Xbee Rx Response and TX differents

Dear Friends,
In this opportunity despite of the “xbee pro s2b” (XBP24B7PIT) modules can communicate each other, the Rx value (0 - 1023) is different from the Tx analog value, additionally, the Rx value does not change although the Tx value changes.
Both modules are configured in API 2 (one as coordinator and the other as end device), have the same PAN ID, and so forth.
In order to reach this purpose I am using arduino boards UNO R3, xbee shields of DFRobot v1.4, and a Seeedstudio relay shield.
The main purpose of the sketch is to control a relay if the analog value is in between a definite range, but by the moment I am trying to visualize the Rx value in the monitor to confirm the that Tx and Rx will be the same.
Sincerely I appreciate very much your help.
Thanks in advance.

If I understand what you are saying, what is VREF connected to?

Hi mvut,
Thanks you very much. I am supplying 5v through arduino’s usb connector to power xbee module and devices. Additionally, the sensor value is 0-1023 or 0-5v.