Trane Tracer AH540 Setup And Operation page 72

Chapter 4 Sequence of operation
62
of DX cooling the binary outputs are assigned as follows where the num-
ber of electric heat stages plus the number of DX cooling stages cannot
exceed four outputs.
BO3: DX cooling stage 1 or Electric heat stage 4
•
• BO4: DX cooling stage 2 or Electric heat stage 3
• BO5: DX cooling stage 3 or Electric heat stage 2
BO6: DX cooling stage 4 or Electric heat stage 1
•
Staged electric heat using a sequencer
Analog output AO3 can be configured to control an electric heat
sequencer. This option fixes the AO3 output configuration at 0–10 Vdc,
normally closed. The sequencer discrete binary outputs control the elec-
tric heat stages. The AO3 signal will step according to the configured
sequencer control thresholds, the number of stages installed, and to the
number of stages to be energized. See Table 30 on page 74.
For example, if the controller is configured for electric heat sequencer and
six heat stages, connect the step controller to analog output AO3 accord-
ing to device-specific wiring instructions.
For this example, configure the Tracer AH540/541 controller as follows:
AO3: Electric Heat (Sequencer)
•
Number of electric heat stages: 6
•
Electric heat sequencer control: default values (see Table 30 on
•
page 74)
Care should be taken to match the sequencer characteristics to the Tracer
AH540/541 configuration. The controller will step AO3 according to the
defined configuration. Figure 12 illustrates the default operation for a
six-stage electric heat sequencer configuration. Table 24 on page 63
shows staging characteristics for a common, off-the-shelf, sequencer with
one to six stages. According to the table, the sequencer requires a mini-
mum input of 5.21 Vdc to turn On the third stage. Analog output AO3 will
output 6 Vdc to energize the third stage of the sequencer, default configu-
ration.
CNT-SVX05B-EN