Can the TMC4361 operate in Circular Motion Mode while using PID Regulation?

Can the TMC4361 operate in Circular Motion Mode while using PID Regulation? No, Circular Motion Mode is not compatible with PID Regulation. If closed-loop circular motion is desired, it is recommended to to utilize Closed-Loop operation (ENC_IN_CONF.regulation_modus = 0x1) rather than PID Regulation (ENC_IN_CONF.regulation_modus = 0x2 or 0x3).

Can the TMC4361 Eval kit be connected to TMC5160/5130 Eval kit

TMC5160/5130 is a cdriver IC, it has a controller and driver embedded on the common base. The evaluation kits are mainly designed to explore the controller features present in the IC itself. TMC4361 is the controller IC that is intended to take action on the step loss of the motor as it has a PID controller in the feedback. Therefore, it is not possible to connect two controller eval-kits. Instead we recommend using the TMC4361 with a gate driver IC, so there is only one controller IC in the loop. An example of such a setup would be to use TMC2160 gate driver IC in combination with TMC4361.

Should I use SPI output or Step/DIR output when using the TMC4361A with the TMC2130/2160?

It is recommended to operate in S/D mode with the TMC2130 and TMC2160. You can still send SPI datagrams to the driver IC to configure settings, etc, but motion will be controlled via Step/DIR interface.

Should I use SPI output or Step/DIR output when using the TMC4361A in closed loop?

We recommend using Step/DIR output when operating in closed loop. In this mode, you will still be able to send SPI commands to the driver, but the STEP/DIR signals will be controlling the motor movement.

How do I convert HEX to real world velocity units on the TMC4361A?

The units of the velocity registers are in a unit of pps (pulse per second). This is equivalent to microsteps/second. If you are operating with 256 microsteps per fullstep, and 200 fullsteps / revolution, 51200pps would be equivalent to 1 revolution per second (256 uSteps * 200 FullSteps = 51200 uSteps per rotation). Converting this value to hex depends on the velocity register being written to, as they have different bit lengths and formats. VACTUAL is a 32 bit signed value with no decimal places. This value uses 2's compliment for negative numbers. The MSB is the sign bit. VSTART, VSTOP , and VBREAK are all unsigned 31 bit values; 23 bits for the integer portion, and 8bits for the decimal place. the 23 MSBs use a normal hex to dec conversion for the integer portion. The 8 LSBs represent the decimal portion of this value. This is computed as a fraction of fullscale. To put it mathematically: Hex2Dec(HEX_VALUE) / Hex2Dec(0xFF) = Fractional_value VMAX is signed 32 bit. The 24 MSBs represent the integer portion in 2s complement, and the 8 LSBs represent the fractional decimal place. Again, the fraction is computed as a fraction of full scale (See Equation Above). For the fractional registers, VSTART, VSTOP, VBREAK, and VMAX, an easy way to compute your hex value is to multiply your desired value by 256 and then convert to hex. This will account for the decimal place. As an example, if I am set to 256 microsteps and have a 1.8deg motor (200 fullsteps per rotation), and I want the motor to spin at 100 rpm, I would do the following conversion: (100 rev/minute) / (60 seconds/minute) = 1.66667 rev/second 1.66667 rev/second * 200 Fullstep/rev = 333.333 fullsteps/second 333.333 fullsteps/second * 256 uStep/Fullstep = 85333.3333 pps Now to convert 85333.333 to Hex: Multiply by 256: 85333.333 * 256 = 21845333.33 Remove the remaining decimal places. These cannot be represented by an 8 bit decimal place. Convert to hex: Dec2Hex(21845333) = 0x014D5555 We can check this value by separating into integer and decimal portions. Integer portion should equal 85333, and decimal portion should be approximately 0.333 (there will be some rounding error): Integer: Hex2Dec(0x014D55) = 85333 Decimal: Hex2Dec(0x55) / Hex2Dec(0xFF) = 85 / 255 = .33333 We can see that multiplying by 256 and then converting to hex is a quick and valid way to convert these fractional velocity values into hex. As an alternative, we provide a Calculation Excel Document that is helpful for converting Velocity to hex, as well as acceleration values, and ramp parameters.

Can Trinamic controllers handle encoders that output absolute coordinates? Which types, protocols are supported?

The only controller we currently have that accepts signals from absolute encoders is the TMC4361A . It can accept either SPI or SSI encoder interface signals, as well as ABN incremental encoders. We also have a module (controller + driver on a pre-made PCB) that can interface with an analog, digital hall, SPI or SSI encoder. Please take a look at the TMCM-1636 as well.

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