29144 Parallax Inc, 29144 Datasheet - Page 2

• Manufacturer Part Number: 29144
• Description: MODULE HB-25 MOTOR CONTROLLER
• Manufacturer: Parallax Inc

Specifications of 29144

• Motor Type: DC
• Number Of Motors: 1
• Voltage - Output: 16V
• Voltage - Logic Supply: 6 V ~ 16 V
• Current - Output: 25A
• Termination Style: Screw Terminal
• Product: Microcontroller Accessories
• Flash: 512 KBytes
• Operating Supply Voltage: 6 to 16 V
• Board Size: 53.34 mm x 30.48 mm x 15.75 mm
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• For Use With: 27971 - KIT MOTOR MNT/WHEEL W/POS CONT
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Modes of Operation
The HB-25 connects to the microcontroller much like a servo. You can use an extension cable (such as
Parallax part #805-00012) or a custom cable to connect the HB-25 to your controller. Reversing the M1
and M2 connections to the motor effectively reverses the direction. The HB-25 has two modes of
operation which are selected by the jumper labeled “J”.
Mode 1 is Single Mode, where only one HB-25 is present on the microcontroller I/O line. In this mode,
the HB-25 can be controlled with as little as a single pulse from your microcontroller.
Mode 2 is dual-mode, which is used when connecting a second HB-25 to a first HB-25, rather than
connecting directly to the microcontroller. This powerful feature allows two HB-25’s to be independently
controlled through the same I/O line, saving I/O pins. Two HB-25’s are required to use Mode 2.
Mode 1
Mode 1 is selected when the jumper labeled “J” is in place.
Figure 1: Single Mode Selection
Mode 1 Communication
In this mode, a single pulse value sent to the HB-25 can control the HB-25; no “refreshing” is necessary,
as is the case with a servo. For compatibility however, you may send the HB-25 pulses every 20 ms just
like a servo and it will function the same.
There is a hold-off time of 5 ms where the HB-25 will ignore incoming pulses. As a result, the unit should
not be refreshed more frequently than about 5.25 ms + pulse time. Pulse time can be anywhere from
0.8 ms to 2.2 ms. If the HB-25 receives a pulse outside of this range, it will temporarily shut off the
motor until it receives a valid pulse.
Figure 2: Single Mode Communication
The maximum time between pulses is unlimited, since a single pulse is all that is required to set the unit
running indefinitely. This is especially nice for BASIC Stamp users with complex sensor code which may
not have had sufficient time to refresh servos during the main loop. You only need to send a new pulse
when you are ready to change the speed of the motor (or stop it).
© Parallax, Inc. • HB-25 Motor Controller (#29144) • v1.2 4/07
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