Elmo HARmonica Speed, Electrical angle, Power DC voltage, Peripherals, Position decoders

Description

The full current range of the amplifier.

The amplifier represents MC Amperes by 14000 bits internally.

(The maximum A/D reading is 16384 and some spare is left for overshoots and over-current detection)

Torque command multiplier.

Internal torque command = WS[22]×DV[1].

Phase current multiplier

Internal phase current = WS[5]×Phase Current[Amp]

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The internal representation of phase currents is by A/D bits.

Torque commands, and the active and the reactive parts of the current have another representation, since the coordinate transformations from phase current to torque introduce scaling.

The relation between internal phase currents, internal torque, and Amperes is given by the following commands:

Command

MC

WS[22]

WS[5]

2.5.2 Speed:

Speeds are represented internally by the units of counts/(216 speed controller sampling times).

For example, if the sampling time of the speed controller is 200usec (5000Hz sampling

frequency), then 1000 counts/sec will be represented internally as		1000 ⋅ 216	= 13107 .
		5000Hz
The relation between speeds and internal commands is given by the following commands
Command	Description
TS	Sampling time of the current controller. The sampling time of the sped
	controller is 4×TS.
WS[53]	Conversion from internal units to counts/sec
	Speed (counts/sec) = WS[53]×Speed (Internal representation)

2.5.3 Electrical angle:

The electrical angle is measured by 1024 counts per electrical revolution.

Think of a motor with 3 pole pairs. To rotate this motor a full mechanical revolution in the stepper mode (UM=3) you have to specify the movement of (3×1024)=3072 position counts.

2.5.4 Power DC voltage

Power DC voltage is represented internally in A/D units.

The relation between the internal representation and the bus voltage is given by:

Command	Description
WS[54]	Conversion from internal units to Volts.
	Power DC voltage = WS[54]×Power DC voltage (Internal representation)

2.6 Peripherals

This section summarizes the set of Harmonica peripherals.

2.6.1 Position decoders

There are two position decoders, termed main and auxiliary. The main and the auxiliary decoders are similar. Both decoders are timed (through the timer sets A and B) for accurate speed information.

A position decoder measures quadrature or Pulse/Direction. The maximum counting rate of