User's Guide _______________________________________________________________________ 
6  ____________________________________________________________________ M211659EN-C 
List of Tables 
Table 1  Manual Revisions ....................................................................... 8 
Table 2  Related Manuals ......................................................................... 8 
Table 3  Applicable Patents .................................................................... 10 
Table 4  GMW90 Series Transmitters .................................................... 13 
Table 5  Parameters Supported by GMW90 Series ............................... 14 
Table 6  Serial Interface Settings ........................................................... 35 
Table 7  Basic Serial Commands ........................................................... 37 
Table 8  Advanced Serial Commands .................................................... 37 
Table 9  FORM Command Parameters .................................................. 51 
Table 10  FORM Command Modifiers ...................................................... 51 
Table 11  Effect of Elevation on CO
2
 Measurement ................................. 65 
Table 12  Troubleshooting Table .............................................................. 73 
Table 13  Error Messages ........................................................................ 74 
Table 14  Performance ............................................................................. 80 
Table 15  Operating Environment ............................................................. 81 
Table 16  Inputs and Outputs ................................................................... 81 
Table 17  Mechanics ................................................................................. 81 
Table 18  GMW90 Series Spare Parts and Accessories .......................... 82 
Table 19  Device Object Properties .......................................................... 87 
Table 20  Carbon Dioxide Object Properties ............................................ 89 
Table 21  Status Flags .............................................................................. 89 
Table 22  Reliability .................................................................................. 89 
Table 23  Event State ............................................................................... 89 
Table 24  Temperature Object Properties ................................................ 90 
Table 25  Status Flags .............................................................................. 90 
Table 26  Reliability .................................................................................. 90 
Table 27  Event State ............................................................................... 90 
Table 28  Relative Humidity Object Properties ......................................... 91 
Table 29  Status Flags .............................................................................. 91 
Table 30  Reliability .................................................................................. 91 
Table 31  Event State ............................................................................... 91 
Table 32  Calculated Humidity Objects .................................................... 92 
Table 33  Calculated Humidity Object Properties ..................................... 92 
Table 34  Status Flags .............................................................................. 92 
Table 35  Reliability .................................................................................. 93 
Table 36  Event State ............................................................................... 93 
Table 37  Operation Pressure Object Properties ..................................... 93 
Table 38  Status Flags .............................................................................. 93 
Table 39  Operation Altitude Object Parameters ...................................... 94 
Table 40  Status Flags .............................................................................. 94 
Table 41  BACnet Smart Sensor BIBBs Support...................................... 95 
Table 42  BACnet Standard Application Services Support ...................... 96 
Table 43  Modbus Functions Supported by GMW90 ............................... 97 
Table 44  GMW90 Modbus Measurement Data Registers ....................... 97 
Table 45  GMW90 Modbus Status Registers (Read-only) ....................... 98 
Table 46  GMW90 Modbus Error Code Bits ............................................. 98 
Table 47  GMW90 Modbus Configuration Parameter Registers .............. 98 
Table 48  GMW90 Modbus Device Identification ..................................... 99 
Table 49  GMW90 Modbus Exception Responses ................................... 99