connecting a monitor to an Atem SDI Pro Iso

I have just purchased the above. I chose the SDI version as I neeed the cable length from Camera to switcher. However the output is also SDI. I tried using a third party SDI to HDMI covertor to connect to an HDMI Acer monitor, but there is an error message that says that the input is inconpatible. Is there a Blackmagic converter that will overcome this problem, or do I have to buy an SDI monitor.
Many Thanks
Many Thanks