Common mistakes — Eco Sistems gateway

General CanCan problems (LED codes, box invisible on the bus, firmware update) are in Common mistakes. This chapter is what goes wrong with the watermaker side.

Nothing at all on device/20/…

The gateway publishes only while it is hearing the watermaker. A silent topic means the second bus is not carrying anything the gateway can hear.

Likely cause	How to tell	Fix
The watermaker bus is not at 250 kbit/s	total silence rather than errors	the gateway forces 250 kbit/s at every start and it cannot be changed — set the watermaker side to match
CAN 2 wiring or termination	60 Ω across a powered-down bus	one 120 Ω at each physical end of the watermaker bus, nowhere else
CAN 1 and CAN 2 swapped	the box itself is invisible on the MUXEN bus too	CAN 1 is always the MUXEN bus
The watermaker is off or its controller is not powered	nothing on the bus at all	power it up
You are watching the wrong instance	the box was renumbered, or never was	the factory instance of the watermaker device is 0, not 255

The values freeze, then the device vanishes from the screens

The gateway declares the unit absent after 5 seconds without a frame and stops publishing; the Brain keeps the last payload for about 30 seconds before marking it stale. A watermaker that flickers in and out of the screens is one whose frames are not arriving reliably — suspect the second bus, its termination or a loose connector, not the gateway.

A command from the boat does nothing

Likely cause	How to tell	Fix
The unit is not being heard	nothing published on device/20/<n>/life	every command is dropped while the unit is absent — fix reception first
Two commands sent too close together	the second one appears to vanish	the gateway refuses anything sent less than 200 ms after the previous command; leave a second between them
Flow up/down while not producing	the unit is in standby or rinsing	those two commands are accepted only during production
Flow down already at the minimum	FlowNowRateFromMaxFlow is at its lowest	the gateway refuses to lower the flow below the unit's minimum
The command payload was not understood	the watermaker stops instead	a payload with none of the recognised keys is read as stop — check the spelling of produce, rinsing, off, productionFlowUp, productionFlowDown
The unit itself refused	the command left, but state never changes	the watermaker decides: pressure, tank level, its own safety logic. Look at the unit's panel

Remember that state is reported by the watermaker. The gateway never anticipates a command it has sent.

Two watermakers answer the same command

The watermaker device of this gateway is instance 0 out of the factory. Fit two Eco Sistems gateways without renumbering them and both answer every command sent to device/20/0, and their values alternate on the screens.

muxen-uds -i can0 scan

Each function + instance pair must appear once. Renumber one of them and reboot it — see Commissioning.

The instance number I wrote seems to be ignored

The box reads its instance numbers once, at startup. Write with --reboot, or power-cycle the box after writing.

The litre counter went back to zero

It is the watermaker's own counter, forwarded as is, and it is a 16-bit value: it wraps to 0 after 65 535 l. It also reads 0 whenever the gateway is not hearing the unit. The gateway stores nothing and totals nothing — long-term totals belong on the Brain.

The flow percentage never leaves 50 – 100 %

That is deliberate. The published FlowNowRateFromMaxFlow is trimmed to the range the unit really works in: below 50 % it reads 50, above 95 % it reads 100, and it reads 100 whenever the unit is not producing. Do not build a screen expecting 0 – 100 %.

Pressures, pumps and the hour meter all read zero

The MUXEN watermaker device can carry pre-filter and high pressure, pump and valve states, fuses and an hour meter. This equipment does not provide them, so the state topic is published with every field at zero. Read the life topic — state, salinity, flow, litres — and ignore device/20/<n>/state.

An alarm appeared and I cannot tell which

The unit reports one alarm at a time, and the gateway republishes it on device/20/<n>/error/<code>: 23 pressure too high, 24 no flow, 25 salinity too high. As soon as the unit reports no alarm, the gateway clears the faults it is holding.

The relays and the inputs of the box do nothing

Give the generic I/O device (function 17) an instance number — at 255 it publishes nothing and cannot be addressed. On this firmware it starts publishing as soon as it has a number; EnGenIo is accepted but has no effect here, so there is nothing else to enable.

muxen-uds locate does not blink the box

That routine is not implemented on this firmware; the request is refused. Identify the box by its UID (muxen-uds -i can0 uid --scan), not by locate.

WatermakerModel will not stay on the value I wrote

It cannot be changed: the firmware sets it back to the Eco Sistems 48 V model every time it starts. That is what tells the boat's screens which watermaker they are talking to.