Aim tti single power supply pl155 p aim tti pl155 pg the aim tti pl155 p g offers remote control and read back using analog rs232 usb lan lxi interfaces they retain all of the capabilities of the new pl series when under manual control this version is supplied with the gpib interface when working with any particular piece of equipment engineers often require a voltage source variable over only a narrow range set the voltage too high and damage might occur set it too low