Burkert Type 8620 - Manual (Page 66)

mxCONTROL Type 8620
Page 66
Calibration Mode “1-point”
This calibration mode can be used for the calibration
of 4-20mA input signals from e.g.
• Redox Transmitters
• pH-Transmitters
This mode of calibration needs one buffer solution to
receive the new straight calibration line.
Take care for the dependence of temperature
of the buffer solution/pH-measurement.
Usually it is mentioned on the buffer bottles.
→ Hold the current PV during the calibration procedure: Yes or No
(Default: Yes).
Hold Function – for calibration without interrupting the process:
it holds the PV constant during the whole calibration procedure.
Therefor the current PV is used when starting the calibration
procedure with confirming “Next Step”.
→ Proceed with “Next Step”, press key “OK”
→ Then rinse/clean the electrode as requested, after that press key “OK”
→ Scroll to “1stPoint”, press key “INPUT”.
→ Put
the electrode into buffer solution and input the value of this buffer
solution (care for temperature dependence), confirm with “OK”.
→ Wait until the measured PV has a steady value, then
→ Proceed
with “Next Step”, press key “OK”
The controller measures the current PV of the buffer solution and the corres-
ponding current I_1…
… and calculates Offset and Slope values.
→ Rinse/clean the electrode again before putting back into process fluid.
→ Finish calibration and the Hold Function of PV with “End”, press key “OK”
Calibration Mode “2-point”
This calibration mode can be used for the
calibration of 4-20mA input signals from e.g.
• pH-Transmitters
This mode of calibration needs two buffer solutions
to receive the new straight calibration line.
Take care for the dependence of tempe-
rature of the buffer solution/ pH-measure-
ment. Usually it is mentioned on the
buffer bottles.