I have a CR100 datalogger. When I connect the CS106 Barometric Pressure Sensor, instead of reading 980 mb, it shows 500 mb.
Check your wiring, and make sure your data logger program is activating the switch to power up the sensor. A reading of 500mb can mean 0 volts on the analog channel.
I suggest using ShortCut to make a simple program and wiring diagram to test it.