VEMS EGT & WB lambda signals from ECU: RS232 signal splitting

[Bram]

Guys,

I would like to have my laptop and VEMS round gauge connected to the ECU in parallel.
In short; I want to keep track on EGT and lambda values during mapping/driving by watching the big numbers in the VEMS round gauge (easier to watch while driving), while at the same time log the VEMS data on the laptop. This would allow me to do mapping on my own.

Can I use this kind of RS232 splitter to make that work?

http://www.compuphase.com/electronics/rs232split.htm

[Bram]

Or something like this: http://www.sfcable.com/cable/p/D920-YY.html

[Nuvo]

Bram, I think you need something a little more sophisticated than the above cables.

This software serial port splitter would probably work although I have no experience of using it myself. Of course, there may be other solutions out there.

Download a copy from here and report your findings. You have a 15 day trial to evaluate the software and its suitability. I would be interested to hear how you get on with it.

Update:
Just ignore my post, I don't think it would help solve the problem you describe.
I reread your post and see that you want to share an ECU port rather than a PC port with other devices.

[A80Avant]

Bram, noone has ever tried these with VEMS so you would be the first to tell us if it works or not.

For me, using the multidisplay screen, works fine and i only connect the laptop on the RS232 to datalog,therefore i have everything in front of me.

Even if you have a big dial in front of you, when you are tuning high revs and high speed, it is difficult to see what is happening, hence the reason for datalogging. you see those things afterwards.

Idealy you could do what Jamo is planning(and maybe me in the future) and get a in car pc to have VEMS on a 7inch touch screen on there all the time.

[Bram]

Hi Nuvo,

mmmm, I am not sure if this will work for me, as I have only 1 RS232 port on my laptop and I need hardware duplication of the RS232 signal coming from the ECU.I need a real connector splitter so to say.

Another option maybe could be that I get the ECU serial signals in via RS232 like I have today, and use a USB-> RS232 convertor on my laptop to forward the serial ECU data to the VEMS round gauge using your RS232 duplicator software.

I will give that a try once I get the VEMS round connected in the coming weeks.

[Nuvo]

Okay, I think I have a better understanding of what want to achieve.

The laptop and the ECU will be using bi-directional data transfers.
I'm not sure if the VEMS round gauge makes use of bi-directional or uni-directional a transfers.

Either way, I think you would need some sort of hardware device that performs automatic switching between the Laptop and VEMS gauge. It would need a buffer so that no data is lost when switching between devices. i.e., an 'intelligent splitter' is what would be needed.

I've had a quick search on the web for a suitable device and so far nothing grabs my attention. If I find anything I'll post it up for you to take a look at.

[a4kquattro]

Hi Bram,

you can use a "dumb" splitter if you want, just be aware that you CANNOT have both connected at the same time, so that doesn't sound very useful...

[Jamo]

I have dual rs232 ports on my VEMS one for the laptop connection and the other one for the LCD output I think

It's an option on the new ecu's I wonder if it could do what you describe above?

[A80Avant]

One of the rs232 is for the LCD screen as mentioned.

i dont know if it can be used with the gauge.

Bram, you should have both of them. You bought the ECU later than me from Marc, and i have it as well

[Bram]

mmmm, interesting. It seems I have been too early with my VEMS purchase then

Do you have a picture of your VEMS box Jamo, so I can compare?

[a4kquattro]

mmmm, interesting. It seems I have been too early with my VEMS purchase then

Do you have a picture of your VEMS box Jamo, so I can compare?

eh? You have the same dual rs232 connections. I have no doubt that Jamo's ECU is setup the same as yours in terms of hardware. They are for different functions, one is exclusively for the lcd, the other is for serial communication with the ecu, and also for communication with the gauge, but not both at the same time (the lcd can run at the same time as a pc but the pc cannot be connected to the ecu at the same time as vems round).

[A80Avant]

On a slighlty similar note, marc, does the lcd work with the 1.1.6x versions?

[a4kquattro]

On a slighlty similar note, marc, does the lcd work with the 1.1.6x versions?

yes, although I have not personally verified that.

[Jamo]

It does yes

[Bram]

eh? You have the same dual rs232 connections. I have no doubt that Jamo's ECU is setup the same as yours in terms of hardware. They are for different functions, one is exclusively for the lcd, the other is for serial communication with the ecu, and also for communication with the gauge, but not both at the same time (the lcd can run at the same time as a pc but the pc cannot be connected to the ecu at the same time as vems round).

Aha, so all VEMS ECUs do have just one RS232 connector as I hoped. I though Jamo had a special version, since he spoke about 2 RS232 ports on his ECU.

Is there a feature in Megatune of VEMStune then to set alarms (or to magnify certain PC gauges on the screen) if a certain value is reached so I can really read it while tuning on my own?
I need something that warns me or shows me the EGT and lambda values while driving, but since I will be wearing headphones to listen for knock and need to keep an eye on the street when going fast. I need a visual feedback that is easy to check all the time.