GE DigitalFlow GF868, Service Manual

Page: 14 / 74

Chapter 1. Calibration
4 DigitalFlow™ GS868 Service Manual
1.4 Accessing the Calibration Menu
1. Press the
[CAL]
key to enter the Calibration Program .
2. Press
[Fx]
to calibrate the desired slot. (The option bar will include a slot listing for each installed option card.)
3. Press
[Fx]
to select the desired output.
IMPORTANT:
The procedure for calibrating all the outputs is the same. However, when calibrating a different output, be
sure to reconnect the ammeter to the appropriate pins on terminal block I/O. See Figure 1 on page 2 or
Figure 2 on page 3 for the correct pin numbers.
1.4.1 Calibrating the Low End of the Output Range
1. Press
[F1]
to calibrate the low end of the output range.
2. Press
[F1]
or
[F2]
to adjust the ammeter reading
UP
or
DOWN
, until a 4 mA reading is achieved. If you press
[F3],
Numer,
enter a numeric value for the calibration point and press
[ENT].
3. Press
[F4]
to
STORE
the setting, or press

and
[F1]
to
ABORT
the calibration.
Note:
If the ammeter reading cannot be adjusted within 5.0

A of the 4 mA setting, contact the factory for assistance.
1.4.2 Calibrating the High End of the Output Range
1. Press
[F2]
to calibrate the high end of the output range.
2. Press
[F1]
or
[F2]
to adjust the ammeter reading
UP
or
DOWN
, until a 20 mA reading is achieved. If you press
[F3],
Numer
, enter a numeric value for the calibration point and press
[ENT]
.
Note:
If the ammeter reading cannot be adjusted within 5.0

A of the 20 mA setting, contact the factory for
assistance.
3. Press
[F4]
to
STORE
the setting, or press

and
[F1]
to
ABORT
the calibration.
Note:
Skip the next section if the linearity test will not be performed at this time. Go to Procedure Options on page 5.
1.4.3 Testing the Analog Output Linearity
Note:
If you exited this menu and are returning, follow steps 1 through 3 in
Accessing the Calibration Menu
on page 4.
1. Press
[F3]
to
TEST
the linearity of the currently selected analog output.
2. Check the ammeter reading at the 50% output level.
3. Then, enter a different output level (0-100%) and press
[ENT]
.
4. Check the ammeter reading at this setting and press
[ENT]
when done.
Table 1 on page 5 lists the expected ammeter readings at various % Full Scale settings, for both 4-20 mA and 0-20 mA
scales. Refer to this table to verify the accuracy of the ammeter readings taken above.