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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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7. 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.
8. Press the (▲+▼) keys. This saves the upper reference point and exits the
function. The display shows CL once again.
9. Press the ▲ key twice to return to measuring mode.
4.4.3
CU – Adjust the sensor current
This function is used to adjust the sensor current if the necessary sensor
current is different from the ex-factory adjustment. Ex-factory settings are:
In combination with the sensing head Polytron SE Ex PR / HT ...
DQ:
In combination with the sensing head Polytron SE Ex LC ... DD: 276 mA
WARNING
Adjustment of the sensor current must be followed by the re-calibration of the
zero-point and sensitivity!
1. 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.
2. 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.
3. Press the keys (▲+▼) to select the displayed sensor current as the newly
set sensor current. The value is saved and this function is exited. The
display shows CU once again.
4. Press the ▲ key three times to return to measuring mode.
255 mA
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