Chapter 4 Input/output functions and wiring for typical applications
is established and then is no longer present, the controller generates a Generic AIP Failure diagnostic.
For the CO2 measurement configuration, a 4–20 mA sensor must be hard- wired to the AI4 terminal as shown in Figure 5. The sensor will transmit a 0–2000 ppm value to the BAS. This configuration has no direct effect on Tracer ZN521 operation. If a valid value is established and then is no longer present, the controller generates a CO2 Sensor Failure diagnostic.
Figure 5. AI4 terminal wiring: CO2 measurement
Tracer ZN521
24 Vac
CO2 sensor (Trane 5010 0828 shown)
24 Vac
GND Signal
For the RH measurement configuration, either a hard-wired 4–20 mA zone humidity sensor (see Figure 6) must provide a value to the controller or a BAS communicates a value to the controller. The controller uses this value to support the dehumidification function. (For more information, see “Dehumidification” on page 47.) If a valid hard-wired or communi- cated relative humidity value is established and then is no longer present, the controller generates a Humidity Input Failure diagnostic and disables the dehumidification function.
Figure 6. AI4 terminal wiring: RH measurement
Tracer ZN521
RH sensor
