Extech BT100

I used this battery capacity tester to measure battery internal resistance and battery voltage of the battery. It has an RS232 connection which connects to the computer via usb. As with the RadioShack Multimeter, the bytes coming from the device had to be decoded. Luckily, this meter had a well-detailed data sheet .

Reading Serial Port and Connecting to DB

Deciphering the protocols was very straight-forward given the sheet. The only tricky part was Byte 6, which delegates the status of the meter. It basically assigns decimal points to the readings and determines to display '-' or 'OL' if needed. After the program for this meter was completed I joined it together with the Radioshack Meter application and prettied up the front end to make it simple for the operator to use.

Aside of reading data coming from both meters, the program writes the recorded values to a SQL database. Writing the values to a database as oppose to a local file allows anyone to be able to look at and query the data on demand without disrupting the software. Moreover, this connectivity allows for user verification via a log-in screen at the beginning of the program. This allows an administrator to grant access only to users trained in the process.

In Action

The video shows some of the programs functionality. If the PDC code scanned is over 2 years old the program alerts the operator with a prompt indicating the battery should be recycled. Otherwise, the operator has to simply scan the serial number, place it on the fixture and look at the screen for the test result.