TMC222-SI TRINAMIC, TMC222-SI Datasheet - Page 14

• Manufacturer Part Number: TMC222-SI
• Description: IC, MOTOR CTRL/DRVR, STEPPER, SOIC-20
• Manufacturer: TRINAMIC

Specifications of TMC222-SI

• Motor Type: Stepper
• No. Of Outputs: 4
• Output Current: 800mA
• Supply Voltage Range: 8V To 29V
• Driver Case Style: SOIC
• No. Of Pins: 20
• Operating Temperature Range: -40°C To +125°C
• Device Type: Motor
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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TMC222 DATASHEET (V. 1.06 / March 15, 2007)
5.1.11 Reference Search / Position initialization
A stepper motor does not provide information about the actual position of the motor. Therefore it is
recommended to perform a reference drive after power-up or if a motor shutdown happened in case
of a problem. The RunInit command initiates the reference search. The RunInit command consists of
a Vmin and Vmax parameter and also position information about the end of first and second motion
(6.8.8 RunInit).
A reference drive consists of two motions (Figure 6: RunInit): The first motion is to drive the motor
into a stall position or a reference switch. The first motion is performed under compliance of the
selected Vmax and Vmin parameter and the acceleration parameter specified in the RAM. The
second motion has got a rectangular shape, without a acceleration phase and is to drive the motor out
of the stall position or slowly towards the stall position again to compensate for the bouncing of the
faster first motion to stop as close to the stall position as possible. The maximum velocity of the
second motion equals to Vmin. The positions of Pos1 and Pos2 can be chosen freely (Pos1 > Pos2 or
Pos1 < Pos2). After the second motion the actual position register is set to zero. Finally, the secure
position will be traveled to if it is enabled (different from the most negative decimal value of –1024).
Once the RunInit command is started it can not be interrupted by any other command except a
condition occurs which leads to a motor shutdown (See 5.1.10 Motor Shutdown Management) or a
HardStop command is received. Furthermore the master has to ensure that the target position of the
first motion is not equal to the actual position of the stepper motor and that the target positions of the
first and the second motion are not equal. This is very important otherwise the circuit goes into a
deadlock state. Once the circuit finds itself in a deadlock state only a HardStop command followed by
a GetFullStatus1 command will cause the circuit to leave the deadlock state.
Velocity V
[FS/s]
nd
2
Motion
st
1
Motion
V
max
V
min
Position X
Pos1
Pos2
[FS]
Figure 6: RunInit
Copyright © 2004-2007 TRINAMIC Motion Control GmbH & Co. KG