The Otii Ace Pro has the voltage(+) and voltage(-) binding post (red and black connectors located on the right side of the instrument), which are used to source the DUT but also to measure the current, voltage, and power of the device. The DUT can be connected through its battery connectors or DC input; refer to the connection diagram below for better understanding.

Ace connected to DUT

To power up the Otii Ace Pro and enable the communication with the host computer, use the provided USB C cable to connect the unit to your computer.

Ace connected to a computer

Check out the Wiring up page to explore all possible connection configurations between the Otii Ace Pro and your DUT.

Expansion Port

The expansion port on the front of the Otii Ace Pro is designed to enhance the hardware's functionality, allowing users to measure additional voltages and currents or trigger external events. These additional pins feature multi-input and multi-output for analog and digital signals, serial communication, and additional power and ground points. Below is a general overview of the additional pins available:

Connector	Description	Maximum rating
0-15V	Adjustable output between 0V and 15V	600 mA
DGND	Digital ground (return current)
RX	UART RX / Digital Input (Exclusively under Scripting)	0 V to 5.5 V
TX	UART TX / Digital Output (Exclusively under Scripting)	0 V to 5.5 V
GPI1	Digital input 1	0 V to 5.5 V
GPI2	Digital input 2	0 V to 5.5 V
GPO1	Digital Output 1	0 V to 5.5 V
GPO2	Digital Output 2	0 V to 5.5 V
DGND	Digital ground (return current)
AGND	Analog ground (return current) / Analog measurements
ADC+	Differential input for current measurement. It also measures single ended voltage with respect to AGND	-10 V to 25 V
ADC-	Input for current measurement	-10 V to 25 V
SENSE+	Analog input with the AGND as reference/return	-10 V to 25 V
SENSE-	Analog input with the AGND as reference/return	-10 V to 25 V

Status LED

The table below explains the Otii Ace Pro's status LED behaviors and their meanings to help you quickly identify the device's state.

LED behavior	Otii Ace Pro Status
Solid blue	Otii Ace Pro is active
Solid green	Relay closed, sinking/sourcing power or in-line mode
Flashing white	Calibrating
Flashing red/blue	Upgrading firmware

Ace Tech spec

General

Operating environment	Min	Typical	Max
Temperature	10°C / 50°F		30°C / 86°F
Humidity	30 %		60 %

Main

Power supply	Min	Typical	Max
Output voltage	0 V		25 V
Output voltage setting resolution		1 mV
Self-consumption		3.5 W
Output power, max continuous		30 W ¹⁰ ¹⁴
Output power, max peak		50 W ¹⁰
Voltage between USB/DC jack and Main –	-200 V		-200 V
Voltage between DGND/AGND and Main –	-200 V		-200 V

Programmable current sink (requires an Otii Toolbox)	Min	Typical	Max
Sink current	0 A		5 A
Sink current, setting resolution		1 µA
Sink voltage	0 V		25 V
Sink power, max continuous		15 W
Sink power, max peak		125 W

Current measurement	Min	Typical	Max
Accuracy -5A to 5 A		±(0.05 % + 25 nA)
Resolution		0.4 nA
Sample rate		50 ksps
Analog bandwidth (3 dB)		50 kHz

Voltage measurement	Min	Typical	Max
Accuracy		±(0.01 % + 1 mV)
Sample rate		50 ksps
Analog bandwidth (3 dB)		50 kHz
Output voltage readback resolution		3.5 µV

Expansion port

UART	Min	Typical	Max
Bitrate	50 bps		5.25 Mbps

Digital I/O	Min	Typical	Max
Digital IO operating voltage	1.2 V	Vio ¹⁵	5 V
VIL Low-level input voltage			Vio * 0.2 V
VIH High-level input voltage	Vio * 0.8 V
Imax, Max sink/source current (total for GPIOs)	-10 mA		10 mA

Differential ADC, pins ADC- and ADC+	Min	Typical	Max
Voltage input	-10 V		25 V
Shunt voltage range	-102.4 mV		102.4 mV
Resolution		12.2 nV
Accuracy		±(0.1 % + 1 µV)
Input impedance		> 100 Mohm

Single ended ADC, pins ADC- and ADC+	Min	Typical	Max
Voltage input	-10 V		25 V
Resolution		3.1 µV
Accuracy		±(0.1 % + 250 µV)
Input impedance		> 100 Mohm

SENSE, pins SENSE- and SENSE+	Min	Typical	Max
Voltage input	-10 V		25 V
Resolution		3.1 µV
Accuracy		±(0.1 % + 250 µV)
Input impedance		> 100 Mohm

Expansion port power supply	Min	Typical	Max
Output voltage	0 V		15 V
Output voltage setting resolution		5 mV
Output current			600 mA
Voltage between USB/DC jack & DGND/AGND	-200 V ¹¹ ¹²		-200 V ¹¹ ¹²

USB and DC jack

DC jack	Min	Typical	Max
Input voltage	7 V		20 V
Input current			5 A

USB	Min	Typical	Max
VBUS voltage ¹³	4.75 V		20 V
VBUS current ¹³			3 A