The plates installed into an RV tank don't output anything themselves. They need an external device that measures the capacitance between those plates. The EMS-D10 requires a sender that output a voltage between 0-5V.
Princeton Electronics is the only company we know of that makes capacitive senders with this sort of output. Their full capacitive probe systems can be bought from Aircraft Spruce. If you have installed the Vans plates into the tank that do not have any electronics connected to them, you will need something that converts the capacitance measured across those plates to voltage. We have heard that Princeton Electronics may make a converter that does this conversion too. Here is their direct contact information:
Todd Stehouwer
Princeton Electronics, Inc.
616 243-8800
todds@princeton-electronics.com