OW Command — OneWire Device Query

Query the status of devices connected to OneWire ports, including iButton keys and temperature sensors.

What is it for?

Use case	Description
🔑 Driver identification	Read iButton keys for access control
🌡️ Temperature sensors	Detect DS18B20, DS18S20, DS1822 sensors
🆔 Unique ROM ID	Get 64-bit device identifier
⏱️ Data age	Know how long ago the device was detected

Description

The OneWire system provides communication with temperature sensors and iButton keys through the 1-Wire protocol. The QOW command allows querying the current status of OneWire ports, while the OWP00 and OWP01 signals generate events when activity is detected.

Feature	Description
OneWire	Serial communication protocol that allows multiple devices on a single cable
iButton	Electronic identification keys based on Dallas/Maxim technology
Sensors	DS18S20, DS1822, DS18B20 compatible with 1-Wire protocol
Dual Port	Support for two independent OneWire ports (Port 0 and Port 1)

Syntax

Query


QOWxx

Parameter	Description
xx	OneWire port number (`00` or `01`)

Response


ROWxx,XXXXXXXXXXXXXXXX,AA

Field	Description
ROW	OneWire response prefix
xx	Queried port number (`00` or `01`)
XXXXXXXXXXXXXXXX	Device ROM ID in hexadecimal format (16 characters)
AA	Data age in hexadecimal format (seconds since last reading)

Associated Signals

Signal	Description
`OWP00`	Activity event on OneWire port 0
`OWP01`	Activity event on OneWire port 1

The OWP00 and OWP01 signals are generated automatically when activity is detected on OneWire ports.

Examples

Query Port 0


>QOW00<
>ROW00,01234567890ABCDEF,05;ID=037883;*3A<

Reading with 5 seconds age.

Query Port 1


>QOW01<
>ROW01,FEDCBA0987654321,0A;ID=037883;*2B<

Reading with 10 seconds age (0x0A = 10).

Command	Description
DT	OneWire temperature reading
CXOW	OneWire port configuration

Compatibility

💾Firmware v1.03.00

SPLegacy

ULLegacy

Spider:2 OW ports

Ultralite:1 OW port

💾Firmware v1.00.00

SP-IOT

SM-IOT

Spider IoT:1 OW port

Smart IoT:2 OW ports