Datasheet

Quick Start
Required Equipment
● MAX31850/MAX31851 EV kit hardware
● Windows XP or Windows 7 PC with a spare USB
port
● USB Port
● Micro-USB cable (included)
● K-type thermocouple (included)
Note: In the following sections, software-related items are
identified by bolding. Text in bold refers to items directly
from the EV kit software. Text in
bold and under lined
refers to items from the Windows operating system.
Procedure
Follow the steps below to get started measuring
tem perature using the device interfaced to a K-type
thermocouple.
1) Connect the included K-type thermocouple to TH1
(thermocouple socket) of the EV kit hardware. One
terminal of the thermocouple is wider than the other,
ensuring proper polarity.
2) Ensure that jumpers/shunts are installed on JP1 –
JP6. JP1 and JP2 should both be either positioned
on the left for parasitic power mode or positioned on
the right to be externally powered. JP3–JP6 jumpers
can be in either position depending on the desired
location address.
3) Set the EV kit hardware on a nonconductive surface
to ensure that nothing on the PCB gets shorted
togeth er.
4) Prior to starting the GUI, connect the EV kit hard-
ware to a PC using the supplied Micro-USB cable,
or equiva lent. The power LED (D20) should be green
and the com LED (D21) should be red and slowly
flash orange.
5) Windows should automatically begin installing the
necessary device driver. The USB interface of the
EV kit hardware is configured as an HID device and
therefore does not require a unique/custom device
driver. Once the driver installation is complete, a
Windows message appears near the System Icon
menu indicating that the hardware is ready to use.
Do not attempt to run the GUI prior to this message.
If you do, you must close the application and restart
it once the driver installation is complete. On some
versions of Windows, Administrator privileges may be
required to install the USB device.
6) Once the device driver installation is complete,
visit www.maximintegrated.com/evkitsoftware to
download the latest version of the EV kit software,
titled MAX31850_51EVKitSetup.ZIP. Save the EV kit
software to a temporary folder.
7) Unzip the .ZIP file and double click the .EXE file to run
the installer. A message box stating The publisher
could not be verified. Are you sure you want to
run this software? may appear. If so, click Yes.
8) Follow the instructions on the installer and once com-
plete, click Finish. The default location of the GUI is
in the program files directory.
9) When the GUI appears, the status bar should display
EV kit hardware Connected in the bottom right
hand corner. The com LED (D21) on the EV kit board
should turn green.
Detailed Description of Software
Software Startup
If the MAX31850/MAX31851 EV kit is connected when
the software is opened, the software first initializes the
hardware to communicate. Then the software searches
for all ROM codes on the bus and lists them in the ROM
Code drop-down lists. If a ROM code is found with the
correct family code (3Bh), the software reads all data from
the device. If the software is started without the hardware
connected, the initialization sequence above is executed
once the EV kit is connected.
Read Data Tab
When the Read Data tab sheet (Figure 1) is selected, a
temperature conversion is performed and the scratchpad
and power-supply mode are read from the device. The
Read Power Mode button executes the Match ROM
(55h) and Read Power Supply (B4h) command and
displays the data in the Power Supply Mode edit field.
The Read Temperature button executes the Match ROM
(55h), Convert T (44h), and Read Scratchpad (BEh)
commands. This reads the Thermocouple Temp, Cold
Junction Temp, Fault Status, and Location Address,
and then the Linearized Temp is calculated. If the
Power Supply Mode is parasite, then a strong pullup
is enabled while the device converts temperature. If a
fault is detected, then the color indicator turns red and
the status bar displays FAULT!. Both buttons match the
ROM code selected in the ROM Code drop-down list. The
Thermocouple Type drop-down list is used to calculate
the linearized temperature and should be changed to
match the hardware thermocouple type. Table 1 lists all
Evaluates:
MAX31850/MAX31851
MAX31850/MAX31851 Evaluation Kit
www.maximintegrated.com
Maxim Integrated │ 3