Siemens SITRANS P Manual de usuario descargar pdf (Pagina 112)

On-Line Operation UMSITRPDS3-1

November 2010

6-14

6.2.8 Pushbutton and Function Disable

Mode 10 is used to disable some or all magnetic pushbutton functions. In addition, a write protect

function can be activated to prevent changing of saved parameters. There are five options as shown in

Table 6.3.

TABLE 6-3 Pushbutton and Function Disable Options

Symbol Explanation

no symbol No disable.

LA Input pushbuttons disabled. Operation via HART is enabled.

LO Zero can be set; all other functions are disabled. Operation via HART is enabled.

LS Only zero and full scale can be set (see Section 6.3); all other functions are disabled.

Operation via HART is enabled.

L Write protect enabled. Operation by HART disabled.

LL is another pushbutton disable that is available in HART; see Section 6.4.9. The disable option symbol

will appear in the lower left quadrant of the digital display. To cancel a disable option, see Section 6.2.1.

To select a pushbutton or function disable option:

1. If LO or LS is to be selected, first press the M pushbutton to go to mode 13. Select either Current in

mA or Current in %. Otherwise, a change in the output variable will not be detected when an arrow

pushbutton is pressed.

2. Press the M pushbutton to go the mode 10. Select a disable option by pressing either arrow

pushbutton.

3. Press the M pushbutton to save the selection.

Note

When a transmitter is delivered without a display, disable option LS is active. If

the transmitter is to be permanently operated without a display, be sure option LS

remains active.

6.2.9 Flow Measurement (Differential Pressure only)

Select the characteristic of the output current as follows:

• Linear - proportional to the differential pressure

• Square Root - proportional to the flow

Below the switch point of the square root function, output current can have a linear characteristic (SrLin),

rise slowly to 0.6% and then increase linearly (SrLi2), or stay at 4 mA (SroFF). See Figure 6-2 for the

three characteristics.

To select the characteristics:

1. Press the M pushbutton to enable mode 11.

2. Press either arrow pushbutton to select the desired characteristic.

3. Press the M pushbutton to save the selection.

4. Press the M pushbutton to enable mode 12.

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Siemens SITRANS P Manual de usuario Pagina 112