Dräger PEX 3000 Manual Del Usuario página 31

– The display shows the test gas concentration used during the previous
adjustment in % LEL.
– Use the ▲ or ▼ key to set the concentration of the test gas currently in
use between 20 and 99% LEL in 1% LEL steps (or 0.1% LEL steps
between 2.0 and 9.9% LEL). Pressing the keys for a longer period
activates the repeat function.
2. Press the (▲+▼) keys, apply test gas to the sensor and wait until the
displayed measured value has stabilised (maximum of 3 minutes).
3. Press the (▲+▼) keys to recalculate and save the internal amplification.
4. Press the (▲+▼) keys to display a reference value for the sensor's
sensitivity (constantly amplified bridge signal).
5. Press the (▲+▼) keys to exit the function. The display shows SP once
again.
6. Press the ▲ key twice to return to measuring mode.
4.4 Maintenance menu
To enter the maintenance menu, press the ▼ key for more than 3 seconds until
the display shows "SL" and the point in the bottom right corner flashes to
indicate the maintenance state.
4.4.1 SL – set current output to X mA
This function can be used to set the transmitter's output signals to specific
constant values for test purposes.
This function can trigger alarms at the controller!
1. Navigate using the ▲ or ▼ keys until the display shows SL ("Set Loop") and
confirm by pressing the (▲+▼) keys.
– The current output of the transmitter is set to 4 mA, the display shows
"04".
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2. Use the ▲ or ▼ key to adjust the current output to values between 1 and
22 mA in steps of 1 mA. Pressing the keys for a longer period activates the
repeat function.
3. Press the (▲+▼) keys to exit the function. The display shows SL once
again.
4. Press the ▲ key once to return to measuring mode.
4.4.2 CL – Adjusting the current output
This function can be used to calibrate the transmitter's current output, i.e. a
current of 4 mA corresponds to a display of 0% LEL and a current of 20 mA
corresponds to 100% LEL or 10% LEL. Generally, the output signal can be
measured on the controller side as a voltage drop across the input resistance, if
not the 4 to 20 mA loop has to be disconnected to install an ammeter for this
purpose.
WARNING
If the current loop is disconnected at the transmitter for test purposes, the
explosion protection is interrupted!
1. Use the ▲ or ▼ key to navigate until the display shows CL ("Calibrate
Loop").
2. Press the (▲+▼) keys. This sets the lower reference point, the display
shows "04" corresponding to 4 mA.
3. Read the current on the measuring instrument or on the controller.
4. Press the ▲ or ▼ key to adjust the current output such that the ammeter
reads a current of 4 mA as accurately as possible (between 3.95 and
4.05 mA). Pressing the keys for a longer period activates the repeat
function.
5. Press the (▲+▼) keys. This saves the lower reference point and the menu
switches over to the upper reference point. The display shows "20"
corresponding to 20 mA.
6. Read the current on the measuring instrument or on the controller.
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