Appearance
What you need
The module
One can-mdv box running the MDV firmware, product ID 010010029.
The main switch
A remotely operated battery switch driven by pulses, with two separate command coils — one to open, one to close — and an auxiliary feedback contact that reports the real position of the contacts.
All three are mandatory:
| Two coils | the module energises one of them at a time and releases both as soon as the move is done. It never holds a coil energised in normal operation. A switch that has to be held closed by a permanently energised coil is not the right switch |
| A feedback contact | wired to the module's feedback input, closed to ground while the main switch is closed. This is what tells the module the switch has really moved, and it is what the whole power-injection and boat-on/boat-off logic is built on |
| The right current rating | the switch carries the boat. The module only pulses its coils |
The relay wiring is not symmetric: one relay output opens the switch and the other closes it. Get them the wrong way round and the module will open the boat when you ask it to close — that is what ReverseSwitchDrive is for, see Commissioning.
The battery sensor
One Hella IBS intelligent battery sensor, mounted on the battery's negative post, in the variant that matches the bank:
| Bank | Sensor | BatteryIbsType |
|---|---|---|
| 12 V | Hella IBS 12 V | 0 |
| 24 V | Hella IBS 24 V | 1 |
The module polls it as the LIN master at 19 200 bit/s, a speed fixed by the firmware with no parameter to change it. The sensor is the only slave on that LIN pair: do not put a second LIN device on it. LIN is a single-wire bus and there is nothing to terminate — the module supplies the line.
The sensor is polled at the frame identifiers of its factory configuration. The module never reconfigures it, never renumbers it and never assigns it frame identifiers, so an IBS that has been reprogrammed elsewhere will not answer.
The sensor is optional in the sense that the module works without it — it just publishes no battery.
Wiring
| Connector | Goes to | Speed |
|---|---|---|
| CAN | the boat's MUXEN bus | 500 kbit/s |
| LIN | the Hella IBS sensor | 19 200 bit/s — fixed by the firmware |
| Relay outputs 1 and 2 | the open and close coils of the main switch | — |
| Feedback input | the switch's auxiliary contact | — |
The MUXEN bus is an ordinary 120 Ω CAN bus: two wires and a common ground, one 120 Ω termination at each physical end of the bus and nowhere else.
This module powers the bus
This box is a source on the MUXEN bus, not just a node. While the main switch is closed it injects power onto the bus and onto its auxiliary output; ten minutes after the switch opens it cuts both, and the bus goes dark.
That has consequences for the installation:
- The module must be fed upstream of the main switch, directly from the bank. It has to keep watching the feedback contact and be able to close a switch it has just opened; a module fed downstream would switch the boat off once and never come back.
- Anything that must survive the boat being switched off does not belong on the auxiliary output — it follows the bus power exactly.
- If the installation already has another source on the MUXEN bus, decide which one powers it. The module does not arbitrate.
The injected current
The module measures the current it is injecting and publishes it. The measurement is scaled by IMeaCoef, which depends on the shunt fitted to the board — leave it at its default unless you have a reason and a reference ammeter, see Commissioning.