9. Setting reference

The Jrk G2 holds all of its settings in its non-volatile EEPROM memory. These settings are normally set ahead of time over USB using the Jrk G2 Configuration Utility. You can also read and write settings from the Jrk over USB using the --get-settings and --settings arguments to jrk2cmd. You can use the Jrk’s “Get settings” command to read these settings over serial and I²C, but you cannot change the EEPROM settings using those interfaces.

The Jrk stores a temporary copy of its settings in RAM, and the “Set RAM settings” and “Get RAM settings” commands allow you read and write from this copy over serial, I²C, and USB. This allows you to temporarily override most (but not all) settings.

This section lists all of the settings that the Jrk G2 supports. For each setting, this section contains several pieces of information:

• The Offset of each setting is the location where it is stored in the Jrk’s EEPROM memory. The offset is measured in bytes. You can use this offset with the “Read setting” and “Set setting” commands.
• The Type of each setting specifies how many bits the setting occupies, and says whether it is signed or unsigned (if applicable). All the multi-byte settings use little-endian format, meaning that the least-significant byte comes first.
• The Data entry for each setting specifies how the data for that setting is encoded in the Jrk’s memory. Some of the settings lack this field because they are simply dimensionless integers, so their encoding is straightforward.
• The Default entry for each setting is the default value it has on a new Jrk or a Jrk that has been reset to its defaults.
• The Range entry for each setting specifies what values the setting can have, if applicable. Trying to use a value outside of this range could result in unexpected behavior.
• The Settings file is the name of the setting in a Jrk settings file, if applicable. You can save and load Jrk settings files from the “File” menu of the Configuration utility, or by using the Jrk Command-line Utility (jrk2cmd).
• The Settings file data entry for each setting is the specification of how that setting is encoded in a settings file. Some of the settings lack this field because the encoding is straightforward.
• The Configuration utility entry is the location of that setting in the graphical user interface of the Jrk G2 configuration utility software, if applicable.
• The Temporary override available entry is “Yes” if changes made to the setting with the “Set RAM settings” command will have an immediate effect. Otherwise, you will need to set this setting ahead of time over USB using Jrk G2 configuration software.

List of settings

• Input mode
• Input error minimum
• Input error maximum
• Input minimum
• Input maximum
• Input neutral minimum
• Input neutral maximum
• Target minimum
• Target neutral
• Target maximum
• Invert input direction
• Input scaling degree
• Input detect disconnect
• Input analog samples exponent
• Feedback mode
• Feedback error minimum
• Feedback error maximum
• Feedback minimum
• Feedback maximum
• Invert feedback direction
• Feedback detect disconnect
• Feedback dead zone
• Feedback analog samples exponent
• Feedback wraparound
• Serial mode
• Serial baud rate
• Serial timeout
• Serial device number
• Never sleep
• Enable CRC
• Enable 14-bit device number
• Disable compact protocol
• Proportional multiplier
• Proportional exponent
• Integral multiplier
• Integral exponent
• Derivative multiplier
• Derivative exponent
• PID period
• Integral divider exponent
• Integral limit
• Reset integral when proportional term exceeds max duty cycle
• PWM frequency
• Current samples exponent
• Hard overcurrent threshold
• Current offset calibration
• Current scale calibration
• Invert motor direction
• Max. duty cycle forward
• Max. duty cycle reverse
• Max. duty cycle while feedback is out of range
• Max. acceleration forward
• Max. acceleration reverse
• Max. deceleration forward
• Max. deceleration reverse
• Hard current limit forward
• Hard current limit reverse
• Brake duration forward
• Brake duration reverse
• Soft current limit forward
• Soft current limit reverse
• Soft current regulation level forward
• Soft current regulation level reverse
• Coast when off
• Error enable
• Error latch
• Error hard stop
• VIN calibration
• Disable I²C pull-ups
• Enable pull-up for analog input on SDA/AN
• Always configure SDA/AN for analog input
• Always configure FBA for analog input
• FBT method
• FBT timing clock
• FBT timing polarity
• FBT timing timeout
• FBT samples
• FBT divider exponent
• Not initialized

Input mode

Offset	0x03
Type	unsigned 8-bit
Data	0: Serial / I²C / USB 1: Analog voltage 2: RC
Default	Serial / I²C / USB
Settings file	input_mode
Settings file data	serial analog rc
Configuration utility	Input tab, Input mode
Temporary override available	No

The input mode setting specifies how you want to control the Jrk. It determines the definition of the input and target variables. The input variable is a raw measurement of the Jrk’s input. The target variable is the desired state of the system’s output, and feeds into the PID feedback algorithm.

• If the input mode is “Serial / I²C / USB”, the Jrk gets its input and target settings over its USB, serial, or I²C interfaces. You can send Set Target commands to the Jrk to set both the input and target variables.
• If the input mode is “Analog voltage”, the Jrk gets it input variable by reading the voltage on its SDA/AN pin. A signal level of 0 V corresponds to an input value of 0, and a signal level of 5 V corresponds to an input value of 4092. The Jrk uses its input scaling feature to set the target variable.
• If the input mode is “RC”, the Jrk gets it input variable by reading RC pulses on its RC pin. The input value is the width of the most recent pulse, in units of 2/3 microseconds (0.666 μs). The Jrk uses its input scaling feature to set the target variable.

Input error minimum

Offset	0x04
Type	unsigned 16-bit
Default	0
Range	0 to 4095
Settings file	input_error_minimum
Configuration utility	Input tab, Scaling box, Input column, Error min
Temporary override available	Yes

If the raw input value is below this value, it causes an “Input disconnect” error. See Section 7.3.

Input error maximum

Offset	0x06
Type	unsigned 16-bit
Default	4095
Range	0 to 4095
Settings file	input_error_maximum
Configuration utility	Input tab, Scaling box, Input column, Error max
Temporary override available	Yes

If the raw input value is below this value, it causes an “Input disconnect” error. See Section 7.3.

Input minimum

Offset	0x08
Type	unsigned 16-bit
Default	0
Range	0 to 4095
Settings file	input_minimum
Configuration utility	Input tab, Scaling box, Input column, Minimum
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Input maximum

Offset	0x0A
Type	unsigned 16-bit
Default	4095
Range	0 to 4095
Settings file	input_maximum
Configuration utility	Input tab, Scaling box, Input column, Maximum
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Input neutral minimum

Offset	0x0C
Type	unsigned 16-bit
Default	2048
Range	0 to 4095
Settings file	input_neutral_minimum
Configuration utility	Input tab, Scaling box, Input column, Neutral min
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Input neutral maximum

Offset	0x0E
Type	unsigned 16-bit
Default	2048
Range	0 to 4095
Settings file	input_neutral_maximum
Configuration utility	Input tab, Scaling box, Input column, Neutral max
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Target minimum

Offset	0x10
Type	unsigned 16-bit
Default	0
Range	0 to 4095
Settings file	output_minimum
Configuration utility	Input tab, Scaling box, Target column, Minimum
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Target neutral

Offset	0x12
Type	unsigned 16-bit
Default	2048
Range	0 to 4095
Settings file	output_neutral
Configuration utility	Input tab, Scaling box, Target column, Neutral
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Target maximum

Offset	0x14
Type	unsigned 16-bit
Default	4095
Range	0 to 4095
Settings file	output_maximum
Configuration utility	Input tab, Scaling box, Target column, Maximum
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Invert input direction

Offset	bit 0 of byte 0x02
Type	boolean
Data	0: false 1: true
Default	false
Settings file	input_invert
Settings file data	true or false
Configuration utility	Input tab, Scaling box, Invert input direction
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Input scaling degree

Offset	0x16
Type	unsigned 8-bit
Data	0: linear 1: quadratic 2: cubic 3: quartic 4: quintic
Default	JRK_SCALING_DEGREE_LINEAR
Settings file	input_scaling_degree
Settings file data	linear quadratic cubic quartic quintic
Configuration utility	Input tab, Scaling box, Degree
Temporary override available	Yes

This is one of the input scaling parameters that determines how the Jrk calculates its target value from its raw input. See Section 7.3.

Input detect disconnect

Offset	bit 1 of byte 0x02
Type	boolean
Data	0: false 1: true
Default	false
Settings file	input_detect_disconnect
Settings file data	true or false
Configuration utility	Input tab, Detect disconnect with power pin (SCL)
Temporary override available	Yes

This determines whether the Jrk will drive the SCL pin low to detect when the input potentiometer has been disconnected. See Section 7.3.

Input analog samples exponent

Offset	0x17
Type	unsigned 8-bit
Default	7 (128 samples)
Range	0 to 10 (1 sample to 1024 samples)
Settings file	input_analog_samples_exponent
Configuration utility	Input tab, Analog samples
Temporary override available	Yes

This setting specifies how many analog samples of the SDA/AN pin to take each PID period if it is being used as an analog input. The number of samples will be 2^x where x is this setting. For more information, see Section 7.3.

Feedback mode

Offset	0x18
Type	unsigned 8-bit
Data	0: None 1: Analog voltage 2: Frequency (speed control)
Default	None
Settings file	feedback_mode
Settings file data	none analog frequency
Configuration utility	Feedback tab, Feedback mode
Temporary override available	No

The feedback mode setting specifies whether the Jrk is using feedback from the output of the system, and if so defines what type of feedback to use.

• If the feedback mode is “None”, feedback and PID calculations are disabled, and the Jrk will do open-loop control. The duty cycle target variable is always equal to the target variable minus 2048, instead of being the result of a PID calculation. This means that a target of 2648 corresponds to driving the motor at full speed forward, 2048 is stopped, and 1448 is full-speed reverse. See Section 5.1.
• If the feedback mode is “Analog voltage”, the Jrk gets its feedback by measuring the voltage on the FBA pin. A level of 0 V corresponds to a feedback value of 0, and a level of 5 V corresponds to a feedback value of 4092. The feedback scaling algorithm computes the scaled feedback variable, and the PID algorithm uses the scaled feedback and the target to compute the duty cycle target. See Section 7.4.
• If the feedback mode is “Frequency (speed control)”, the Jrk gets it feedback by measuring the frequency of a digital signal on the FBT pin. This mode is only suitable for speed control, not position control. See Section 7.4.

Feedback error minimum

Offset	0x19
Type	unsigned 16-bit
Default	0
Range	0 to 4095
Settings file	feedback_error_minimum
Configuration utility	Feedback tab, Error min
Temporary override available	Yes

If the raw feedback value is below this value, it causes a “Feedback disconnect” error. See Section 7.4.

Feedback error maximum

Offset	0x1B
Type	unsigned 16-bit
Default	4095
Range	0 to 4095
Settings file	feedback_error_maximum
Configuration utility	Feedback tab, Error max
Temporary override available	Yes

If the raw feedback value exceeds this value, it causes a “Feedback disconnect” error. See Section 7.4.

Feedback minimum

Offset	0x1D
Type	unsigned 16-bit
Default	0
Range	0 to 4095
Settings file	feedback_minimum
Configuration utility	Feedback tab, Minimum
Temporary override available	Yes

This is one of the parameters of the feedback scaling feature. See Section 7.4.

Feedback maximum

Offset	0x1F
Type	unsigned 16-bit
Default	4095
Range	0 to 4095
Settings file	feedback_maximum
Configuration utility	Feedback tab, Maximum
Temporary override available	Yes

This is one of the parameters of the feedback scaling feature. See Section 7.4.

Invert feedback direction

Offset	bit 2 of byte 0x02
Type	boolean
Data	0: false 1: true
Default	false
Settings file	feedback_invert
Settings file data	true or false
Configuration utility	Feedback tab, Invert feedback direction
Temporary override available	Yes

This is one of the parameters of the feedback scaling feature. See Section 7.4.

Feedback detect disconnect

Offset	bit 3 of byte 0x02
Type	boolean
Data	0: false 1: true
Default	false
Settings file	feedback_detect_disconnect
Settings file data	true or false
Configuration utility	Feedback tab, Detect disconnect with power pin (AUX)
Temporary override available	Yes

This determines whether the Jrk will drive AUX low to detect if the feedback potentiometer has been disconnected. See Section 7.4.

Feedback dead zone

Offset	0x21
Type	unsigned 8-bit
Default	0
Range	0 to 255
Settings file	feedback_dead_zone
Configuration utility	PID tab, Feedback dead zone
Temporary override available	Yes

If PID feedback is enabled, the Jrk sets the duty cycle target to zero and resets the integral whenever the magnitude of the error is smaller than this setting. See Section 7.5.

Feedback analog samples exponent

Offset	0x22
Type	unsigned 8-bit
Default	7 (128 samples)
Range	0 to 10 (1 sample to 1024 samples)
Settings file	feedback_analog_samples_exponent
Configuration utility	Feedback tab, Analog samples
Temporary override available	Yes

This setting specifies how many analog samples of the FBA pin to take each PID period if it is being used as an analog input. The number of samples will be 2^x where x is this setting. The samples are averaged together. For more information, see Section 7.4.

Feedback wraparound

Offset	bit 4 of byte 0x02
Type	boolean
Data	0: false 1: true
Default	false
Settings file	feedback_wraparound
Settings file data	true or false
Configuration utility	Feedback tab, Wraparound
Temporary override available	Yes

This option, which is only available when the feedback mode is “Analog”, determines whether the PID algorithm will consider a scaled feedback value of 0 to be next to a scaled feedback value of 4095 when calculating the error. See Section 7.4.

Serial mode

Offset	0x23
Type	unsigned 8-bit
Data	0: USB dual port 1: USB chained 2: UART
Default	USB dual port
Settings file	serial_mode
Settings file data	usb_dual_port usb_chained uart
Configuration utility	Input tab, Serial interface box (radio buttons)
Temporary override available	No

The serial mode determines how bytes are transferred between the Jrk’s UART (TX and RX pins), its two USB virtual serial ports (the command port and the TTL Port), and its serial command processor.

• If the serial mode is “USB dual port”, the command port can be used to send commands to the Jrk and receive responses from it, while the TTL port can be used to send and receives bytes on the TX and RX lines. The baud rate set by the USB host on the TTL port determines the baud rate used on the TX and RX lines.
• If the serial mode is “USB chained”, the command port can be used to both transmit bytes on the TX line and send commands to the Jrk. The Jrk’s responses to those commands will be sent to the command port but not the TX line. If the RX line is enabled as a serial receive line, bytes received on the RX line will be sent to the command port but will not be interpreted as command bytes by the Jrk. The baud rate set by the USB host on the command port determines the baud rate used on the TX and RX lines.
• If the serial mode is “UART”, the TX and RX lines can be used to send commands to the Jrk and receive responses from it. Any byte received on RX will be sent to the command port, but bytes sent from the command port will be ignored.

Serial baud rate

Offset	0x24
Type	unsigned 16-bit
Data	16-bit baud rate generator (see below)
Default	0x4E1 (9600 bits per second)
Settings file	serial_baud_rate
Settings file data	Baud rate in bits per second
Configuration utility	Input tab, Serial interface box, fixed baud rate
Temporary override available	No

This setting specifies the baud rate to use on the RX and TX pins when the serial mode is UART. In other serial modes, the baud rate defaults to 9600, but can be changed over USB using the standard USB CDC ACM command.

The settings file and the configuration utility show the baud rate in bits per second, but it is actually stored on the Jrk as an unsigned 16-bit integer called the baud rate generator. The baud rate will be 12 Mbps divided by the baud rate generator.

Serial timeout

Offset	0x26
Type	unsigned 16-bit
Data	Timeout in units of 10 ms
Default	0
Range	0 to 655,350 ms
Settings file	serial_timeout
Settings file data	Timeout in units of milliseconds
Configuration utility	Input tab, Serial interface, Timeout (s)
Temporary override available	Yes

This is the time before the device reports a “Serial timeout error” if it has not received certain commands. A value of 0 disables the command timeout feature. See Section 7.7 for details about the serial timeout error.

The configuration utility presents the timeout in seconds, with two digits after the decimal point. The settings file has the timeout in units of milliseconds. The Jrk itself stores it as an unsigned 16-bit number with units of 10 ms, so the maximum possible value is 655,350 ms.

Serial device number

Offset	0x28
Type	unsigned 16-bit
Default	11
Range	0 to 16383
Settings file	serial_device_number
Configuration utility	Input tab, Serial interface, Device number
Temporary override available	No

This is the serial device number used in the Pololu protocol on the Jrk’s serial interfaces, and the I²C device address used on the Jrk’s I²C interface.

By default, the Jrk only pays attention to the lower 7 bits of this setting, but if you enable 14-bit serial device numbers then it will use the lower 14 bits for the serial interface (but the I²C interface will still only use the lower 7 bits).

See Section 12 and Section 13.

Never sleep

Offset	bit 0 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	never_sleep
Settings file data	true or false
Configuration utility	Advanced tab, Miscellaneous, Never sleep (ignore USB suspend)
Temporary override available	Yes

By default, if the Jrk is powered from a USB bus that is in suspend mode (e.g. the computer is sleeping) and VIN power is not present, it will go to sleep to reduce its current consumption and comply with the USB specification. If this setting is set to true, the Jrk will never go to sleep.

Enable CRC

Offset	bit 1 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	serial_enable_crc
Settings file data	true or false
Configuration utility	Input tab, Serial interface, Enable CRC
Temporary override available	No

If set to true, the Jrk requires a 7-bit CRC byte at the end of each serial command, and if the CRC byte is wrong then it ignores the command and sets the serial CRC error bit. See Section 12.

Enable 14-bit device number

Offset	bit 2 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	serial_enable_14bit_device_number
Settings file data	true or false
Configuration utility	Input tab, Serial interface, Enable 14-bit device number
Temporary override available	No

If enabled, the Jrk’s Pololu protocol for serial commands will require a 14-bit device number to be sent with every command, instead of normal 7-bit device number. This option allows you to put more than 128 Jrk devices on one serial bus and control them individually. See Section 12.

Disable compact protocol

Offset	bit 3 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	serial_disable_compact_protocol
Settings file data	true or false
Configuration utility	Input tab, Serial interface, Disable compact protocol
Temporary override available	No

If enabled, the Jrk will not respond to compact protocol serial commands. See Section 12.

Proportional multiplier

Offset	0x51
Type	unsigned 16-bit
Default	0
Range	0 to 1023
Settings file	proportional_multiplier
Configuration utility	PID tab, Proportional coefficient, Upper left
Temporary override available	Yes

This is the multiplier for the proportional coefficient used in the PID calculation. See Section 7.5.

Proportional exponent

Offset	0x53
Type	unsigned 8-bit
Default	0
Range	0 to 18
Settings file	proportional_exponent
Configuration utility	PID tab, Proportional coefficient, Lower left
Temporary override available	Yes

This is the exponent for the proportional coefficient used in the PID calculation. See Section 7.5.

Integral multiplier

Offset	0x54
Type	unsigned 16-bit
Default	0
Range	0 to 1023
Settings file	integral_multiplier
Configuration utility	PID tab, Integral coefficient, Upper left
Temporary override available	Yes

This is the multiplier for the integral coefficient used in the PID calculation. See Section 7.5.

Integral exponent

Offset	0x56
Type	unsigned 8-bit
Default	0
Range	0 to 18
Settings file	integral_exponent
Configuration utility	PID tab, Integral coefficient, Lower left
Temporary override available	Yes

This is the exponent for the integral coefficient used in the PID calculation. See Section 7.5.

Derivative multiplier

Offset	0x57
Type	unsigned 16-bit
Default	0
Range	0 to 1023
Settings file	derivative_multiplier
Configuration utility	PID tab, Derivative coefficient, Upper left
Temporary override available	Yes

This is the multiplier for the derivative coefficient used in the PID calculation. See Section 7.5.

Derivative exponent

Offset	0x59
Type	unsigned 8-bit
Default	0
Range	0 to 18
Settings file	derivative_exponent
Configuration utility	PID tab, Derivative coefficient, Lower left
Temporary override available	Yes

This is the exponent for the derivative coefficient used in the PID calculation. See Section 7.5.

PID period

Offset	0x5A
Type	unsigned 16-bit
Data	PID period in units of milliseconds
Default	10 ms
Range	1 ms to 8191 ms
Settings file	pid_period
Configuration utility	PID tab, PID period
Temporary override available	Yes

The PID period specifies how often the Jrk should calculate its input and feedback, run its PID calculation, and update the motor speed, in units of milliseconds. This period is still used even if feedback and PID are disabled. See Section 7.5.

Integral divider exponent

Offset	0x3F
Type	unsigned 8-bit
Default	0
Range	0 to 15
Settings file	integral_divider_exponent
Configuration utility	PID tab, Integral divider
Temporary override available	Yes

This setting determines the “Integral divider” described in Section 7.5. The integral divider is 2^x where x is this setting.

Integral limit

Offset	0x5C
Type	unsigned 16-bit
Default	1000
Range	0 to 32767
Settings file	integral_limit
Configuration utility	PID tab, Integral limit
Temporary override available	Yes

See Section 7.5.

Reset integral when proportional term exceeds max duty cycle

Offset	bit 0 of byte 0x50
Type	boolean
Data	0: false 1: true
Default	false
Settings file	reset_integral
Settings file data	true or false
Configuration utility	PID tab, Reset integral when proportional term exceeds max duty cycle
Temporary override available	Yes

See Section 7.5.

PWM frequency

Offset	0x32
Type	unsigned 8-bit
Data	0: 20 kHz 1: 5 kHz
Default	20 kHz
Settings file	pwm_frequency
Settings file data	20 or 5
Configuration utility	Motor tab, PWM frequency
Temporary override available	Yes

See Section 7.6.

Current samples exponent

Offset	0x33
Type	unsigned 8-bit
Default	7 (128 samples)
Range	0 to 10 (1 sample to 1024 samples)
Settings file	current_samples_exponent
Configuration utility	Motor tab, Current samples
Temporary override available	Yes

This setting specifies how many analog samples of the Jrk’s internal current sense pin to take each PID period. The number of samples will be 2^x where x is this setting. The samples are averaged together. For more information, see Section 7.6.

Hard overcurrent threshold

Offset	0x34
Type	unsigned 8-bit
Default	1
Range	1 to 255
Settings file	hard_overcurrent_threshold
Configuration utility	Motor tab, Hard overcurrent threshold
Temporary override available	Yes

This setting is only available for the Jrk G2 18v19, 24v13, 18v27, and 24v21. See Section 7.6.

Current offset calibration

Offset	0x35
Type	signed 16-bit
Default	0
Range	-800 to 800
Settings file	current_offset_calibration
Configuration utility	Motor tab, Current offset calibration
Temporary override available	Yes

See Section 7.6.

Current scale calibration

Offset	0x37
Type	signed 16-bit
Default	0
Range	-1875 to 1875
Settings file	current_scale_calibration
Configuration utility	Motor tab, Current scale calibration
Temporary override available	Yes

See Section 7.6.

Invert motor direction

Offset	bit 5 of byte 0x02
Type	boolean
Data	0: false 1: true
Default	false
Settings file	motor_invert
Settings file data	true or false
Configuration utility	Motor tab, Invert motor direction
Temporary override available	Yes

Flips the polarity of the voltage applied to the motor. See Section 7.6.

Max. duty cycle forward

Offset	0x68
Type	unsigned 16-bit
Default	600
Range	0 to 600
Settings file	max_duty_cycle_forward
Configuration utility	Motor tab, Max. duty cycle, Forward column
Temporary override available	Yes

See Section 7.6.

Max. duty cycle reverse

Offset	0x6A
Type	unsigned 16-bit
Default	600
Range	0 to 600
Settings file	max_duty_cycle_reverse
Configuration utility	Motor tab, Max. duty cycle, Reverse column
Temporary override available	Yes

See Section 7.6.

Max duty cycle while feedback is out of range

Offset	0x5E
Type	unsigned 16-bit
Default	600
Range	1 to 600
Settings file	max_duty_cycle_while_feedback_out_of_range
Configuration utility	Motor tab, Max. duty cycle while feedback is out of range
Temporary override available	Yes

See Section 7.6.

Max. acceleration forward

Offset	0x60
Type	unsigned 16-bit
Default	600
Range	1 to 600
Settings file	max_acceleration_forward
Configuration utility	Motor tab, Max. acceleration, Forward column
Temporary override available	Yes

See Section 7.6.

Max. acceleration reverse

Offset	0x62
Type	unsigned 16-bit
Default	600
Range	1 to 600
Settings file	max_acceleration_reverse
Configuration utility	Motor tab, Max. acceleration, Reverse column
Temporary override available	Yes

See Section 7.6.

Max. deceleration forward

Offset	0x64
Type	unsigned 16-bit
Default	600
Range	1 to 600
Settings file	max_deceleration_forward
Configuration utility	Motor tab, Max. deceleration, Forward column
Temporary override available	Yes

See Section 7.6.

Max. deceleration reverse

Offset	0x66
Type	unsigned 16-bit
Default	600
Range	1 to 600
Settings file	max_deceleration_reverse
Configuration utility	Motor tab, Max. deceleration, Reverse column
Temporary override available	Yes

See Section 7.6.

Hard current limit forward

Offset	0x6C
Type	unsigned 16-bit
Data	Encoded
Default	Depends on the product
Settings file	encoded_hard_current_limit_forward
Configuration utility	Motor tab, Hard current limit, Forward column
Temporary override available	Yes

This setting specifies the hardware current limit that the Jrk will use when driving in the forward direction.

This setting is not actually stored in the Jrk as a current; it is stored as an encoded value telling the Jrk how to set up its current limiting hardware. The correspondence between the encoded value and the actual current limit in milliamps depends on what product you are using and the characteristics of your particular unit as represented by the “Current offset calibration” and “Current scale calibration” settings. You can get a table in CSV format showing the correspondence by connecting the Jrk into a computer via USB and running jrk2cmd --current-table.

The default value for this setting depends on what Jrk product you have, as described in the table below:

Jrk product	Default hard current limit
18v19	28.47 A (86)
24v13	19.34 A (62)
18v27	40.25 A (87)
24v21	31.53 A (63)

This setting is only available for the Jrk G2 18v19, 24v13, 18v27, and 24v21. See Section 7.6 for more information.

Hard current limit reverse

Offset	0x6E
Type	unsigned 16-bit
Data	Encoded
Default	Depends on the product
Settings file	encoded_hard_current_limit_reverse
Configuration utility	Motor tab, Hard current limit, Reverse column
Temporary override available	Yes

See the hard current limit forward setting. This setting is the same except it applies when driving in the reverse direction. This setting is only available for the Jrk G2 18v19, 24v13, 18v27, and 24v21.

Brake duration forward

Offset	0x70
Type	unsigned 8-bit
Data	Duration in units of 5 ms
Default	0
Range	0 to 1275 ms
Settings file	brake_duration_forward
Settings file data	Duration in units of milliseconds
Configuration utility	Motor tab, Brake duration, Forward column
Temporary override available	Yes

See Section 7.6.

Brake duration reverse

Offset	0x71
Type	unsigned 8-bit
Data	Duration in units of 5 ms
Default	0
Range	0 to 1275 ms
Settings file	brake_duration_reverse
Settings file data	Duration in units of milliseconds
Configuration utility	Motor tab, Brake duration, Reverse column
Temporary override available	Yes

See Section 7.6.

Soft current limit forward

Offset	0x72
Type	unsigned 16-bit
Data	Current in units of milliamps, 0 means no limit
Default	0
Range	0 to 65,535 mA
Settings file	soft_current_limit_forward
Settings file data	Current in units of milliamps
Configuration utility	Motor tab, Soft current limit, Forward column
Temporary override available	Yes

See Section 7.6.

Soft current limit reverse

Offset	0x74
Type	unsigned 16-bit
Data	Current in units of milliamps, 0 means no limit
Default	0
Range	0 to 65,535 mA
Settings file	soft_current_limit_reverse
Settings file data	Current in units of milliamps
Configuration utility	Motor tab, Soft current limit, Reverse column
Temporary override available	Yes

See Section 7.6.

Soft current regulation level forward

Offset	0x40
Type	unsigned 16-bit
Data	Current in units of milliamps, 0 means disabled
Default	0
Range	0 to 65,535 mA
Settings file	soft_current_regulation_level_forward
Settings file data	Current in units of milliamps
Configuration utility	Motor tab, Soft current regulation level, Forward column
Temporary override available	Yes

This setting is only available on the Jrk G2 21v3. See Section 7.6.

Soft current regulation level reverse

Offset	0x42
Type	unsigned 16-bit
Data	Current in units of milliamps, 0 means disabled
Default	0
Range	0 to 65,535 mA
Settings file	soft_current_regulation_level_reverse
Settings file data	Current in units of milliamps
Configuration utility	Motor tab, Soft current regulation level, Reverse column
Temporary override available	Yes

This setting is only available on the Jrk G2 21v3. See Section 7.6.

Coast when off

Offset	bit 1 of byte 0x50
Type	boolean
Data	0: false 1: true
Default	false
Settings file	coast_when_off
Settings file data	true or false
Configuration utility	Motor tab, When motor is off
Temporary override available	Yes

See Section 7.6.

Error enable

Offset	0x2A
Type	unsigned 16-bit
Default	0
Settings file	error_enable
Configuration utility	Errors tab
Temporary override available	Yes

This setting holds a bit for each error that the Jrk supports. The correspondence between bits and errors is defined in Section 7.7. The bit is 1 if the corresponding error is enabled, and 0 otherwise. Note that an error that is “Enabled & latched” counts as being enabled.

The “Awaiting command”, “No power”, “Motor driver error”, and “Input invalid” errors are always enabled and cannot be disabled, so the bits corresponding to those errors in this setting are ignored.

Error latch

Offset	0x2C
Type	unsigned 16-bit
Default	0
Settings file	error_latch
Configuration utility	Errors tab
Temporary override available	Yes

This setting holds a bit for each error that the Jrk supports. The correspondence between bits and errors is defined in Section 7.7. The bit is 1 if the corresponding error is enabled and latched, or 0 otherwise.

The bits in this register are ignored for errors that are not enabled. (If an error is not enabled, its error flag will never be set, so there is no concept of the error flag being latched.) Also, the “Awaiting command” error and all the serial errors are always latching errors if they are enabled, so bits corresponding to those errors in this setting are ignored.

Error hard stop

Offset	0x2E
Type	unsigned 16-bit
Default	0
Settings file	error_hard
Configuration utility	Errors tab
Temporary override available	Yes

This setting holds a bit for each error that the Jrk supports. The correspondence between bits and errors is defined in Section 7.7. The bit is 1 if the corresponding error is configured as a hard stop error, or 0 otherwise.

The “No power” and “Motor driver” errors are always hard stop errors. The bits corresponding to those errors in this setting are ignored.

VIN calibration

Offset	0x30
Type	signed 16-bit
Default	0
Range	-500 to 500
Settings file	vin_calibration
Configuration utility	Advanced tab, Miscellaneous, VIN measurement calibration
Temporary override available	Yes

The firmware uses this calibration factor when calculating the VIN voltage. One of the steps in the process is to multiply the VIN voltage reading by 825 plus the VIN calibration. Therefore, for every 8 counts that you add or subtract from the VIN calibration setting, you increase or decrease the VIN voltage reading by about 1%.

Disable I²C pull-ups

Offset	bit 4 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	disable_i2c_pullups
Settings file data	true or false
Configuration utility	Advanced tab, Disable I²C pull-ups
Temporary override available	No

This option disables the internal pull-up resistors on the SDA/AN and SCL pins if those pins are being used for I²C communication. Normally, the pull-ups are enabled to ensure that each bus line goes high when no devices are driving it.

Enable pull-up for analog input on SDA/AN

Offset	bit 5 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	analog_sda_pullup
Settings file data	true or false
Configuration utility	Advanced tab, Enable pull-up for analog input on SDA/AN
Temporary override available	No

This option enables the internal pull-up resistor on the SDA/AN pin if it is being used as an analog input.

Always configure SDA/AN for analog input

Offset	bit 6 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	always_analog_sda
Settings file data	true or false
Configuration utility	Advanced tab, Always configure SDA/AN for analog input
Temporary override available	No

This option causes the Jrk to perform analog measurements on the SDA/AN pin and configure SCL as a potentiometer power pin even if the “Input mode” setting is not “Analog”.

Always configure FBA for analog input

Offset	bit 7 of byte 0x01
Type	boolean
Data	0: false 1: true
Default	false
Settings file	always_analog_fba
Settings file data	true or false
Configuration utility	Advanced tab, Always configure FBA for analog input
Temporary override available	No

This option causes the Jrk to perform analog measurements on the FBA pin even if the “Feedback mode” setting is not “Analog”.

FBT method

Offset	0x39
Type	unsigned 8-bit
Data	0: Pulse counting 1: Pulse timing
Default	Pulse counting
Settings file	fbt_method
Settings file data	counting timing
Configuration utility	Feedback tab, Frequency feedback on FBT, Measurement method
Temporary override available	No

See Section 7.4.

FBT timing clock

Offset	bits 4 through 6 of byte 0x3A
Type	unsigned 8-bit
Data	0: 12 MHz 1: 6 MHz 2: 3 MHz 3: 1.5 MHz 4: 48 MHz 5: 24 MHz
Default	1.5 MHz
Range	0 to JRK_FBT_TIMING_CLOCK_24
Settings file	fbt_timing_clock
Settings file data	12m 6m 3m 1m5 48m 24m
Configuration utility	Feedback tab, Frequency feedback on FBT, Pulse timing clock
Temporary override available	No

See Section 7.4.

FBT timing polarity

Offset	bit 0 of byte 0x3A
Type	boolean
Data	0: Active high 1: Active low
Default	Active high
Settings file	fbt_timing_polarity
Settings file data	false (active high) or true (active low)
Configuration utility	Feedback tab, Frequency feedback on FBT, Pulse timing polarity
Temporary override available	No

By default, the pulse timing mode on the FBT pin measures the time of high pulses. When true, this option causes it to measure low pulses. See Section 7.4.

FBT timing timeout

Offset	0x3B
Type	unsigned 16-bit
Data	Timeout in milliseconds
Default	100
Range	1 to 60000
Settings file	fbt_timing_timeout
Configuration utility	Feedback tab, Frequency feedback on FBT, Pulse timing timeout
Temporary override available	Yes

The pulse timing mode for the FBT pin will assume the motor has stopped, and start recording maximum-width pulses if it has not seen any pulses in this amount of time. See Section 7.4.

FBT samples

Offset	0x3D
Type	unsigned 8-bit
Default	1
Range	1 to 32
Settings file	fbt_samples
Configuration utility	Feedback tab, Frequency feedback on FBT, Pulse samples
Temporary override available	No

The number of consecutive FBT measurements to average together in pulse timing mode or to add together in pulse counting mode. See Section 7.4.

FBT divider exponent

Offset	0x3E
Type	unsigned 8-bit
Default	0
Range	0 to 15
Settings file	fbt_divider_exponent
Configuration utility	Feedback tab, Frequency feedback on FBT, Frequency divider
Temporary override available	Yes

This setting determines the “Frequency divider” described in Section 7.4. The frequency divider is 2^x where x is this setting.

Not initialized

Offset	0x00
Type	unsigned 8-bit
Data	0: false non-zero: true
Default	false

This special setting keeps track of whether the rest of the settings have been initialized or not. Normally it is zero, which means false. If you set it to a non-zero value, then the Jrk will reset all of the settings to their default values the next time the Jrk is reset or reinitialized. This is how the “Restore default settings” command in the Jrk G2 Configuration Utility and the --restore-defaults option in the command-line utility are implemented.