Temp Sysex Message

Question

Hi I'm trying to get  MD to send sysex for controlling tempo
The minimum on the dial on my instrument is 40 and  the maximum is 240
I've  been trying for a few days to sort this out but I'm not having  any joy.
I got a reply from a Facebook post on the midi designer group to say put a V in the  sysex message. The tempo does change but its all over the place so im not sure where Im going wrong
On the message it says TL & TH which I presume is tempo low and  tempo high .
Ive placed a V in the message and selected 2 bytes
When I try the dial as mentioned it does change but the tempo isn't  correct and 50 bpm sounds more like 200 if that makes  sense
Any help would be appreciated
Antonio

Images

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Comments

“ I've  been trying for a few days to sort this out but I'm not having  any joy.”

What did you try? Try one byte two byte lsb first etc and record your findings. Unless somebody knows more than you do, which is possible, trial and error will get you there

If you take notes it’s science. If you don’t it’s trying random stuff ;)

Answer 1

Here is the answer I posted for you on FB, didn’t realize you asked both places.  If any follow up, let’s keep it here.

 The MDP2 format for the sysex message would be "43 70 70 40 50 V"  - then select "2" for bytes in value.

Next question would be how it is scaled.  You can start by selecting Midi min of 40 and max of 240.  (You have to set 2 bytes in value first or midi max value will be limited to 127).

If that doesn't work, a few other ways to suss out the coding:
- if tempo goes from 40.0 to 240.0, try 400 min, 2400 max
- if the board will transmit the sysex, turn on log and watch what the min/max values transmitted are, and how they follow the tempo control
- total brute force - choose 0 min 16383 as max, and scan through to see where tempo tracks the mdp2 control.  Maybe divide into 1000k chunks rather than trying the entire range at once.

You didn't include the board specifics so I could do more research, but looks like a Yamaha from the 43 code.  Since mfrs often stick to a common format, you might find a similar mfr layout where the tempo format is decoded.

Comments

Hi again  , I've had a day or two to try a few things out and tried the instruction above
I'm getting tempo control now but again its not matching up with the correct tempo as I move the dial or a slider
Ive also put a couple of momentary buttons on so I can step up and down to make it easier for me to monitor what is going on
A couple of questions if you don't mind
I have put the number of ticks set to 200 , I notice that 140 on the dial or slider is missing so it jumps from 139 to 141 so I've set it to 201 and its showing now ,
Im not able to set the tempo to 400 to 2400 as it wont go as high
Does the default  value need to be set 16383 (100% 240) ?
Thankyou

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So midi min of 20 and max of 240 worked?  Maybe all you need to do is set display min and max to match.

Default value should be your most used tempo.

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Ive tested 40 min and 240 max with just two ticks just to try  it out so I'm getting the tempo as real time tempo with those 2  , its all the other messages in between ( 41 and 239) . Im finding as I go up in steps of one that for example,  a tempo of 70 is faster than tempo of 100.  I've matched the display min to 40 and max 240 yes
I'm half way there and I'm getting different tempos as I turn the dial but just not the correct tempo ,  I'll keep trying different settings thanks

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Ugh, I just noticed that this format appears to have LSB first.  I should have noticed this on first look, but I have never encountered it in my boards.  Try pressing the LSB First button next to bytes in value.

Answer 2

Here is the answer I posted for you on FB, didn’t realize you asked both places.  If any follow up, let’s keep it here.

 The MDP2 format for the sysex message would be "43 70 70 40 50 V"  - then select "2" for bytes in value.

Next question would be how it is scaled.  You can start by selecting Midi min of 40 and max of 240.  (You have to set 2 bytes in value first or midi max value will be limited to 127).

If that doesn't work, a few other ways to suss out the coding:
- if tempo goes from 40.0 to 240.0, try 400 min, 2400 max
- if the board will transmit the sysex, turn on log and watch what the min/max values transmitted are, and how they follow the tempo control
- total brute force - choose 0 min 16383 as max, and scan through to see where tempo tracks the mdp2 control.  Maybe divide into 1000k chunks rather than trying the entire range at once.

You didn't include the board specifics so I could do more research, but looks like a Yamaha from the 43 code.  Since mfrs often stick to a common format, you might find a similar mfr layout where the tempo format is decoded.