Fluke Biomedical 942A-200L-M4 - Manual (Page 47)

Operation
Operational Modes
3
3-7
In addition, the front panel of the UDR is provided with an alternate action Gross/SCA mode select switch.
The UDR is normally is the Gross mode of operation. When the Gross/SCA mode switch on the UDR
front panel is pressed, the UDR operating mode is changed from Gross to SCA, and a green LED built
into the Gross/SCA switch illuminates. Pressing the switch again returns the UDR to the Gross mode, and
turns the green SCA mode LED indicator off. Operation of the UDR in Gross and SCAA mode are
summarized below:
Function: Mode:
Gross
SCA
Digital Display:
High Alarm Trip:
Warn Alarm Trip:
Analog Output:
Range alarm:
Fail Alarm Trip:
Bar graph Display: Gross CPM
Gross CPM
Gross CPM
Gross CPM
Gross CPM
Gross CPM
Gross CPM SCA CPM
SCA CPM
SCA CPM
Gross CPM
Gross CPM
Gross CPM
Gross CPM
The –M1 suffix on the Model 942-200-90-M1 SCA indicates the standard SCA circuit board has been
modified for this application. The –M1 modification consists of adding a jumper wire from the internal DIP
switch, SW1-5, pin 12, to the W1-2 jumper on the SCA board. W1-2 is internally connected to the J2-1 on
the SCA board. As a part of the 942A-200LM4 modifications, J2-1 on the SCA board is wired to the
Normally Open switch contact on the Gross/ SCA switch, SW8-1. The common contact, SW8-2, is wired
to the SCA J2-2 connector, grounding the SCA select input when SW8 is pressed. A LED mounted
internally in SW8 is powered from the +15 VDC power supply available on SCA J3-41 (Ground) and J3-
45 (+15VDC). A 511-ohm, 0.5-watt current limiting resistor is wired in series with the LED. The resistor is
physically mounted on the body of SW8, between SW8-4 (+15 VDC, from SCA J3-45) and SW8-+(LED +
terminal). The LED – terminal is wired to ground through SCA J3-41. Refer to the modification instruction
942A-200L-M4MS and 942-200-90-M1MS, located in Attachment for further in formation.
The SCA function is not implemented on the Model 942A-200L-M5-M5 UDR.
Alarm Inhibit
Alarms are inhibited in situations where an alarm trip would be meaningless because the UDR is not in a
normal measurement mode (i.e., when the UDR is in the Check Source (jumper selectable) or Calibrate.
During Alarm Inhibit, new alarm trips cannot occur and old alarms cannot be reset. When the inhibit
period is over, alarm trips and resets are enabled again. Alarm inhibit conditions are discussed in the
following paragraphs.
Data Entry Mode
Data Entry Mode is selected by pressing the ENTER pushbutton while the rotary FUNCTION switch is in
a valid setpoint position (see "Parameter Entry" Section 3.11). The selected setpoint is displayed in
exponential format (e.g. 1.00E2) with the left most digit flashing. If the FUNCTION switch is not in a
setpoint position, pressing the ENTER button has no effect. Refer to Table 3-2 for FUNCTION switch
positions.
In the Data Entry Mode, all alarms are active. The bar graph and analog outputs are active. The check
source and alarm acknowledge functions are active.