DS2760(3)

NAME
DS2760, DS2761, DS2762 - High-Precision Li+ Battery Monitor

SYNOPSIS

  Temperature Voltage and Current.

30 [.]XXXXXXXXXXXX[XX][/[ amphours | current | currentbias | lock.[0-1|ALL] | memory | pages/page.[0-1|ALL] | PIO | sensed | temperature | vbias | vis | volt | volthours |
cc | ce | coc | defaultpmod | defaultswen | dc | de | doc | mstr | ov | ps | pmod | swen | uv |
]]

  Thermocouple

30 [.]XXXXXXXXXXXX[XX][/[ temperature | typeX/range_low | typeX/range_high | typeX/temperature ]]

  Weather Station

30 [.]XXXXXXXXXXXX[XX][/[ WS603/temperature | WS603/wind_speed | WS603/direction | WS603/volt |
WS603/LED/status | WS603/LED/control.ALL | WS603/LED/model |
WS603/calibrationwind_speed | WS603/calibration/direction |
WS603/light/intensity | WS603/light/threshold

FAMILY CODE

30

SPECIAL PROPERTIES

  amphours
read-write, floating point
Accumulated amperage read by current sensor. Units are in Amp-hr (Assumes internal 25mOhm resistor). Derived from volthours / Rinternal.
Formally amphours is the integral of current - currentbias over time.

  current
read-only, floating point
Current reading. Units are in Amp (Assumes internal 25 mOhm resistor). Derived from vis / Rinternal.

  currentbias
read-write, floating point
Fixed offset applied to each current measurement. Used in the amphours value. Assumes internal 25mOhm resistor. Units are Amp and range from -.08A to .08A.
Derived from vbias / Rinternal.

  lock.[0-1|ALL]
read-write, yes-no
Lock either of the two eprom pages to prevent further writes. Apparently setting lock is permanent.

  memory
read-write, binary
Access to the full 256 byte memory range. Much of this space is reserved or special use. User space is the page area.
See the DATASHEET for a full memory map.

  pages/pages.[0-1|ALL]
read-write, binary Two 16 byte areas of memory for user application. The lock property can prevent further alteration.
NOTE that the page property is different from the common OWFS implementation in that all of memory is not accessible.

  PIO
write-only, yes-no
Controls the PIO pin allowing external switching.
Writing "1" turns the PIO pin on (conducting). Writing "0" makes the pin non-conducting. The logical state of the voltage can be read with the sensed property. This will reflect the current voltage at the pin, not the value sent to PIO
Note also that PIO will also be altered by the power-status of the DS2670 See the datasheet for details.

  sensed
read-only, yes-no
The logical voltage at the PIO pin. Useful only if the PIO property is set to "0" (non-conducting).
Value will be 0 or 1 depending on the voltage threshold.

  temperature
read-only, floating point
Temperature read by the chip at high resolution (~13 bits). Units are selected from the invoking command line. See owfs(1) or owhttpd(1) for choices. Default is Celsius.
Conversion is continuous.

  vbias
read-write, floating point
Fixed offset applied to each vis measurement. Used for the volthours value. Units are in Volts.
Range -2.0mV to 2.0mV

  vis
read-only, floating point
Current sensor reading (unknown external resistor). Measures the voltage gradient between the Vis pins. Units are in Volts
The vis readings are integrated over time to provide the volthours property.
The current reading is derived from vis assuming the internal 25 mOhm resistor is employed. There is no way to know this through software.

  volt
read-only, floating point
Voltage read at the voltage sensor;. This is separate from the vis voltage that is used for current measurement. Units are Volts
Range is between 0 and 4.75V

  volthours
read-write, floating point
Integral of vis - vbias over time. Units are in volthours

THERMOCOUPLE

  typeX/
directory
Thermocouple circuit using the DS2760 to read the Seebeck voltage and the reference temperature. Since the type interpretation of the values read depends on the type of thermocouple, the correct directory must be chosen. Supported thermocouple types include types B, E, J, K, N, R, S and T.

  typeX/range_low typeX/ranges_high
read-only, flaoting point
The lower and upper temperature supported by this thermocouple (at least by the conversion routines). In the globally chosen temperature units.

  typeX/temperature
read-only, floating point
Thermocouple temperature. Requires a voltage and temperature conversion. Returned in globally chosen temperature units.
Note: there are two types of temperature measurements possible. The temperature value in the main device directory is the reference temperature read at the chip. The typeX/temperature value is at the thermocouple junction, probably remote from the chip.

WEATHER STATION

  WS603
directory
Weather station from AAG electronica that includes temperature, wind speed, wind direction, light sensor and LED lights.

  WS603/temperature
read-only, floating-point
Uses the DS2760 temperature sensor. This is equivalent to the temperature value. Again in the specificed temperature scale, default Celsius.

  WS603/wind_speed
read_only, floating-point
Readings from the anometer, scaled using the WS603/calibration/wind_speed

  WS603/direction
read_only, unsigned integer
Wind direction, using the following table

1   N

2   NNE

3   NE

4   NEE

5   E

6   EES

7   ES

8   ESS

9   S

10  SSW

11  SW

12  SWW

13  W

14  WWN

15  WN

16  WWN

Values are adjusted (internally) by the WS603/calibration/direction property

  WS603/volt
read-only, unsigned integer
Voltage value from the WS603 device. Units and significance is unclear.

  WS603/calibration/wind_speed
read-write, unsigned integer
Value between 1 and 200 for wind speed scaling. Values on of this range are ignored and the default value of 100 used.

  WS603/calibration/direction
read-write, unsigned integer
Adjustment of wind direction. See datasheet.

  WS603/light/intensity
read-only, unsigned integer
Uncalibrated value from an internal light sensor. Used for control of LED display (daytime vs nighttime).

  WS603/light/threshold
read-only, unsigned integer
Threshold for internal light sensor. Used for control of LED display (daytime vs nighttime).

Value is set as value 4 of the array passed to WS603/LED/control

  WS603/LED/status
read-only, unsigned integer
Status of LED lights intensities. See datasheet.

Value is set as values 2 and 3 of the array passed to WS603/LED/control

  WS603/LED/model
read-only, unsigned integer
What factors control LED display. See datasheet.

Value is set as value 1 of the array passed to WS603/LED/control.ALL

  WS603/LED/model
write-only, unsigned integer array of 4 values
Four integers sent to control LED display. All four values must be sent, comma separated.

0   Light mode

1   Light status

2   Light level

3   Light threshold

OBSCURE PROPERTIES

  cc ce coc dc de doc mstr ov pmod swen uv
varies, yes-no
Bit flags corresponding to various battery management functions of the chip. See the DATASHEET for details of the identically named entries.
In general, writing "0" corresponds to a 0 bit value, and non-zero corresponds to a 1 bit value.

  defaultpmod defaultswen
read-write, yes-no
Default power-on state for the corresponding properties.

STANDARD PROPERTIES

ALARMS
None.

DESCRIPTION

  DS2760 DS2761 DS2762
The DS2760 (3) is a class of battery charging controllers. There are minor hardware difference between the DS2760, DS2761 and DS2762 battery chip, but they are indistinguishable to the software.

A number of interesting devices can be built with the DS276x including thermocouples. Support for thermocouples in built into the software, using the embedded thermister as the cold junction temperature.

For an explanation of the differences between the DS276x variants, see Dallas Application Note 221.

ADDRESSING

DATASHEET
http://pdfserv.maxim-ic.com/en/ds/DS2760.pdf
http://pdfserv.maxim-ic.com/en/an/app221.pdf
http://www.aag.com.mx/aagusa/contents/en-us/Description%20of%20WSV3%20Interface%20(1-wire).pdf

SEE ALSO

AVAILABILITY
http://www.owfs.org

AUTHOR
Paul Alfille (paul.alfille@gmail.com)