You are now ready to begin construction of the X1W-2. Follow these standard construction practices when building the unit.
Where the camera icon appears, clicking on it will open a new page with a picture related to the procedure detailed in the instructions.
If possible, use a temperature-controlled, fine-tipped soldering iron. In any event the iron must be no greater than 25 watts maximum (15 watts is ideal). A good quality 60/40 or 63/37 rosin-core solder is required for construction. To mount the SMD device use solder with a 0.15" diameter. Keep the tip of your soldering iron bright and clean, wiping it frequently on a wet rag or sponge. Make solder joints carefully, but swiftly. Prolonged heat on a PC board pad can be disastrous as it can ruin the board. Two to three seconds should be enough time to apply heat to any joint. Due to the proximity of some of the traces on the PC board, solder bridges are a very distinct possibility. Following the important points above could eliminate several hours of troubleshooting (or worse). This is good practice when working on any kit.
You will need small flush or semi-flush cutting pliers, small-tipped long nosed pliers and a pair
of tweezers. A magnifying glass may prove helpful to identify the values of the small components and
placement of the SMD.
Be sure that you do the following:
♦ Read all pages on construction prior to building your kit.
♦ The square pad or a dot beside the land on the SMDs or regular ICs identifies pin 1.
Integrated circuits are susceptible to static discharge. Observe anti-static precautions when assembling the kit. Never handle the ICs without grounding yourself, the protective foam, and the PCB first. Always touch and hold the foam or carrier first before touching the IC. Always touch and hold the printed circuit board while placing the SMD. Never leave the ICs on anything but the foam or the PCB.
Surface Mount Devices
Installing a SMD is not as difficult as it seems. Follow the steps in the section on installing SMDs, and you will have a neat, professional looking job when done.
External Power or Bus Power?
Before beginning construction, you must decide if you will be using external or 1-Wire® bus power to furnish the required voltage supply to operate the sensors. The T-238 and X1W-1 both supply a regulated +5VDC on one of the unused lines in the RJ11 cable. The following table should serve as a guide as to which you should use. Plan your installation and make the appropriate choices in later assembly steps.
♦ If you have long lines to the sensor board, you may need to use external power for the temperature sensor to avoid a large number of read errors on the sensor.
♦ The DS9097U adapter from Maxim does not offer external power. There is a newer version that does offer external power (which is more expensive). However, the pin-out is not compatible with the standard used by the T-238 or the X1W-1.