stirrer speed display, vessel pressure readout, high temperature protection, and motor current readout could be ordered with analog outputs that required an analog to digital conversion board to log these readings into a PC. With the 4848 Controller, all of the expansion modules as well as the primary temperature controller are equipped with bidirectional digital communications [RS- 485] that enable the user to not only log all current reading to a PC, but also to send set points, stirrer speeds, and alarm values from the PC to the 4848 Controller.