TRACKMASTER
Ch. 8
Product Requirements
317-160-406 Rev 4
TMX428 TMX428CP & TMX58 Service Manual
61
May 2021
Product Requirements
FG0495 Smart Power Supply
INTRODUCTION
The TMX428, TMX428CP Universal Power Supply (UPS) treadmill control provides a means of
controlling belt speed and elevation for the treadmill through the use of either an RS-232 serial port or
USB port. The communication protocol is based on the industry standard. In addition to the physical
interfaces with the controlling system (PC), the motor controller and elevation motor, the UPS also
includes an interface to an emergency stop switch and an SD card. The UPS supplies interfaces with
a console, a soft stop switch, an output expansion port, and a low voltage fan that will not be covered
in this document.
SCOPE
This document only applies to the electronic control for the TMX428 & TMX428CP. Specifications
for the mechanical treadmill, elevation motor assembly, belt motor and motor controller are not
covered in this document.
OPERATIONAL OVERVIEW
When power is applied to the unit, the UPS reads the contents of the non-volatile memory and
verifies the calibration contents with a checksum. If the contents are not valid, the calibration
constants are set to non-operational values and the unit is put into a state where operation is
suspended pending re-calibration.
If the contents are valid, the unit enters a startup mode where the system checks to see if it should
enter Self-test mode (described in the
MODE section) and begins to find the zero elevation
point by turning on the elevation motor in the down direction. If motion is not detected for two
seconds, the system assumes that the lower elevation limit has been reached. During the “elevation
zeroing” ti
me, if a command to start the belt is received from the PC, it is assumed that the PC is not
aware of the UPS power cycle and the unit will enter a non-responsive state (waiting for either a
communication timeout or a stop command). If the elevation limit is found without receiving a start
belt command, the UPS enters the operational mode with a set speed and set elevation of zero.
In operational mode, the unit continuously controls the belt speed output, the belt enable output, and
the outputs to raise or lower the elevation based on the current set points for speed and elevation.
Through the use of either communication port, the unit accepts commands to modify the belt state,
the belt speed, and the deck elevation. The current state of the control may also be queried through
the use of this serial port. As commands are received to change the set point speed or set point grade,
they are checked for format and range. Pending approval, the new set points are adopted and
adjustments are made to the state of the outputs.
Speed control is done in a closed loop that monitors the belt speed using two different speed
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