I am the author of CicloTour and unfortunately I cannot speak the Dutch language (sorry for writing in english therefore). I've just seeing the Hac4000 request by chance.
If this post violates the forum rules (advertising for example), please delete it -> I just remember the old days, when the Hac4 devices were state of the art and I am impressed in some way that some of these devices are still being used, yo maybe I'm able to help a little bit.
Are you using the latest CicloTour version (this should be a version >= 4.30). If you're using a Hac4Pro (4000) I assume, that the Hac4000 interface is a 'newer' USB based interface. The very old serial interfaces propably won't work with current Windows OS, but the USB based interfaces should work and at the CicloTour preferences dialog it's best to choose the USB1 Device (and not a COM-Port), because then the device will be adressed by the driver as a native USB device.
It's
important that the download dialog will show a
Pro/4000 Mode string in the caption bar of the download dialog, otherwise the download will not work with this device type, cause every HAC type has needed a special handling.
As far as I can remember there have been some
mechanical issues with older interfaces: the cap of the interface lost pressure, so that the Hac device does not contact well to the pins of the interface. A little
thin foam rubber between the interface cover and the Hac4 device was able to solve this problem.
Unfortunately the device is too old to investigate deeper, but I've done some tests some years ago when I adapt the device import routines to my TrainingLab Pro project (it's a kind of descendant of HRMProfil/CicloTour) and I was able to import some Hac4 and Pro (= 4000) devices on my current Windows 10 PC.
Due to the fact that the device importing programme code was more or less taken from the old CicloTour project, the import shoud also be possible with CicloTour under Windows 10.
Maybe this helps...
PS: I am not related to the Ciclosport company