820i Programmable HMI Indicator/Controller
48
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Calibrate
Performs calibration for the selected point
Temp Zero
Temporarily zeroes the displayed weight of a non-empty scale. After span calibration, the difference between the temp zero and
the previously calibrated zero value is used as an offset.
Millivolts
(or
Counts
)
Toggles between display of captured A/D counts and captured millivolts values; allows entry of calibration values in mV or
counts
To calibrate the indicator using the front panel, do the following:
1. Place the indicator in setup mode (display reads
Scale Configuration
) and remove all weight from the scale platform.
If your test weights require hooks or chains, place the hooks or chains on the scale for zero calibration.
2. With the
SCALES
menu highlighted, press the
down
key, then select the scale to be calibrated. Press
down
again
(
GRADS
parameter highlighted), then press
left
to highlight the
CALIBR
submenu (see
). Press
down
to go
to zero calibration (
WZERO
). See
3. Ensure scale is empty, then press
down
again to show the current WZERO value, then press the
Calibrate
softkey to
calibrate zero. When complete, the new A/D count for the zero calibration is displayed. Press
enter
to save the zero
calibration value and go to the next prompt (
WVAL
).
4. With
WVAL
displayed, press
down
to show the stored calibration weight value. Use the numeric keypad to enter the
actual value of the calibration test weights, then press
enter
to save the value and go to span calibration (
WSPAN
).
5. Place test weights on scale. Press
down
again to show the current WSPAN value, then press the
Calibrate
softkey to
calibrate span. When complete, the new A/D count for the span calibration is displayed. Press
enter
again to save the
span calibration value and go to the next prompt (
WLIN
).
6. Five-point linearization (using the WLIN parameter) provides increased scale accuracy by calibrating the indicator at
up to five additional points between the zero and span calibrations.
Linearization is optional: if you choose not to perform linearization, skip the WLIN parameter; if linearization values
have previously been entered, these values are reset to zero during calibration. To perform linearization, follow the
procedure below:
With
WLIN
displayed, Press
down
to go to the first linearization point (
POINT 1
). Press
down
again to show the weight
value prompt (
WGT 1
), then
down
once more to show the weight value. Place test weights on the scale, then use the
numeric keypad to enter the actual test weight value. Press
enter
to save the value and move to the calibration (
CAL
1
) prompt. Press
down
to show the current calibration value, then press the
Calibrate
softkey to calibrate the
linearization point. When complete, the A/D count for the linear calibration is displayed. Press
enter
again to save the
calibration value and go to the next prompt (
POINT 2
).
Repeat for up to five linearization points. To exit the linearization parameters, press the
up
key to return to WLIN.
7. The optional rezero function is used to remove a calibration offset when hooks or chains are used to hang the test
weights.
The rezero function cannot be used with five-point linear calibration.
• If no other apparatus was used to hang the test weights during calibration, remove the test weights and press
up
to
return to the CALIBR submenu.
• If hooks or chains were used during calibration, remove these and the test weights from the scale. With all weight
removed, go to the REZERO parameter, then press
down
to show the current zero value. Press the
Calibrate
softkey to adjust the zero and span calibration values. Press
enter
or
up
to return to the CALIBR submenu.
8. Press
up
to return to the SCALES menu, or press the
Save and Exit
softkey to exit setup mode.
4.3 Serial Command Calibration
To calibrate the indicator using serial commands, the indicator serial port must be connected to a terminal or personal computer.
See
for serial port pin assignments; see
for more information about using
serial commands.
Once the indicator is connected to the sending device, do the following:
Note
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