I am not sure what Labview and the USB 6343 DAQ bring to the party here. Why can you not control the EasyHeat diractly from the analog output of the Omron unit? That would be your level 1 control. Set the temperature setpoint on the Omron and let it measure the tempertuure of the worpiece with your Pt100 sensor and issue a power demand analog signal to the EasyHeat.
You can use the NI kit to add a level 2 supervisor that monitors & records the temperature, power demand & workpiece temperature etc. As both the Omron & Easyheat have serial communications, it can control them too. I have only scanned the manual, but the Omron seems to lack Process Variable (PV) re-tranmsmit and remote set-point input with Pt100 sensor type, so if you wan to do temperature scheduling & PV monitoring you may have to use the serial comms to do this.
I strongly reccomend that you have some kind of independant overtemperature system that detects the workpiece getting too hot and cuts off the power to the heater. This is because if your Pt100 sensor becomes loose, it will become colder than the workpiece. the Omron will view this as the workpiece being too cold, so will increase temperature. This could lead to runaway heating.
