Initial Check
1-Wire Outdoor Temperature/Humidity Sensor Kit

Preliminaries

If you purchased the T-238 and/or the Dallas Semiconductor weather station...

♦ Assemble any 1-Wire® sensors per the instructions that came with them.
♦ Confirm the sensors are operational with the PC software that came with the unit.
♦ Weather station sensors works with PC software.
♦ Assembled and tested the T-238.

In this section you will again check for assembly errors and install the final jumpers and shunts.

Errors take two forms, the kind that damage components and the kind that don’t. Neither is desirable, but the type that damages components will require you to find a replacement part. Before connecting the board for the first time, check the following:

Ok
Procedure
  Polarity of the tantalum capacitor. The negative lead is usually identified with a white stripe and a big minus sign on it. The positive lead is identified on the PC board. Not all the capacitors have the same orientation; double-check them with reference to the PC board silkscreen.
  Polarity of diodes D1 and D2/D3. The band on the diode should align with the extra stripe on the PC board silkscreen.
  NO shunts are installed at JP3 (T1, T2, H).

Cable and Voltage Check

In the following, the unit will be connected to either the T-238, the X1W-1, or the 1-Wire® DS9097U serial adapter. Remember that this is a straight-through cable. Some telephone cables reverse the wires and some do not. In addition, some telephone cord couplers reverse the wires. Find a telephone cable that does not reverse the wires or make your own.

Hold the connectors side-by-side and oriented the same direction (e.g., clip tab down on both connectors). Observing the colored wires check that the same color wire goes to the same position on both connectors.

Ok
Procedure
  Wires are NOT cross-connected.
  Connect the X1W-2 to the 1-Wire® bus.

Observe anything unusual such as components heating up, smoke or smell. If anything unusual appears, disconnect immediately, find and correct the problem before continuing.

Ok
Procedure
  Place the ground lead of your voltmeter on the anode (opposite the banded end) of D3. This is ground reference for all measurements.
  Measure the voltage on the 1-Wire® bus by connecting the other lead of the meter to the cathode of D3. This should be 5 volts, ±0.25V. If not, disconnect and fix the problem before proceeding.

Perform the following step only if you plan on using external power. It is assumed the correct jumper has been installed on the X1W-1 Sensor/Interface board or you are using the T-238. NOTE: External power will not work with the DS9097U 1-Wire® serial adapter.

Ok
Procedure
  Measure the voltage on the external power bus by connecting the positive meter lead to the cathode of D1 (banded end). If not approximately 5 volts, disconnect and fix the problem before proceeding.

Continuing...

Ok
Procedure
  Disconnect the 1-Wire cable.

Jumpers

You will be using clipped leads from previous steps to install the jumpers. As previously discussed, the humidity sensor works best from the external voltage source (if available) and the temperature sensors give best results if powered from the 1-Wire® bus. Review construction notes as required. As you install the jumpers, solder both leads and clip the excess length for each.

Humidity Sensor
Ok
Procedure
  JP2: + to X (External Power) - preferred
OR
  JP2: + to B (1-Wire® Bus Power)

 

Temperature Sensor
Ok
Procedure
  JP1: + to X (External Power)
OR
  JP1: + to B (1-Wire® Bus Power) - preferred

 

Second Temperature Sensor
(Only If Installed)
Ok
Procedure
  JP4: + to X (External Power)
OR
  JP4: + to B (1-Wire® Bus Power) - preferred

Push-On Shunts

The push-on shunts are used to enable/disable the 1-Wire® sensors. The main use of this feature is for sensor setup in the T-238 firmware and trouble-shooting. Install the following jumpers as required:

Ok
Procedure
  Install push-on shunt at JP3-H
  Install push-on shunt at JP3-T1
Only If Second Temperature Sensor Installed
  Install push-on shunt at JP3-T2

Continuing...

Ok
Procedure
  Reconnect the X1W-2 to the 1-Wire bus.

With a voltmeter confirm the following:

Ok
Procedure
  Approximately 5VDC on pin 5 of U3 (the SMD)
  Positive DC voltage at pin 4 of U3 in the range of 1 to 4 volts. This is the DC output of the humidity sensor. Be careful not to slip the probe and short pins.

If you fail to get these voltages, find the problem before proceeding.

If you have the DS9097U serial adaptor (purchased directly from Maxim or AAG), use the appropriate utility (tstfind on Linux, tstfind.exe on Win32), verify that all devices are recognized. The last two digits of the serial number indicate the type of device. The table below gives a list of these numbers, the device they belong to, and what they are used for in the X1W-1/X1W-2. If the utility fails to see the devices, determine the problem before proceeding with the installation.

ID
Device Used For Kit
05
DS2405 Aspirator, rain gauge heater control X1W-1
10
DS18S20 Temperature: outdoor/indoor/soil X1W-1, X1W-2
1D
DS2423 EMP detector, radiation monitor, rain gauge X1W-1
26
DS2438 Humidity, barometric pressure X1W-1, X1W-2

The tstfind and tstfind.exe utilities are available either on TAPR’s web site or N4XI’s.

Ok
Procedure
  1-Wire® utility recognizes all my devices.

 


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