Yes, you can.
To secure Heat-On to square or rectangular hotplates, use RR61087 Heat-On Adapter Plate for Square Hotplates.
It has four sliding (adjustable) jaws that enable you to fit it onto your hotplate. There is a circular protrusion on top that fits the recess in the bottom of Heat-On. This means the Heat-On block is secure and there is good heat transfer between the hotplate and the Heat-On.
RR61087 is suitable for hotplates from 140 x 140 mm to 200 x 200 mm.