Applications Guide Tracer Graphical Programming - Trane

®
Summary-question answers
closed position and as a result, the calculated offset value is based on
the occupied setpoints.
The Occupancy and De-Enumerator block combination appears again
in the fan control program (Figure 134 on page 156). The fan is
requested to start in any occupancy mode with the exception of unoccupied
mode.
The last piece of the puzzle answers the following question: How does
the Occupancy block know to indicate occupied bypass mode? For the
controller to sense that it must enter occupied bypass mode, a universal
input configured as a thermistor (zone sensor) must be selected as
the timed override input in the Schedule application. See Figure 197
on page 241.
3. The network variable input providing a temperature may be checked
for an invalid value using the Fail block (Figure 198).
Figure 198: Checking a network variable input for valid data
In some cases, a Fail block may be used to check the network variable
inputs for invalid data. Table 33 shows the network variable types
(SNVTs) that the Fail block checks for invalid data. You see the hexadecimal
invalid values when setting up custom bindings in the Rover
service tool, and you see the decimal values when debugging graphical
programs in the TGP editor.
Table 33: Network variable input (nvi) and network configuration input
(nci) invalid values
SNVT
Hexadecimal
Invalid state
Decimal
SNVT_flow 0xFFFF 65535
SNVT_hvac_emerg 0xFF 255
SNVT_hvac_mode 0xFF 255
SNVT_hvac_overid 0xFF 255
SNVT_hvac_status 0xFF 255
SNVT_lev_percent 0x7FFF 32767
SNVT_occupancy 0xFF 255
SNVT_press_p 0x7FFF 32767
SNVT_switch 0xFF 255
SNVT_temp_p 0x7FFF 327.67
Note: The hexadecimal invalid values appear when setting up custom
bindings in the Rover service tool. The decimal values appear when
debugging graphical programs in the TGP editor.
242 CNT-APG001-EN