Cerbo GX Mk2 as chain counter?

[HeadedToTexas]

I see the Mark 2 adds, among other things, pulse wave counter input protocol for digital inputs. I suspect that is typically for flow meters like water or fuel, but chain counters work in a very similar way. Anyone using their Cerbo GX Mk2 as a chain counter?

 

[Mark Room]

Seems like it should be possible with a little custom code. If you aren't personally handy with that, you might be able to find someone to write the function for you either through the local installer company or Victron's software integrator program.

 

[HeadedToTexas]

I believe that signal integration code is what the GX Mk2 does right out of the box. My understanding is that the pulse wave input type new to the Mark 2 model means that the Cerbo will accept the signal created by a magnet on the rotating gypsy passing a Hall Effect sensor on the windlass. If the K-factor is set to the length of chain moved per rotation and the unit are set to feet, then the Cerbo should record the length of chain deployed. And if the Cerbo is networked to an MFD, the length of chain deployed should display on the MFD.

 

[JackConnick]

ChatGPT can write code and scripts for Venus OS, etc.

 

[Barking Sands]

I believe that signal integration code is what the GX Mk2 does right out of the box. My understanding is that the pulse wave input type new to the Mark 2 model means that the Cerbo will accept the signal created by a magnet on the rotating gypsy passing a Hall Effect sensor on the windlass. If the K-factor is set to the length of chain moved per rotation and the unit are set to feet, then the Cerbo should record the length of chain deployed. And if the Cerbo is networked to an MFD, the length of chain deployed should display on the MFD.

Good catch. I never noticed that. I already converted my tachometers to a signal provided by 2 magnets on the front balancer and a hall effect sensor. In theory I can get RPM data to the Cerbo and then MFD. I will have to explore this more.

 

[Helmsman]

I see the Mark 2 adds, among other things, pulse wave counter input protocol for digital inputs. I suspect that is typically for flow meters like water or fuel, but chain counters work in a very similar way. Anyone using their Cerbo GX Mk2 as a chain counter?

ChatGPT thinks so. This has references built in. Follow on questions would allow for a more incisive view. The one limitation is a requirement for a manual reset. I am not sure how it would handle pulling the chain back in for any reason. Anywho, here is what it replied.

Yes — you can use a Victron Cerbo GX MK2 as a chain/rode counter (or other counter) using its pulse-counting digital input feature, but there are some important details and limitations to know.

---

What the Cerbo GX MK2 Supports​

Pulse Counting on Digital Inputs​

• The MK2’s digital inputs can be configured as pulse counters (“Pulse meter”) and will count pulses — this feature is supported on the Cerbo GX MK2 (and Ekrano GX/Venus GX) but not on the original Cerbo GX. Victron Energy+1
• This means you can feed a pulse signal (from e.g., a reed switch, hall sensor, open-collector output, flow meter, shaft encoder, etc.) into a digital input and have the Cerbo count the pulses.

Configuration & Display​

• In the Remote Console (or VRM/Local UI), go into Settings → Integrations → Digital I/O to assign an input as a Pulse meter.
• You can set a multiplier that converts pulse count to a meaningful unit (e.g., chain/rode length, liters, revolutions, etc.). Victron Energy
• The counter reading will appear in the device list like any other sensor.

---

Typical Setup for a Chain/Rode Counter​

1) Physical Sensor​

You’ll need a sensor that closes/open pulses each increment of chain movement:

• Reed switch on a link wheel / proximity switch
• Hall effect sensor with magnet
• Open-collector pulse output

Ensure the sensor matches the Cerbo’s digital input electrical requirements (open-collector or potential-free contact recommended). Victron Energy

2) Wiring​

• Connect the sensor output to one of the digital input pins on the MK2.
• Common practice is to use an optocoupler or open-collector transistor output for reliable logic switching.

3) Configuration​

• In VenusOS UI / Remote Console:
  • Set the input Function → Pulse meter
  • Set Multiplier (e.g., chain link length per pulse)
  • Optionally set labels/units (e.g., ft or m)

4) Monitoring​

• The pulse count will show live in the device list and can be graphed in VRM if you’re sending data to the Victron Remote Management portal.

---

Important Limitations & Behavior​

Minimum Pulse Width​

• Reliable counting typically requires pulses to have a certain minimum duration and clean edges. Very fast or narrow pulses may not be counted consistently. This is true of many GX devices and typical of digital inputs. Victron Energy Community Archive

Resetting the Counter​

• As of current VenusOS software (2025), there isn’t a built-in UI button to reset the counter on the device itself— you would need to reset it manually in settings or via VRM/Modbus if necessary. Victron Energy Community Archive

Units Bug (known issue)​

• If you set unit of measurement on one pulse input, the same unit might stick to other inputs — a known behavior (likely a UI/firmware quirk). Victron Energy Community Archive

---

Alternative/Advanced Options​

If the built-in pulse counter doesn’t meet your needs (e.g., faster sampling, advanced scaling, filtered counts), you can also:

• Use a microcontroller (ESP32/Arduino/RPi) to read pulses and send data to the Cerbo via Modbus/TCP or MQTT and have a DBus device show the value. Victron Energy Community Archive

---

Recap​

Feature	Cerbo GX MK2
Pulse counting on digital inputs	Yes Victron Energy
Configurable multiplier/units	Yes Victron Energy
Suitable for chain/rode count	Yes (as long as pulse signal conditions are met)
Reset counter in UI	Not directly without workaround Victron Energy Community Archive
Fast pulses support	Limited (depends on pulse width)

 

[Bmarler]

Sucks about the reset, but everything else looks easy enough.

 

[HeadedToTexas]

Meh, as all too commonly, AI gets it wrong. According to section 17.1 of the Cerbo GX Mk2 manual, "you can configure the unit and multiplier (representing the volume per pulse) and reset the counter as needed."