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Reference Manual
00809-0100-4697, Rev EA
October 2011
3-5
Rosemount 848T
Monitoring Application with a Single Selection
Example: Average exhaust temperature of gas and turbine where there is a
single alarm level for all inputs.
1. Link the MAI outputs to the ISEL inputs.
2. Place the Multiple Analog Input (MAI) function block in OOS mode
(set MODE_BLK.TARGET to OOS).
3. Set CHANNEL= “channels 1 to 8.” Although the CHANNEL_X
parameters remain writable, CHANNEL_X can only be set = X when
CHANNEL=1.
4. Set L_TYPE to direct or indirect.
5. Set XD_SCALE (transducer measurement scaling) to the appropriate
upper and lower range values, the appropriate sensor units, and
display decimal point.
6. Set OUT_SCALE (MAI output scaling) to the appropriate upper and
lower range values, the appropriate sensor units, and display decimal
point.
7. Place the MAI function block in auto mode.
8. Place the Input Selector (ISEL) function block in OOS mode by
setting MODE_BLK.TARGET to OOS.
9. Set OUT_RANGE to match the OUT_SCALE in the MAI block.
10. Set SELECT_TYPE to the desired function (Maximum Value,
Minimum Value, First Good Value, Midpoint Value, or Average Value).
11. Set the alarm limits and parameters if necessary.
12. Place the ISEL function block in auto mode.
13. Verify that the function blocks are scheduled.
Measuring Temperature Points Individually
Example: Miscellaneous monitoring of temperature in a “close proximity”
where each channel can have different sensor inputs with different units and
there are independent alarm levels for each input.
1. Place the first Analog Input (AI) function block in OOS mode (set
MODE_BLK.TARGET to OOS).
2. Set CHANNEL to the appropriate channel value. Refer to “Alarm
Priority Levels” on page 3-11 for a listing of channel definitions.
3. Set L_TYPE to direct.
4. Set XD_SCALE (transducer measurement scaling) to the appropriate
upper and lower range values, the appropriate sensor units, and
display decimal point.
5. Set OUT_SCALE (AI output scaling) to the appropriate upper and
lower range values, the appropriate sensor units, and display decimal
point.
6. Set the alarm limits and parameters if necessary.
7. Place the AI function block in auto mode.
8. Repeat steps 1 through 7 for each AI function block.
9. Verify that the function blocks are scheduled.
MAI
Function
Block
Out_1
Out_2
Out_3
Out_4
Out_5
Out_6
Out_7
Out_8
ISEL
Function
Block
IN_1
IN_2
IN_3
IN_4
IN_5
IN_6
IN_7
IN_8
Out
Out_D
AI
Function
Block 1
Out
AI
Function
Block 8
Out
Out_D
Out_D