The Fluke Model 22 40 C Data Logger in its basic form is a processor and recorder which, through the use of optional plug-in modules, is expandable into a user-designed data acquisition system capable of servicing up to 1000 channels of guarded analog data. The basic unit is contained within a mechanical housing and consists of a front-mounted control panel, a digital display, a digital printer, a power supply, the control logic required to interface the basic unit with a full complement of options, an A/D converter and guard crossing, and a series of pcb and module slots designed to accommodate a number of plug-in options. To form an operational data acquisition system, the 22 40 C must be equipped with at least one each of the two following options: a scanner (Option -05 , -06 or -33) and a scanner input connector (Option -03, -07 or -08). 1-3· Front Panel 1-4. The front panel of the 22 40 C features al1 of the controls necessary to operate the unit with a full complement of options. The controls consist pr imarily of pushbutton switches which are separated into 10 unique groups. Five groups perf orm control functions and five groups are dedicated to programming the 22 40 C„ The control group includes: Power, OUTPUT CONTROL, PROGRAM LIST, SCAN CONTROL, and DISPLAY CONTROL. The program groups include: TIME ENTRY, SCAN FORMAT, PROGRAMMING (CHANNEL , AVERAGING, mx + b, and LIMITS), ADVANCE ADDRESS, and DATA ENTRY. 1-5. The 2240C is energized when the power switch is set to POWER ON or KEYBOARD PROGRAM DISABLE. In the POWER ON position, all control functions are enabled. In KEYBOARD PROGRAM DISABLE, all control functions except OUTPUT CONTROL and SCAN CONTROL are enabled. If channel programming data has been previously entered into memory (via the front panel programming switches), any one of four unique scan modes (single, in terv al, monitor, or continuous) can be started and/or stopped using the SCAN CONTROL switches. During a scan sequence, analog data present at program-selected channe1s is measur ed and displayed at the 22 40 C front panel. When desired, this measurement data can also be recorded on either the internal pri nter and/or an external recording device. The recording devices to be used and the type of data to be recorded are selected by the OUTPUT CONTROL and the SCAN CONTROL switch groups. While measurement data is being recorded, alternate forms of data (date and time or single channels) can be selected and displayed by depressing the appropriate switches in the DISPLAY C0NTR OL group. Similarly, an alternate form of data, program list, can be recorded when the SCAN CONTR OL switches are reset and the internal printer is ena bled to print al 1 data. When the PROGRAM LIST switch is depressed under these conditions, the contents of the keyboardcontrolled program memory are recorded on the internal printer» If a Remote Program Option (-15 or -17) is installed, a program list can be requested and output via the option.