SNVT bindings broken after replacing a VT7600 Viconic thermostat

Issue

The SNVT bindings break after replacing a VT6700 Viconic thermostat with a VT7600r, VR76_PIR, SE7600, etc.

Product Line

TAC Vista, SmartStruxure Solution

Environment

  • LonMaker
  • NL220
  • Schneider Electric SE76XX stats

Cause

The older VT7600 Viconic thermostat includes the nvoOAT SNVT. On the newer models of the Viconic stats the nvoOAT variable is no longer available. The removal of the nvoOAT variable causes the SNVT table to become unaligned and breaks the existing bindings that had been created.

Resolution

When replacing a VT7600 thermostat with any new Viconics model the existing SNVT bindings will be broken. It is important to make note of all bindings made to the stat before performing a replace with a newer stat.