Merlo Loader: Replacing Damaged Hydraulic Pump Controller with Two Relays

I finally wrote the program. In the process of running it, it came out that the PIC16F876A processor gives a minimum PWM frequency of 1.2 kHz instead of 100 Hz and it might be a problem to fully drive the solenoid valve. I have ordered a more suitable PIC16F1717 and will try to fire it up on the Merlo machine. When it starts I will make a circuit board. By the way, I will add an option to drive the version with three solenoid valves, and a fuel-saving option (low-speed operation), i.e. full opening of the solenoid valve at about 1500 rpm. I will use BTS432 circuits as the drayers for control. The controller has a 7-segm 4-digit display, and an externally attached simple 3-button programmer with resistance division attached to the analog port. The controller has a built-in hour meter, user-programmable code to access software functions, signal parameter display for service purposes, intuitive programming of the driving potentiometer. The whole thing took me about 4 kB of code. I will get back to you at the end of June and describe further progress.
Andrew

Hello again
After several attempts with various PWM regulators, I finally found a solution that satisfies me. I used a regulator I bought as a DIY kit, the schematic of which is in this post https://www.elektroda.pl/rtvforum/topic2940955.html .The regulator required some minor modifications because it often reset when using the charger. I cut the path at leg 1 of IC2, inserted a voltage regulator for 12V/5A because the unstable voltage coming from the alternator was resetting my controller. The valve control voltage is taken from the output of transistors T2 and T4. This voltage flies to the relays, the diagram of which I posted at the beginning of this post. Further to the corresponding valve. I connected the other output of the valves to ground. Instead of the potentiometer given in the schematic (10k), I used the one from the 5k charger. I removed only two resistors, probably 1k each. In this way, I basically achieved smooth starting adjustment over the entire range of the potentiometer, i.e. from zero (pedal depressed) to 2/3 of the height the adjustment is felt.
This works in such a way that after firing the supercharger, the controller diode blinks and the voltage does not flow to the valves. When the pedal is pressed, the controller automatically begins to apply voltage and the LED lights up continuously. The voltage is zero because we have the pedal depressed, but when we let go of it the machine starts (if, of course, we have the direction lever switched accordingly). It works very well eventually. There is also an inconvenience but about that later because I have to go

Returning to the topic ...
When the pedal is depressed to 2/3 of its stroke, the charger does not respond to further release of the pedal. Probably because the voltage at the output reaches a value sufficient to drive the maximum valve (measured with a meter, it is about 8-9V) With further release of the pedal (further movement of the potentiometer), the voltage increases, but it is no longer relevant to the valve. It would be possible to lower the supply voltage of the entire controller to, say, 10V, and this is what I intend to do. This should increase the control range of the valve through the potentiometer.
The inconvenience of this whole solution is that during driving, when the pedal "clutch" is pressed, the charger immediately comes to an abrupt standstill. However, you can easily get used to this by operating the individual pedals of the loader slightly differently to get rid of this problem. When it comes to gently pulling up, scooping what is on the bucket, the controller does its job very well. The driver's transistors don't need any heatsink, the only heatsink is for the voltage stabilizer, but even that doesn't get too hot.
That's it for now, I'll play around with a lower supply voltage for the controller and I'll let you know if it's even better
Greetings.

Hello everyone, I'm on the portal since today and it's because of the SUSMIC 12 controller
namely I need a broken one of this kind

I have some two at home but they have obliterated markings. Paste some pictures of the plug and housing or send on pw

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I don't have one, unfortunately

Yes actually I only need the connector itself, I built a replacement to plug in while the original is being repaired, now the connection itself takes too long

Mine have a different connector
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well actually there is something different, thanks

Does anyone know a programmer for the controller. I need to set the speed control pedal in the program. It needs to be calibrated as the vehicle jerks when starting. Please recommend some workshop or programmer who knows the subject.

korsarz50 wrote:

Does anyone know a programmer for the controller. I need to set the speed control pedal in the program. It needs to be calibrated as the vehicle jerks when starting. Please recommend some workshop or programmer who knows the subject.

throw in search engine" mtechnics "

Added after 1 [minute]:

jantruck wrote:

Hello everyone, I'm on the portal since today and it is because of the SUSMIC 12 driver
namely I need a broken just such a driver

If the topic is still valid, I have such a broken 2005 driver

hello, yes the topic unfortunately returned if you have such a controller then please and info.
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Looking for schematic diagram for
Sauer-Danfoss MCE209B1011
id. - No. 510544
SN: 025119590
susmic12 NFPE

Hydrostatic Transmission Controller (SUSMIC 12 Analog)

Compatible with MERLO, Sambron, Matbro, Bobcat, Massey Ferguson, JCB

We offer a new analog of the SUSMIC 12 hydrostatic transmission control unit, fully compatible with the original MERLO controller (100%).
Part numbers: MCE209B1003, MCE209B1023, NFPE, 059568, 035965, 058553.

✅ Key Features:

Works immediately after installation – no complex setup required.

Increased stability against voltage fluctuations – ideal for older machinery.

Software calibration via smartphone (Android) ensures smooth movement, precise pedal response, and reduced fuel consumption.

Ability to limit maximum speed and smooth acceleration – reduces transmission wear and extends component life.

Emergency driving mode – allows the machine to move even if sensors fail (at 40% drive power) to reach the repair site.

Built-in fault diagnostics with clear error descriptions displayed in the mobile app.

📦 Package Contents:

Hydrostatic transmission controller (SUSMIC 12 analog)

Adapter for connection to factory wiring

User manual and Android software

⚙️ Installation:

Connect the control unit to the machine’s wiring harness

Install the software on your Android smartphone

Perform calibration according to the provided instructions

🛠️ The controller is ready to operate immediately after connection!
Suitable for telescopic handlers, construction, and agricultural machinery.
Warranty, connection consultation, and technical support included.

For contact email:
bobchuk(@)gmail.com
+380965770027 WhatsApp
Controllers are in stock in Poland. Shipping from Poland or Ukraine is possible.


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There are replacements for this controller on olx. They will come install give warranty.

There is a company in Poland that remanufactures Susmic 10/12 and Susmic S1X controllers. I ordered one and the other and there is no problem immediately works. They give a 3 year warranty on the controller.
http://sprzedambyka.pl/pozostale-maszyny-narzedzia/susmic-12-s1x-s5x-sx-nfpe-71841.html

Hello can you please contact me ?

Hello.

Can someone tell me where I can buy the Susmic12 controller or the equivalent from the Ukrainian company?

Thank you

Below you have a contact for the company, you can establish cooperation, or write what you need. The company is from Poland, but the calibration is done remotely via the Internet.
(Below you have a contact for the company, you can establish cooperation, or write what you need. The company is from Poland, but the calibration is done remotely via the Internet.)
http://sprzedambyka.pl/pozostale-maszyny-narz...terownik-susmic-12-s1x-s5x-sx-nfpe-71841.html

Hi, firstly apologies, I have extremely limited knowledge of electronics so I can't help with your topic of effectively bypassing the controller...... but... I have a Bobcat T40140 telehandler which had a Sauer Danfoss controller replaced with an S1X controller before I bought it at auction (the spare Sauer Danfoss I found under the seat). I am terrified of this electronic machine, so I did some homework and I believe I might have a solution. The Sauer Danfoss motor apparently can have the servo motor valves replaced with a simple hand-operated manual lever, so you don't need to worry about electronic proportional valves, just replace them with manual! Please see enclosed YouTube video, I hope this helps.
https://youtu.be/BgFrOwiZ0KU?si=SXOWYw5LLpExMt7I