Bosch MS4 Sport REV display

[mukesh.mehbubani]

Hi there,

The relatively new Bosch MS4 Sport ECU, does not have a specific CAN ID for engine rpm; the way the ECU software acquires the engine rpm is via series of calculations using crank, cam and segment durations... On the other hand the ECU has a pin where engine rpm can be output to an analogue logger;
a.) Is there any possibility of using this without the need of a microchip (that converts analogue to CAN) to add this function to the DA1??
b.) Considering a LDS4 display, can we also display analogue inputs and not only the ones via CAN?

Thanks a lot!

- Mk

[RickS]

There are 4 analogue inputs available to the LDS4 (0-5v) accessible through the 2nd AS connector. See the LDS4 Tech Spec, downloadable from our website for further information.

Are you sure that the MS4 does not put RPM out as a CAN ID or IDs..? Regarding the 'analogue' RPM from the Bosch unit, yes, the DA1 will only see CAN and the LDS4 has limited analogue inputs. However, once you read the RPM into the LDS4 through an analogue channel, you could pass that info to the logger by creating a CAN output message from the LDS4 I believe. This will of course depend on the format of the data that the Bosch unit sends and how the LDS4 processes it. I'll have a look into this, so watch this space.

Best regards,
Rick

[mukesh.mehbubani]

Any news??

On my side:
The message is sent across two different words, byte 3 & 4; from my understanding, by default the logger cannot read from different words therefore the parameter 'rev' named by Bosch MS4 as "rev.msb" (byte 3) and "rev.lsb" (byte 4) cannot be read.

Is anyone else running a Bosch MS4 sport with a DA1 logger? Do they have the same problem?
Regards,
- Mukesh Mehbubani

Track Testing & Vehicle Dynamics Manager
BrunelRacing

[RickS]

Apologies for not replying sooner but as mentioned above, the only solution that we have heard of for this setup is outputting the RPM message in CAN after being read by a display reading this parameter as analogue and then sending the output to CAN. Out of interest, what values do you get in 0x773 Byte 3 and Byte 4...? And how are you monitoring RPM on the dash...?

As yet I haven't had time to analyse the Bosch messages in depth but will do when I get some breathing space.

Like you, I am looking for a better solution and will post it when I come across it..!

Regards,
RickS

[RickS]

You can, of course, process and add data together from different bytes. It would be broken down into two parts of an equation, which could then be put through a 'maths sensor' to get the final result.

Let us say that you have a stream of data that covers the whole of byte 0 and the first 4 bits of byte 1, then the values for the maths would need to be created with a bit-mask, call it B1BM. This bit-mask should be 15 (Byte 1 bits 0 to 3). So, create an output using a bit-mask of 15 and CAN Byte 0 as the input.

Output = (256 * B1BM) + Byte 0

Now to process data that consists of the last 4 bits (MSB) of byte 1 and all of byte 2. For this output, the MSbyte is on byte 2, the LSBits are on the upper 4 bits of byte 1, so we need to create an output (let's call it B2BM) which combines byte 2 as the input and a bit-mask of 240. This is a little bit more complex to set up, because we need to divide the LSB by 16 (so it is in the range 0..15) but the MSB only needs to be multiplied by 16 (not 256) since it starts at bit 4. Thus the maths for this output is:-

Output = (Byte 2 * 16) + (B2BM / 16)

I hope that I've typed that correctly and I am sure that someone will tell me if my logic is impaired (Friday afternoon!)!

HTH
RickS