Dräger PEX 3000 Mode D'emploi page 37

– 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".
– 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.
– Press the (▲+▼) keys to exit the function. The display shows SL once
again.
– Press the ▲ key once to return to measuring mode.
CL – calibrating 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!
– Use the ▲ or ▼ key to navigate until the display shows CL ("Calibrate
Loop").
– Press the (▲+▼) keys. This sets the lower reference point, the display
shows "04" corresponding to 4 mA.
– Read the current on the measuring instrument or on the controller.
– 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.
Dräger PEX 3000
– 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.
– Read the current on the measuring instrument or on the controller.
– Press the ▲ or ▼ key to adjust the current output such that the ammeter
reads a current of 20 mA as accurately as possible (between 19.95 and
20.05 mA). Pressing the keys for a longer period activates the repeat
function.
– Press the (▲+▼) keys. This saves the upper reference point and exits the
function. The display shows CL once again.
– Press the ▲ key twice to return to measuring mode.
CU – setting the sensor current
This function is used to adjust the sensor current if the necessary sensor
current is different from the ex-factory setting. Ex-factory settings are:
Type XTR 0000, XTR 0001, XTR 0090 and XTR 0091:
Type XTR 0010 and XTR 0011:
WARNING
Adjustment of the sensor current must be followed by the re-calibration of the
zero-point and span!
– Navigate using the ▲ or ▼ keys until the display shows CU ("CUrrent") and
confirm by pressing the (▲+▼) keys.
– The display shows the last two digits of the currently adjusted sensor
current, e.g. the display shows "70" for a sensor current of 270 mA.
– Use the ▲ or ▼ key to adjust the sensor current between 240 mA (display
shows "40") and 300 mA (display shows "00") in 1 mA steps. Pressing the
keys for a longer period activates the repeat function.
Operation
255 mA
276 mA