Rather depends what load you intend to connect. If the load is 24V and you need 2 supplies in parallel to get supply the peak current, then that is, I hope, an obvious yes.

If they are supplying a 48v load then the 2 will be in series, so the 0V of one 'sits above' the 24V of the other. (and you may or may not ish to earth the top, bottom or middle of the stack... depends on how )

IF they are supplying 24Vindependant loads, then it really depends how those loads are organised, and what you want to happen if there is a fault that connects kit  on one supply to kit on the other. Decide that behaviour and your question is answered ;-)

The power supply does not know or care if you declare either of its output terminals to be grounded, floating or connected to something else, until a circuit is completed to the other terminal that causes current to flow - what you must not do is ground both sides .

Mike.

In the general case (I'm not familiar with these specific units), be careful if the outputs are in any way connected to the supply side - e.g. if the output is referenced to supply PE or even supply N - or if the design doesn't provide galvanic isolation from the supply side, and if the two units could be supplied from different circuits. Tying potentially two different supply circuits together could have "interesting" results. Even if the 0V rails are just referenced to the incoming Earth, your link might be exposed to a portion of the a.c. earth fault currents should one of the supply circuits suffer an Earth fault, unless some precautions are taken.

   - Andy.

Sitop is a range of supplies, but as far as I know they are all floating output - it is up to the user to decide where on the secondary side to earth or not earth  ,

Where problems can also arise is with interfacing to power supply  signals or controls that indicate overloads or power on and off - especially when supplies are in series, as then the signals do not share a common reference voltage.

Mike