User Manual

Trapezoidal Switching
Advanced Digital Motor Controller User Manual 99
erence section). Note that in the case where digital inputs are configured as Hall inputs,
pull-up resistor from the input pin to the +5V must be added externally. Use 4.7K resistors
wired as shown in Figure 8.3.
Important Warning
Keep the Hall sensor wires away from the motor wires. High power PWM switching
on the motor leads will induce spikes on the Hall sensor wires if located too close.
On hub motors where the Hall sensor wires are inside the same cable as the motor
power wires, separate the two sets of wires the nearest from the motor as possible.
Important Notice
Make sure that the motor sensors have a digital output with the signal either at 0
or at 1. Sensors that output are gradually changing are typically analog signals will
cause the motor to run imperfectly.
Hall Sensor Verification
Hall Sensor miswiring is a very common cause when the motor is not running. You can
send the following query to verify that the hall sensors are seen by the controller:
?HS [channel]
The reply is one or two numbers, depending on the number of channels, of values be-
tween 0 and 7 with each bit representing the state of each of the HA, HB and HC sen-
sors.
Turn the motor slowly by hand while sending frequent ?HS queries. Verify that all valid
combinations appear at one time or the other and that none of the invalid combination
ever show.
For 120 degrees spaced sensors, 1-2-3-4-5-6 are valid combinations, while 0 and 7 are
invalid combinations. For 60 degrees spaced Hall sensors, 0-1-3-4-6-7 are valid combina-
tions, while 2 and 5 are invalid combinations.
Note that HS query does not work on the first generation HBL and VBL family of products.
Hall Sensor Wiring Order
The order of the Hall sensors and these of the motor connections must match in order for
the motor to spin. Unfortunately, there is no standard naming and ordering convention for
brushless motors.
The Hall Sensor and Motor Phases naming convention used in Roboteq controllers is A,
B and C for the sensors and U, V and W for the motor phases. When rotating the motor
shaft clockwise by hand, the controller expects the sensor A to be a mirror of the voltage
generated between wires U and W, sensor B between V and U, sensor C between W and