Panametrics DigitalFlow GC868, Руководство по обслуживанию, Страница: 10 / 64

Chapter 1. Calibration
1-1 DigitalFlow™ GC868 Service Manual (1 and 2-Channel)
1.1 Introduction
Calibrating the Model GC868’s analog outputs and inputs is explained in this
chapter. In addition, testing the optional totalizer/frequency and alarm relay outputs
is discussed. The following specific topics are included:
• calibrating the built-in Slot 0 analog outputs
• calibrating optional Slot 1 through Slot 6 analog outputs
• calibrating optional Slot 1 through Slot 6 analog inputs
• testing optional Slot 1 through Slot 6 alarm relays
• testing optional Slot 1 through Slot 6 totalizer/frequency outputs.
The Model GC868 electronics console includes six expansion slots for the installation
of option cards. These slots are numbered 1-6, from right to left. In addition, every
Model GC868 flowmeter includes two built-in analog outputs (A and B) at terminal
block I/O , which is designated as Slot 0 .
Note: Convention in this manual identifies any expansion slot as Slot x , where x is a
number from 0-6.
See Chapter 1, Installation , of the Startup Guide for a complete description of the
available option cards and the procedures for wiring them.
1.2 Menu Map
The
Calibration Menu
is accessed by pressing the [CAL] key on the keypad. Use this
menu to calibrate and test the Slot 0 analog outputs, as well as to calibrate and test
any option cards that are installed in the expansion slots. Refer to the menu map in
Figure 1-6 on page 1-12 as a guide in following the calibration instructions.
Note: The same instructions apply to both the 1-Channel and
2-Channel versions of the Model GC868 flowmeter.
The following discussion assumes that the left screen pane is active. If the right
screen pane is active, only the function key designations change. That is, replace
[F1]-[F4] with [F5]-[F8] . Proceed to the appropriate sections of this chapter to
calibrate and test all of the installed inputs and/or outputs.
Note:
While in the
Calibration Menu
, if there is no keypad activity for two minutes,
the Model GC868 will automatically reboot and return to measurement
mode.
1.3 Calibrating the
Analog Outputs
Every Model GC868 flowmeter includes two built-in analog outputs (A and B) at
terminal block I/O , which is designated as Slot 0 . Additional analog outputs may be
added to the Model GC868 by installing an
Analog Outputs Option Card
in one (or
more) of the six expansion slots. Each option card contains four analog outputs,
which are designated as A, B, C and D. Both the zero-point and full-scale values for
each output must be calibrated. After calibrating the outputs, which have a
resolution of 5.0  A (0.03% full scale), their linearity should be tested.
Note:
The zero point of the analog output may be set for either 0 mA or 4 mA.
However, the calibration procedure always uses the 4 mA point, as the meter
will extrapolate from this value to obtain the 0 mA point.
Prepare for the calibration procedure by connecting an ammeter to the desired
analog output of Slot X , as shown in Figure 1-1 below and Figure 1-2 on page 1-2. Refer
to Figure 1-6 on page 1-12.