MAX31826(3)

Thermometer with hardware address pins (DS1825)

3B [.]XXXXXXXXXXXX[XX][/[

See the file man3/temperatures_mini.3so.

| latesttemp | power | prog_addr | temphigh | templow | tempres |

See the file man3/standard_mini.3so.

]]

Digital Temperature Sensor with 1Kb Lockable EEPROM (MAX31826)

3B [.]XXXXXXXXXXXX[XX][/[ temperature | latesttemp | power | memory | pages/page.[0-15|ALL] | prog_addr |

See the file man3/standard_mini.3so.

]]

Cold-Junction Compensated Thermocouple (MAX31850 and MAX31851)

3B [.]XXXXXXXXXXXX[XX][/[ temperature | latesttemp | thermocouple | fault | open_circuit | ground_short | vdd_short | power | prog_addr |

See the file man3/standard_mini.3so.

]]

power

read-only,yes-no
Is the chip powered externally (=1) or from the parasitically from the data bus (=0)?

prog_addr

read-only, 0-15
A distiguishing feature of the DS1825 (3) is the ability to set hardware pins for an address (0-15). This is an alternative to the unique 64-bit address that is set in the factory.

temperature

read-only, floating point
Measured temperature with 12 bit resolution.

For the MAX31850 MAX 31851 this is the cold-junction temperature -- the temperature at the chip. See thermocouple

temperature9 temperature10 temperature11 temperature12

read-only, floating point ( DS1825 only)

Measured temperature at 9 to 12 bit resolution. There is a tradeoff of time versus accuracy in the temperature measurement.

The MAX31826 MAX31850 MAX31851 measure all temperatures at 12 bit resoltion and will return that resolution to all the possible temperature properties.

latesttemp

read-only, floating point
Measured temperature at 9 to 12 bit resolution, depending on the resolution of the latest conversion on this chip. Reading this node will never trigger a temperature conversion. Intended for use in conjunction with /simultaneous/temperature.

fasttemp

read-only, floating point
Equivalent to temperature9

thermocouple

read-only, floating point ( MAX31850 MAX31851 only)

Measured temperature of the thermocouple at 16bit resolution. Cold-junction temperature compensated.

The actual thermocouple type used is set by the selected chip type, and is not discoverable in software.

See the file man3/temperature_threshold.3so.

The MAX31826 does NOT have temperature thresholds and temperature alarm.

See the file man3/temperature_resolution.3so.

pages/page.0 .. pages/page.15 pages/page.ALL

read/write, binary
EEPROM memory pages of 8 bytes each. See the datasheet about locking contents.

memory

read/write, binary
EEPROM memory of 128 bytes. See the datasheet about locking contents.

fault

read-only, yes-no
Fault in last thermocouple conversion

open_circuit

read-only, yes-no
Thermocouple leads disconnected.

ground_short

read-only, yes-no
Thermocouple lead shorted to ground.

vdd_short

read-only, yes-no
Thermocouple lead shorted to supply voltage.

DS1825

The DS1825 (3) is one of several available 1-wire temperature sensors. Alternatives are the DS18S20 (3), DS18B20 (3), and DS1822 (3) as well as temperature/voltage measurements in the DS2436 (3) and DS2438 (3). For truly versatile temperature measurements, see the protean DS1921 (3) Thermachron (3).

The DS1825 (3) can select between 4 resolutionsspanning the fastest/roughest and slowest/best.

MAX31826

The MAX31826 shares a family code with the DS1825 but has differences in some of its functions.

The MAX31826 has 128 btes of EEPROM memory (as 16 pages of 8 bytes) while the DS1825 has no memory available.

The MAX31826 measures temperature at 12 bit resolution as fast as the DS1825's lowest resolution (and always uses 12-bit resolution). On the other hand it has no temperature thresholds or alarm function.