The relay coil is dissipating 5W of power(relay specifications, but I seriously doubted it) and is sealed within such a small enclosure. Needless to say, this relay(like all other similar car starter relays) is meant and rated for short time operation only. You'll risk melting the relay or start a fire if you keep it energised.

My circumstance is that I'd really like to leave the PSU wired up to the batteries permanently but of course, as soon as the mains is disconnected, back-current kicks in.

Normally, there are already beefy diodes installed in parallel at the output of the power supply. These diodes should block the back feed into the power supply should its AC input goes off.
   
I did a check on mine and found the PL-11 takes some 200mA from external 12.2V source. The most likely cause is the 12V cooling fan, which runs under this condition. This PL-11 supply is a bit different from other models, which takes only 20mA or nearly none at all via back feed if the input AC is off.

I would suggest the following test. With AC off, open the case and unplugged cooling fan from its pcb socket. Then apply 12V to the power supply output via an ammeter to see if the total back feed current drops to 20mA or less. If it drops then you can use a small 12V relay to switch the cooling fan off via the 12V aux supply if the AC input is off.

Regarding to your problem of 200mA back feeding, I think you may have to live with it. I'm sorry I can not propose a cheaper and better solution.
« Last Edit: January 20, 2021, 07:40:09 am by eblc1388 »
 

Offline ubrain

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #33 on: January 20, 2021, 03:57:09 pm »
It pulls the 12v signal down to about 11.85v which affects eblc1388's balancing circuit (which uses the same 12v feed) but only a small amount... a tweak of the VR covers it.

The 12V auxiliary power supply is 2.5A regulated. Pulling it down to 11.85V means that the relay coil has overloaded the regulator current output capacity. This is definitely not good.
I've checked again. I was measuring via a pin on the bread board. If I go direct to the 12v output pin on the PSU itself, I'm getting 11.92v

Please reports back the coil resistance.
It measures about 33R cold and about 43R when it's warm.

The relay coil is dissipating 5W of power(relay specifications, but I seriously doubted it) and is sealed within such a small enclosure.
It appears to be drawing 0.27A so at 11.85v that's 3.2w

Needless to say, this relay(like all other similar car starter relays) is meant and rated for short time operation only. You'll risk melting the relay or start a fire if you keep it energised.
Noted.
I just set it up and left it energised for about 40 minutes, checking regularly. Yes, it got warm but not seriously hot. After 20 mins I could still touch it and hold my hand on it without discomfort. It doesn't seem to get hotter than that.


My circumstance is that I'd really like to leave the PSU wired up to the batteries permanently but of course, as soon as the mains is disconnected, back-current kicks in.

Normally, there are already beefy diodes installed in parallel at the output of the power supply. These diodes should block the back feed into the power supply should its AC input goes off.
   
I did a check on mine and found the PL-11 takes some 200mA from external 12.2V source. The most likely cause is the 12V cooling fan, which runs under this condition. This PL-11 supply is a bit different from other models, which takes only 20mA or nearly none at all via back feed if the input AC is off.

I would suggest the following test. With AC off, open the case and unplugged cooling fan from its pcb socket. Then apply 12V to the power supply output via an ammeter to see if the total back feed current drops to 20mA or less. If it drops then you can use a small 12V relay to switch the cooling fan off via the 12V aux supply if the AC input is off.

Regarding to your problem of 200mA back feeding, I think you may have to live with it. I'm sorry I can not propose a cheaper and better solution.
No worries - thanks for your suggestions.
I can always put a manual isolator switch in if I have to. It's just that it's one more thing to remember, and hence, that I'm likely to forget sometimes. So if I can set an automated solution up that's far preferable.
 

Offline Arq1983

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #34 on: March 29, 2021, 04:40:01 pm »
Big thank you eblc1388 and all of you for help. I Have problem to start psu. What resistor did you put between pins 33 and 36? I tried 1k but wouldn't start some times. Thanks
 

Offline ubrain

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #35 on: March 29, 2021, 04:42:44 pm »
It needs to be less than 0.5k. 470R should work
 
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Offline Arq1983

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #36 on: March 29, 2021, 05:21:30 pm »
Thank you
 

Offline gwhaley

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #37 on: April 15, 2021, 10:15:04 am »
Hi eblc1388 - sorry to party hijack a thread here - when you say you have a DPS-650EB...

3. DPS-650EB 665W
   ==============
   AC On: 9.7W
   DC On: 18.32W
   Loaded: 12.13V 59.3A =719W (overloaded, max 54A)
   Wattmeter: 823W, PF=1
   Efficiency: 719/823 = 87.4%

would that be the server power supply block like those from an 'RM Dual' server. Quite rare I think - but, I happen to have a pair here and have been trying to power them up outside the server. See my github page where I've documented what little I've found so far: https://github.com/grahamwhaley/Delta_DPS_650EB.

If those are the same as the one you have, do you have details on how to power it up or the pinout? I've tried a lot of searching and comparing with similar Delta supplies, but I've not found any really comparable, or a pinout that works. My next step would be to follow a well known published multimeter procedure and start putting 1k resistors across the likely candidate pins, but that might get a touch laborious (and I need to re-solder a header I attached to do it effectively).

Any hints tips or clues appreciated - and I'll update the github pages with anything found etc.
 

Offline eblc1388

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #38 on: April 16, 2021, 10:27:40 am »
On two of my DPS-650EB units, I did the following to turn it on.

I place a short on pin T21 to 0V. Then to control the +12V main output On/Off, I just connect pin T20 to 0V via a Dupont connector. If the connector is open, the power supply's +12V is turned off. To turn on the +12V, I just push in the removable connector to the metal pin which is connected also to 0V. See image.


 

Offline gwhaley

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #39 on: April 16, 2021, 01:37:42 pm »
Thanks @eblc1388 - I can confirm that works here on my 650EB!
Well, it works on one of them. The other has the relay click on and off and immediately goes into 'orange light' error mode. I suspect I may have damaged that one during my investigations. I think that one is destined to become 'spare parts' :-(
The one that does power up then spins its fans up pretty fast after a few seconds, and they seem to stay at that speed (much as they do when used in the server chassis), even with no load attached. Not the quietest PSU I think.
I'll go update my github docs now. Many thanks!
 

Offline eblc1388

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #40 on: April 16, 2021, 04:24:56 pm »
One of my units does this too, but to a lesser degree.

With the +12V output off (T20 not connected to 0V), the green power LED flashes, but no relay sounds. I then enable the +12V output and I can then hear the internal relay clicks several times and unit powers ON. It will then remain quite normal even if I turn on/off the 12V output, with the mains connected. It does this again if I left it power off for a few weeks. I suspect there is some electrical leakage on the PCB causing this, mostly across those voltage sensing smd resistors string.

I recommend to try to startup several times with only the T21 pin shorted and see if the green LED would lit steady and no orange warning LED.

Yes, the fan in my unit spins at full speed too when I turn the +12V output ON.
 

Online Jerycho

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #41 on: May 28, 2021, 07:58:12 pm »
Hello. Thats probably my first post.
Since I have been interested in converting server power supplies to achieve cc / cv function. I came to the conclusion that to achieve this, it is enough to change the reference voltage compared to the sampled voltage from the current measurement. I like liteon server power supplies because technical documents and diagrams are available. In addition, the power supplies are available in various power options from 460w to 1200w. The price is also affordable. New power supplies can be purchased for just £ 5 apiece for the 460w option. The best thing is that each power option has the same control system, the pcb can only differ and the location of the components.
Let's get to the point.
In the picture I present an example of a control loop for the power supply.


My suggestion is to cut the reference voltage output path before the 1k resistor and change to an adjustable reference voltage, the easiest option is tl431 + potentiometer and a small capacitor. A more advanced option is to use a dac + microcontroller. Tried to use esp32 (adc as output voltage measurement + current measurement + op amp as filter, 34 pin is 60mv / A current monitor output and built-in dac as reference voltage followed by opamp). Unfortunately. The ADC in this microcontroller is very inaccurate or I just made a bad low-pass filter but achieved current regulation from 1A to the maximum. The power supply performed well, it did not squeal or make any strange sounds. I also have the test results in the form of the Vref vs output current and voltage table somewhere, and I do not have equipment for precise measurements such as an oscilloscope, dummy load etc.
In the pictures I present pcb pictures with the location of the reference voltage inputs for the current control loop and some pictures of the relative pcb boards with the location of the inputs. If there are interested people who would like to develop the topic, I can provide more details about my research and unearthed schematics.


Not quite accurate schematics for PS-2122
http://www.sector.biz.ua/docs/power_supply_schemes_10/HP_HSTNS-PL11_PS-2122-1C.pdf
Schematisc for PS-2142 in attachement.



BTW. Anyone know why compensation is made at the reference voltage input instead of at the reference voltage input? I have looked through many documents, diagrams on the control loop and have not seen a similar solution anywhere.
Regards.
 

Offline eblc1388

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #42 on: May 31, 2021, 07:57:15 am »
New power supplies can be purchased for just £ 5 apiece for the 460w option.

That's very affordable. Are you sure they are really new, and not just cleaned and refurbished units?

My suggestion is to cut the reference voltage output path before the 1k resistor and change to an adjustable reference voltage, the easiest option is tl431 + potentiometer and a small capacitor. A more advanced option is to use a dac + microcontroller. Tried to use esp32 (adc as output voltage measurement + current measurement + op amp as filter, 34 pin is 60mv / A current monitor output and built-in dac as reference voltage followed by opamp). Unfortunately. The ADC in this microcontroller is very inaccurate or I just made a bad low-pass filter but achieved current regulation from 1A to the maximum.

Yes, it will work. I have uploaded a modified schematic so others can make the modification change if they wish. I wonder if you can still maintain the same current with the power supply output connected to a very low impedance(e.g. short circuit)? Does the power supply complaints of the low output voltage and shutdown?
 
Not quite accurate schematics for PS-2122
http://www.sector.biz.ua/docs/power_supply_schemes_10/HP_HSTNS-PL11_PS-2122-1C.pdf
Schematisc for PS-2142 in attachement.

Thanks for the schematic. They are difficult to find on the internet. If you have more of the schematics by the same manufacturer, please upload them here.

BTW. Anyone know why compensation is made at the reference voltage input instead of at the reference voltage input? I have looked through many documents, diagrams on the control loop and have not seen a similar solution anywhere.

Are you asking why compensation is added at the reference voltage input instead of the actual output voltage input? My understanding is that compensation is usually added between the op amp's output and the inverting input terminal or else there will be a possibility of positive feedback if done otherwise. The connection of signals does not determine which pin should be used for compensation. Many op amps also has separate compensation pins besides the two input pins.

 

Online Jerycho

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Re: HP HSTNS-PL11 psu Over Voltage Protection voltage increase?
« Reply #43 on: June 02, 2021, 05:07:17 pm »
Quote
That's very affordable. Are you sure they are really new, and not just cleaned and refurbished units?

I think these were spare parts. Considering the reliability and the number of these power supplies, it is very likely. I bought Astec AA23340 for £ 15 which was 100% unused.

Quote
Yes, it will work. I have uploaded a modified schematic so others can make the modification change if they wish. I wonder if you can still maintain the same current with the power supply output connected to a very low impedance(e.g. short circuit)? Does the power supply complaints of the low output voltage and shutdown?

As I mentioned before, I didn't do too many tests because I don't have the necessary equipment, my test was to connect 6 car bulbs 60w each in parallel.
The power supply worked well, it only sizzled slightly when the reference voltage was close to 0v, I suspect it was due to the quality of the pcb. The power supply did not turn off at low voltage because I turned off the uvp protection, so voltages close to 1v were available when the reference voltage was also low


Quote
Thanks for the schematic. They are difficult to find on the internet. If you have more of the schematics by the same manufacturer, please upload them here.

Sure, I took some time to do it, it was not very pleasant because I was wandering around Chinese forums typing keywords in Chinese search engines but I found interesting documents. Unfortunately, only preview demos are available, the service on which I found the documents is payable at the moment, when I was doing the search, they were available in full.
http://ishare.iask.sina.com.cn/f/5075532.html
ishare.iask.sina.com.cn/f/5075393.html
http://ishare.iask.sina.com.cn/f/5080334.html
http://ishare.iask.sina.com.cn/f/5075478.html
http://m.ishare.iask.sina.com.cn/f/5074978.html
http://ishare.iask.sina.com.cn/u/53b4cea411e0ee10dc4a362f/
Here is directory index
http://ishare.iask.sina.com.cn/u/53b4cea411e0ee10dc4a362f_downNum_pdf_1/
Also see atachement.
I also found a Chinese forum where someone managed to convert the power supply, but unfortunately the person does not want to share the method.

https://www.mydigit.cn/forum.php?mod=viewthread&tid=183810
https://www.mydigit.cn/forum.php?mod=viewthread&tid=229111&extra=&page=1
https://www.mydigit.cn/forum.php?mod=viewthread&tid=217015

Quote
Are you asking why compensation is added at the reference voltage input instead of the actual output voltage input? My understanding is that compensation is usually added between the op amp's output and the inverting input terminal or else there will be a possibility of positive feedback if done otherwise. The connection of signals does not determine which pin should be used for compensation. Many op amps also has separate compensation pins besides the two input pins.

Thanks for the answer.


 


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