Skip to content

WaveSculptor200 Motor Drive Motor Sense Comms Spec

This document describes the specification for serial comms between a motor position / temperature sense adapter board and a WaveSculptor motor controller. The two communicate via a unidirectional, isolated, differential serial channel.


The serial link runs using asynchronous UART comms at 470.6 kbits/sec, 1 start bit, 8 bits data, 1 stop bit, no parity. Complete packets are sent at a rate that will keep the serial channel full.

There should be a break character inserted after each packet, to allow the receiver to resynchronize to the correct start bit if noise corrupts the transmission during a packet.

The WaveSculptor should run a timeout check on incoming comms, and flag a fault if no data is received within a certain time window (MOT error).

Packet Format

Each packet consists of four bytes. The 1st and 2nd indicate the start of packet, and either temperature or device type. The 3rd and 4th bytes indicate position or velocity data, with the type determined by the device type designation.

Data should be left-justified, and zero-padded on the right if necessary.

Temperature readings should be sent as unsigned data from the A/D converter, not converted to °C. Any linearisation, calibration, and scaling shall be performed on the WaveSculptor, using data from the Windows config software.

First Byte

Bits Parameter
7 1 = Start of four-byte packet
6 0 = Following bits are a device type
1 = Following bits are temperature
5-0 Device type, or Temperature MSB

Second Byte

Bits Parameter
7 0 = Not start of packet
6-0 Reserved if Device type, or Temperature LSB

Third Byte

Bits Parameter
7 0 = Not start of packet
6-0 Position/Velocity MSB

Fourth Byte

Bits Parameter
7 0 = Not start of packet
6-0 Position/Velocity MSB

Device Type

The device type is indicated with a 6-bit integer number corresponding to the motor adapter hardware and the specific sensors attached to it. A motor controller receiving a device type that it does not know about should flag a fault and request a firmware update.

Device types are assigned as follows:

Code Timer Inputs Motor Sensor Temperature Sensor Hardware
0 Invalid, flag a fault - - -
1 120° Halls Not Used NTC thermistor TRI74-46
2 Quadrature Encoder Not Used NTC thermistor TRI74-44
3 Quadrature Encoder Resolver, 14 bits Pt100 TRI74-45
4 Quadrature Encoder 120° halls, Timken M15, 3 bits Pt100 TRI74-50
5 Quadrature Encoder Absolute position, 12 bits Pt100 TRI74-52
6 Quadrature Encoder Not Used NTC thermistor TRI74-46
7 Quadrature Encoder Resolver, 14 bits NTC thermistor TRI74-45
8 Quadrature Encoder Not Used Pt100 TRI74-46