Sequence Of Operations/Scc Mode; Power-Up Sequence; Zone Temperature Control; Occupancy Modes - Trane Tracer MP501 Installation, Operation And Maintenance Manual

Sequence of Operations/SCC Mode

A MP501 controller in Space Comfort Controller (SCC) mode will operate to maintain the zone
temperature setpoint. This section provides information about the operational sequences used by
the controller to accomplish this goal.

Power-up Sequence

When 24 Vac power is initially applied to the MP501, the following sequence occurs:
1. The Status LED goes on.
2. All the outputs are turned off.
3. The controller reads all the inputs to determine their initial values.
4. A user-adjustable (Power Up Control Wait) delay timer begins. If set to less than 10 seconds,
5. The Status LED goes off.
6. The delay timer expires.
7. The Status LED goes on.
8. If a hardwired space temperature sensor is not detected and no value has been communicated,
9. Normal operation begins if no diagnostics have been generated.

Zone Temperature Control

The proportional, integral, derivative (PID) control loop in the MP501 calculates the required
heating or cooling capacity (0–100%). The PID calculation compares the measured space
temperature to its active setpoint. Refer to the sections,
Control," p.
determines the active setpoint.

Occupancy Modes

Occupancy modes can be controlled by any of the following:
•
•
•
•
A communicated request, either from a BAS or a peer controller, takes precedence over local
requests. If a communicated occupancy request has been established and is no longer present, the
MP501 reverts to the default (occupied) occupancy mode after 15 minutes (if no hardwired
occupancy request exists).
The MP501 has the following occupancy mode options:
•
•
•
CNT-SVX08F-EN
a 10-second wait will be applied.
the actuator output will override to closed and a Space Temperature Failure diagnostic will
be generated.
29. The current operating mode, consisting of occupancy mode and heat/cool mode,
The state of the local (hardwired) occupancy binary input BI1
A timed override request from a Trane zone sensor (refer to the section,
Control," p. 20)
A communicated signal from a peer device (refer to the section,
p. 22)
A communicated signal from a BAS
Occupied
Unoccupied
Occupied standby
Sequence of Operations/SCC Mode
"PID Calculations," p. 31
"Timed Override
"Peer-to-peer Data Sharing,"
and "PID
19