The Roland DP-2 pedal is perfectly compatible with the Roland PC-200 MkII.

1st tip: connect the MIDI Out of the PC-200 MkII to a device that displays MIDI messages (for example, a computer running a MIDI monitor program) and check if the PC-200 MkII sends CC64 message when the pedal is moved.

2nd tip: if the PC-200 MkII does not send a CC64 message when the pedal is moved, unplug the DP-2 from the PC-MkII, set a multimeter to "resistance measurement" mode and measure the DP-2 1/4" jack. If the DP-2 works well, you should measure a short circuit when the DP-2 is released, and a break when the DP-2 is pressed.

3rd tip: if the PC-200 MkII sends a CC64 message when the DP-2 pedal is moved, there is a problem with the setting of the Roland SC-88 Pro.

Thanks very much @Istvan. I will try those steps and report back.

Yes the pedal makes and breaks circuit according to multimeter.

Midi monitor on laptop shows:


2 58:28.1 out Controller Hold Pedal (on/off): 127 Chn 1 127 B0 40 7F

3 58:28.7 out Controller Hold Pedal (on/off): 0 Chn 1 0 B0 40 00

I can't find a midi monitor that shows Control Change codes, but I take it from the above that the pedal is working. I shall investigate the SC88 module (most of which is way beyond me!!).

The MIDI "HOLD pedal" message in hexadecimal is as follows:
"Bc 40 dd", where
"c": the MIDI channel (0..F),
"dd": hold pedal status. 40..7F = pressed, 00..3F = released.
If the PC-200 MkII sends "B0 40 7F" when DP-2 is pressed, and B0 40 00" when released, the PC-200 MkII and DP-2 are working fine.

Thanks for the confirmation. I shall wade through the 216 page manual for the SC88!!

In the SC-88 Pro user patches (native map and SC-88 map, variations 064 and 065) you can disable all Control Change messages or only the HOLD PEDAL message.
Although the chances are small that you are using only the user patches and receiving these messages is disabled in all user patches...

You might try resetting the SC-88 Pro's user memory:
"With the power turned on, press the INSTRUMENT< and INSTRUMENT> buttons simultaneously while holding down the SELECT button. The following display will appear: 'Init All, Sure?' If the ALL button is pressed, the factory setup will be executed." (Roland SC-88 Pro Service Notes, https://www.synthxl.com/wp-content/uploads/2020/03/Roland-SC-88-Pro-Service-Manual.pdf)

Is the SC-88 Pro memory backup battery OK? No "Battery Low" message?