WAM Properties List

Common Properties

These properties are common to both the motor encoders and the Safety Module.

Property:	Definition:	Values (Units):	Read/Write:	Default:	Saved:	Notes:
ADDR	Address to peek/poke	R/W		0	No
ANA0, ANA1	Analog input values from the on-board DAC	0 – 4095	R/-	None	No	0-3.0 V only
BAUD	RS-232 serial baud rate	Bits/sec	R/W	9600	No
CMD	Execute a special command over CANbus, instead of the typical Get/Set command.		-/W	None	No	Set CMD to the enumerated value of the desired command. Can only be used with commands that don’t take values: RESET, HOME, KEEP, PASS, LOOP, HI, IC, IO, TC, TO, C, O, T
DEF	Default command for CAN		-/W	None	No	Resets all parameters to their defaults (use SAVE to store them permanently in EEPROM)
DIG0	Digital I/O, PWM-capable	-1 to 100	R/W	0	No	0-3.3 V only (no optical isolation, reverse voltage, or overvoltage protection, be careful). -1 = Input, 0 = Output low, 1 = Output high, 2-100 = PWM duty cycle of n%, Pin 41 (Pin 44 = GND)
DIG1	Digital I/O	-1, 0, 1	R/W	0	No	0-3.3 V only (no optical isolation, reverse voltage, or overvoltage protection, be careful). -1 = Input, 0 = Output low, 1 = Output high, Pin 43 (Pin 44 = GND)
ERROR	Reports the last error encountered by the Puck		R/-	None	No	Not yet implemented
FET0	Tensioner output (0 = Off, 1 = On)	0, 1	R/W	0	No	Pin 33 floats when FET0 = 0, it is grounded when FET0 = 1 (Pin 34 = 5V, current source)
FET1	Brake output (0 = Off, 1 = On)	0, 1	R/W	0	No	Pin 31 floats when FET1 = 0, it is grounded when FET1 = 1 (Pin 32 = 5V, current source)
FIND	Find command for CAN		-/W	None	No	Used for calibration. Set FIND to the value you want to calibrate: setProperty(0, FIND, FALSE, MOFST);
GRPA, GRPB, GRPC	The communication groups to which the puck belongs	0 to 31	R/W	None	Yes	A Puck can be addressed by ID, or as part of a group
ID	CANbus ID	0 to 31	R/W	None	Yes	Each Puck on a CANbus must have a unique ID
ILOGIC			R/-	None	No
IMOTOR			R/-	None	No
LOAD	Load a property from non-volatile memory into active puck memory via the CAN bus		-/W	None	No	Example of use: setProperty(0,4,LOAD,FALSE,MT)
LOCK	A combination lock to allow write access to locked properties		-/W	None	No	These properties are locked: ROLE, SN, PTEMP, UPSECS, OD
MODE	The control method for the motor controller	0, 2, 3, 4, 5	R/W	0	No	0 = Idle, 2 = Torque, 3 = PID, 4 = Velocity, 5 = Trapezoidal
OTEMP	Over temperature limit		R/W	82	No	MT is reduced gradually 16C before OTEMP. When TEMP >= OTEMP, MT will be zero.
PTEMP	Peak temperature recorded		R/W	None	Yes
ROLE	A value used by the firmware to determine the function of the device		R/W	None	Yes	Bitfield: F=Feedback, R=Role: XXXX FFFF XXXX RRRR ROLE: 0 = Tater, 1 = Gimbals, 2 = Safety, 3 = Wraptor, 4 = Trigger FEEDBACK: 0 = Optical encoder, 1 = Magnetic encoder
SAVE	After setting a non-volatile property, save it to non-volatile Puck™ memory		-/W	None	No	setProperty(0, 4, SAVE, FALSE, MT);
SG	Analog reading of the strain gage peripheral	0-4095	R/-	None	No	The 12-bit value 0-4095 corresponds to an analog reading of 0-3.0V
SN	The unique manufacturing serial number for this Puck		R/W		Yes
STAT	0 = Reset/Monitor, 2 = Ready/Main	0, 2	R/W		No	The Puck firmware is divided into two parts: Monitor and Main. The Puck initially boots into Monitor where there is a very limited command/property set. From here, you can download new Main firmware, or SET STAT 2 to execute the Main firmware. Setting STAT=0 forces a firmware reset, which will leave the motors free-spinning (no torque, no braking).
TEMP	Puck™ temperature		R/-		No	The Puck temperature should not exceed 70 ˚C for extended periods.
THERM	Thermistor (motor) temperature		R/-		No	The motor temperature should not exceed 125 ˚C for extended periods.
VALUE	Value to poke/peek		R/W		No	Use with ADDR to read/write data from the Puck memory.	Read the TMS320F2812 DSP’s GPBDAT register; setProperty(0, 4, ADDR, FALSE, 28900); getProperty(0, 4, VALUE, &longVal);
VBUS	The bus voltage on a Puck™		R/-		No	The standard Puck is designed for operation between 18V and 90V. However, contact Barrett Technology if operating the bus at a voltage other than 48 V.
VERS	Firmware version (or the monitor version, if the Puck™ is in reset)		R/W		No
VLOGIC			R/-		No	Not yet implemented
X0, X1, X2			R/W		Yes	N/A
X3, X4, X5			R/W		Yes
X6, X7			R/W		Yes

Motor Properties

These properties are used only by the motor controllers (not the safety module).

ACCEL			R/W	2048	Yes
CT	32-Bit Close Target		R/W	30000	Yes
CTS	32-Bit Counts per revolution		R/W	4096	Yes	CTS
DP	32-Bit Default Position		R/W	0	Yes
DS			R/W	25000	Yes
E	32-Bit Endpoint		R/W	0	No
ECMAX	Encoder Correction Maximum Value		R/W	0	No
ECMIN	Encoder Correction Minimum Value		R/W	0	No
EN			R/W		No
HALLH	32-Bit Hall History Bitfield		R/W	0	No
HALLS	Hall feedback bitfield: CBA		R/W		No
HOLD	Flag to hold position after move		R/W	0	Yes
HSG			R/W	255	Yes
IKCOR	Current sense correction factor		R/W	1638	Yes
IKI	Current sense integral gain		R/W	3276	Yes
IKP	Current sense proportional gain		R/W	8192	Yes
IOFF	32-Bit Intialization Offset		R/W		Yes
IOFST	Current Offset Calibration		R/W		Yes
IPNM	The puck torque unit to Nm (Command Current / Nm) conversion is stored here		R/W	2755	Yes	IPNM is set at the factory. IPNM is never actually used in the pucks themselves. It is simply a non-volatile place to store the conversion constant so that the controlling PC can read it upon startup and use it to convert between puck units and SI units of torque for the end user.
IVEL			R/W	20	Yes
JIDX			R/W		Yes
KD			R/W	8000	Yes
KI			R/W	0	Yes
KP			R/W	2000	Yes
LCTC			R/W	1	No
LCVC			R/W	1	No
LFLAGS			R/W	0	No
LSG			R/W	0	Yes
M	32-Bit Mechanical Angle in ENCODER counts?		-/W		No
MCV	In counts/ms		R/W	1500	Yes
MDS	Max Duty Sum for Power Limiting		R/W	1650	Yes
MECH	Mechanical encoder angle		R/-		No	For magnetic encoders, MECH is the raw encoder feedback, absolute within one rotation of the motor. For optical encoders, MECH is the number of encoder counts between the present location and the index pulse. (See Appendix C for details about MECH with optical encoders).
MOFST	Mechanical Offset Calibration		R/W		Yes	Calibrated at lab. MOFST is the encoder reading at the start of an electrical cycle. (See Appendix C for details about MOFST with Optical Encoders).
MOV	Counts/ms		R/W	1500	Yes
MPE			R/W	5	Yes
MT	The maximum torque a Puck™ will apply, even if commanded to apply more (in milliamps).		R/W	4700	Yes	OpenWAM() calls InitializeSystem() (see the Doxygen documentation) which sets MT to 4731 for each puck. A value of 1024 corresponds to 1.00A of current in the motor windings. Let's say MT = 750, TL1 = 2500, TL2 = 4000. You send a T of 2800. The safety system is okay with this, it just shows the warning light on the pendant. The puck notices that abs(2800) exceeds 750, so it sets its own torque output to 750 * sign(2800).
MV	Maximum Velocity in counts/millisecond		R/W	1500	Yes
OD			R/W		Yes
OT	32-Bit Open Target		R/W	0	Yes
P	Motor position in encoder counts.		R/W		Yes	You can set P in a puck only when the puck's MODE = 0 (MODE = MODE_IDLE). Just be careful to set IFAULT (see Safety-Module properties section below) in the safety module before you do this, else you will likely get a velocity fault
PIDX	Puck™ Index for Torque		R/W		Yes
POLES	Number of magnets on rotor		R/W	12, 8, or 6, depending on motor type	Yes
T	Set the Puck™ torque (in milliamps)		R/W	0	No	The pucks will apply the last received torque until a new torque is sent, or the MODE changes to MODE_IDLE.
TENSO			R/W		Yes
TENST			R/W		Yes
TIE	Flag to tie inner and outer links		R/W	0	Yes
TSTOP	Time until considered stopped		R/W	1000	Yes
UPSECS	The total power-up time for this WAM		R/W		Yes
V	Velocity in counts/milliseconds		R/W	0	No

Safety-Module Properties

The Safety Module is an additional Puck located in the base of the WAM (not attached to a motor). The Safety Module has a puck ID of 10, and is identified in the software as SAFETY_MODULE. Its job is to listen to the CANbus traffic and shut the WAM down in the event of an over-torque, over-velocity, voltage problem, or heartbeat error (missing communication from any puck or the PC). It also controls the pendant lights and switches. The properties below are only applicable to the Safety Module. All safety module properties apply to the whole arm on a global basis. For example, if the torque of ANY motor exceeds TL2, the safety system will force the arm into IDLE mode (all phase leads tied together).

Property:	Definition:	Values (Units):	Read/Write:	Default:	Saved:	Notes:
IFAULT	If IFAULT is greater than 0 and a fault is observed by the safety system, IFAULT is decremented by one, and the fault is ignored.	0 to 20 (typical)	0	To set the initial positions of the pucks, you must also set IFAULT (Ignore Fault) at that time to prevent the giant instantaneous position change from causing an over-velocity fault in the safety module. See the DefineWAMpos() function in the Doxygen documentation for an example.
MAXPWR
PEN
PWR
SAFE
TL1, TL2	The safety system’s motor torque warning, fault levels (Puck™ torque units)				TL1 is the minimum torque that will cause a warning; TL2 is the minimum torque that will cause a fault.
VL1, VL2	VL1 is the minimum velocity that will cause a warning; VL2 is the minimum velocity that will cause a fault.	(rad/s or m/s)	0.5, 1.0 (respectively)		Before calling DefineWAMpos() (otherwise known as zeroing the WAM), VL1 and VL2 limit the angular velocity (rad/s) of every joint, and the 7-segment LED display on the pendants will show which joint exceeded the velocity limit if a velocity warning or fault occurs. After DefineWAMpos() is called, the WAM switches to limiting the Cartesian velocity (m/s) of the elbow and 4-DOF endpoint, instead of each joint’s velocity. In the event of a fault after DefineWAMpos() is called, the 7-segment LED display on the pendants will show “E” or “A” to indicate whether the Elbow or the Arm endpoint exceeded the velocity limit. The value of these limits can be changed at any time, but both limits are always applicable to the entire robot – the limits cannot be applied only to particular joints or points on the WAM.

If you want to set these properties directly (using setProperty()), please note that they are in Q4.12 notation, so take whatever you want the value to be and multiply it by 4096 before you set it. Q4.12 means "4 bits of integer, 12 bits of fraction". 0x1000 = 1.0, 0x1800 = 1.5, 0x7800 = 7.5. If you go much higher, you'll go negative (do not do this). See the source code for SetSafetyLimits() in src/btwam/btwam.c for an example.

VNOM
VOLTH1, VOLTH2	The safety system’s high voltage warning, fault limit	Volts	54, 57		If the bus voltage exceeds VOLTH1, the safety system will begin bleeding off bus voltage through a resistor, and the pendants will display a voltage warning with the letter ‘H’. If the bus voltage exceeds VOLTH2, the safety system will disconnect the bus and clamp it, and the pendants will display a voltage fault with the letter ‘H’.
VOLTL1, VOLTL2	The safety system’s low voltage warning, fault limit.	Volts	36, 30		If the bus voltage falls below VOLTL1, the pendants will display a voltage warning with the letter ‘L’. If the bus voltage falls below VOLTL2, the safety system will disconnect the bus and clamp it, and the pendants will display a voltage fault with the letter ‘L’.
ZERO	After sending the pucks their known initial position, set the safety system's ZERO property to 1 so it can start calculating Cartesian velocities.				Use the DefineWAMpos() function in src/btwam/btwam.c to set the initial positions of the other motor controllers. This is called automatically during the normal OpenWAM() call.

Key to Property Table

Key	Param.	45	MV	91	IKP
0	VERS	46	MCV	92	IKI
1	ROLE	47	MOV	93	IKCOR
2	SN	48	P	94	HOLD
3	ID	49	P2	95	TIE
4	ERROR	50	DP	96	ECMAX
5	STAT	51	DP2	97	ECMIN
6	ADDR	52	E	98	LFLAGS
7	VALUE	53	E2	99	LCTC
8	MODE	54	OT	100	LCVC
9	TEMP	55	OT2
10	PTEMP	56	CT
11	OTEMP	57	CT2
12	BAUD	58	M
13	LOCK	59	M2
14	DIG0	60	DS
15	DIG1	61	MOFST
16	FET0	62	IOFST
17	FET1	63	UPSECS
18	ANA0	64	OD
19	ANA1	65	MDS
20	THERM	66	MECH
21	VBUS	67	MECH2
22	IMOTOR	68	CTS
23	VLOGIC	69	CTS2
24	ILOGIC	70	PIDX
25	SG	71	HSG
26	GRPA	72	LSG
27	GRPB	73	IVEL
28	GRPC	74	IOFF
29	CMD	75	IOFF2
30	SAVE	76	MPE
31	LOAD	77	EN
32	DEF	78	TSTOP
33	FIND	79	KP
34	X0	80	KD
35	X1	81	KI
36	X2	82	ACCEL
37	X3	83	TENST
38	X4	84	TENSO
39	X5	85	JIDX
40	X6	86	IPNM
41	X7	87	HALLS
42	T	88	HALLH
43	MT	89	HALLH2
44	V	90	POLES