GE DigitalFlow GC868 User manual

GE
Sensing & Inspection Technologies
DigitalFlow™ GC868
Panametrics Gas Clamp-On Ultrasonic Flowmeter
Service Manual (1 and 2-Channel)

GE
Sensing & Inspection Technologies
DigitalFlow™ GC868
Panametrics Gas Clamp-On Ultrasonic Flowmeter
Service Manual (1 and 2-Channel)
910-226SF1
April 2008
The DigitalFlow GC868 is a GE Panametrics product. GE Panametrics has joined other GE high-technology
businesses under a new name—GE Sensing & Inspection Technologies.

iii
April 2008
Warranty Each instrument manufactured by GE Sensing, Inc. is warranted to be
free from defects in material and workmanship. Liability under this
warranty is limited to restoring the instrument to normal operation or
replacing the instrument, at the sole discretion of GE. Fuses and
batteries are specifically excluded from any liability. This warranty is
effective from the date of delivery to the original purchaser. If GE
determines that the equipment was defective, the warranty period is:
•one year for general electronic failures of the instrument
•one year for mechanical failures of the sensor
If GE determines that the equipment was damaged by misuse,
improper installation, the use of unauthorized replacement parts, or
operating conditions outside the guidelines specified by GE, the
repairs are not covered under this warranty.
The warranties set forth herein are exclusive and are in lieu of
all other warranties whether statutory, express or implied
(including warranties of merchantability and fitness for a
particular purpose, and warranties arising from course of
dealing or usage or trade).
Return Policy If a GE Sensing, Inc. instrument malfunctions within the warranty
period, the following procedure must be completed:
1. Notify GE, giving full details of the problem, and provide the model
number and serial number of the instrument. If the nature of the
problem indicates the need for factory service, GE will issue a
RETURN AUTHORIZATION number (RA), and shipping instructions
for the return of the instrument to a service center will be
provided.
2. If GE instructs you to send your instrument to a service center, it
must be shipped prepaid to the authorized repair station indicated
in the shipping instructions.
3. Upon receipt, GE will evaluate the instrument to determine the
cause of the malfunction.
Then, one of the following courses of action will then be taken:
•If the damage is covered under the terms of the warranty, the
instrument will be repaired at no cost to the owner and returned.
•If GE determines that the damage is not covered under the terms
of the warranty, or if the warranty has expired, an estimate for the
cost of the repairs at standard rates will be provided. Upon receipt
of the owner’s approval to proceed, the instrument will be repaired
and returned.

v
April 2008
Table of Contents
Chapter 1: Calibration
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Menu Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Calibrating the Analog Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Accessing the Calibration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Calibrating the Low End
of the Output Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
Calibrating the High End of the Output Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Testing the Analog Output Linearity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
Calibrating the Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Accessing the Calibration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
aLOW Option = [F1]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
aHIGH Option = [F2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
4 mA Option = [F3]. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
20 mA Option = [F4] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8
Calibrating the RTD Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Accessing the Calibration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Probe Option = [F1] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Numer Option = [F2] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-10
Testing the Alarm Relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-11
Accessing the Calibration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-11
Testing the Totalizer/Frequency Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-13
Accessing the Calibration Menu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1-13
Entering Frequency. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-13
Entering Pulse Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
Chapter 2: Error Codes and Screen Messages
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-1
E0: No Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
E1: Low Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
E2: Sound Speed Error . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
E3: Velocity Range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
E4: Signal Quality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
E5: Amplitude Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
E6: Cycle Skip, Accel.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
E7: Analog Out Error. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
E8: Temp In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3
E9: Press In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E10: Special Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E11: Not Used. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E12: Not Used. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E13: Over Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E14: Totals Overflow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E15: Equation Limit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
E16: High Signal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5
Screen Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5

April 2008
vi
Table of Contents (cont.)
Chapter 3: Diagnostics
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Displaying Diagnostic Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Diagnostic Record . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Flowcell Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Gas Problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Pipe Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
Transducer Problems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Chapter 4: Parts Replacement
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1
Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Removing the Printed Circuit Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
Replacing the EPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Installing an Option Card . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Replacing the LCD Display. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Installing the Printed Circuit Board . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7
Spare Parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Appendix A: Service Record
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Data Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-1
Diagnostic Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A-3
Appendix B: Optional Enclosures
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Rack Mount Enclosure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-1
Rack Mount Fuse Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-2
Rack Mount Option Card Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-3
Rack Mount EPROM Replacement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-5
Rack Mount LCD Display Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-6
Rack Mount Printed Circuit Board Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-7
Circuit Board Removal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-7
Circuit Board Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B-8

Chapter 1

Calibration
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Menu Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1
Calibrating the Analog Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Calibrating the Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
Calibrating the RTD Inputs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-9
Testing the Alarm Relays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11
Testing the Totalizer/Frequency Outputs . . . . . . . . . . . . . . . . . . . . . . . . . 1-13

Calibration 1-1
April 2008
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 xis 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.
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 1-15 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.

April 2008
1-2 Calibration
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 μA (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 1-3. Refer to Figure 1-6 on page 1-15.
Figure 1-1: Ammeter Connection (Output A)
Terminal Block I/O (Slot 0)
B
RTN B
SIG A RTN A SIG
41
+
-
Ammeter

Calibration 1-3
April 2008
Calibrating the Analog
Outputs (cont.)
Figure 1-2: Ammeter Connection for Slots 1-6 (Output A)
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. Refer to Figure 1-1 on
page 1-2 or Figure 1-2 above for correct pin
numbers.
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 Æand [F1] to ABORT the
calibration.
Note: If the ammeter reading cannot be adjusted within 5.0 μA of the
4 mA setting, contact the factory for assistance.
Terminal Block (Option Card)
A
SIG
A
RTN
B
SIG
B
RTN
D
SIG
D
RTN
C
SIG
C
RTN
+
-
Ammeter
1
8

April 2008
1-4 Calibration
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 μA of the
20 mA setting, contact the factory for assistance.
3. Press [F4] to STORE the setting, or press Æand [F1] to ABORT the
calibration.
Note: Skip the next section if the linearity test will not be performed
at this time. Proceed to Procedure Options on the next page.
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 1-3.
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 1-1 on page 1-5 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.

Calibration 1-5
April 2008
Calibrating the Analog
Outputs (cont.)
If the linearity test readings are not within 5 μA of the values listed in
Table 1-1 above, check the accuracy and wiring of the ammeter.
Then, repeat the low and high end calibrations. If the analog output
still does not pass the linearity test, contact the factory for assistance.
Procedure Options You have completed calibration of the analog output. Do one of the
following:
•To calibrate or test another output, press [F4] (EXIT) and return to
Step 3 in Accessing the Calibration Menu on page 1-3.
•To calibrate/test additional slots, press [F4] (EXIT) twice and
proceed to the appropriate section.
•To leave the Calibration Menu, press [F4] (EXIT) three times.
Table 1-1: Expected Ammeter Readings
% Full Scale 4-20 mA Scale* 0-20 mA Scale*
0 4.000 0.000
10 5.600 2.000
20 7.200 4.000
30 8.800 6.000
40 10.400 8.000
50 12.000 10.000
60 13.600 12.000
70 15.200 14.000
80 16.800 16.000
90 18.400 18.000
100 20.000 20.000
* All ammeter readings should be ±0.005 mA

April 2008
1-6 Calibration
Calibrating the Analog
Inputs
Analog inputs may be added to the Model GC868 flowmeter by
installing an Analog Inputs Option Card in one (or more) of the six
expansion slots. The option card contains two analog inputs, which
are designated as A and B. Each of the inputs, which may be either a
0/4-20 mA input or an RTD input, must be calibrated at both the zero-
point and full-scale values. After calibrating the inputs, their linearity
should be tested.
Calibration of the analog inputs requires the use of a calibrated
current source. If an independent calibrated current source is not
available, one of the Slot 0 analog outputs may be used for the
calibration. During the analog input calibration, the Slot 0 analog
output will supply the low reference, high reference, 4 mA and 20
mA signals at the appropriate times.
Note: If a Slot 0 analog output is used to calibrate the analog inputs,
make sure that the Slot 0 analog output calibration procedure
has already been completed.
Connect the Slot 0 analog output(s) (or an independent calibrated
current source) to the analog input(s) on the option card, as shown in
Figure 1-3 below. Refer to the menu map in Figure 1-6 on page 1-15
as a guide.
Figure 1-3: Analog Input Calibration Connections
Analog Input Option Card
A
INHI
A
+24V
A
RTN
A
INLO
B
RTN
B
INLO
B
INHI
B
+24V
1
8
RTN
4
Terminal Block I/O (Slot 0)
RTNSIG
BB SIG AA
1

Calibration 1-7
April 2008
Calibrating the Analog
Inputs (cont.)
For this discussion, assume that the option card has been installed in
Slot x.
Note: The zero point of the analog input 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.
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 input.
The procedure for calibrating Input A is identical to that for calibrating
Input B. However, when calibrating Input B, be sure a calibrated
current source is connected to the appropriate pins on the terminal
block. See Figure 1-3 on page 1-6 for the correct pin numbers. To
calibrate a 0/4-20 mA input card, see the section below.
Note: To calibrate an RTD input card, refer to page 1-9.
4. Press [F1]-[F4] to select the reference point to be calibrated.
Do one of the following:
•If you selected [F1] (aLOW), proceed to aLOW Option on the next
page.
•If you selected [F2] (aHIGH), proceed to aHIGH Option on the next
page.
•If you selected [F3] (4 mA), proceed to 4 mA Option on the next
page.
•If you selected [F4] (20 mA), proceed to 20 mA Option on the next
page.

April 2008
1-8 Calibration
aLOW Option = [F1] 1. Enter the low reference value and press the [ENT] key.
2. Press [F1] to store the current low reference value or press [F2] to
cancel the entry. In either case, the ANALOG INPUT prompt will
reappear.
3. Press [F2] to proceed to the next section.
aHIGH Option = [F2] 1. Enter the high reference value and press the [ENT] key.
2. Press [F1] to store the current high reference value or press [F2] to
cancel the entry. In either case, the ANALOG INPUT prompt will
reappear.
3. Proceed to Procedure Options below.
4 mA Option = [F3] 1. Connect the 4 mA current source to the currently selected analog
input, as shown in Figure 1-3 on page 1-6.
2. Press [F1] to store the current 4 mA value or press [F2] to cancel the
entry. In either case, the ANALOG INPUT prompt reappears.
3. Press [F4] to proceed to the next section.
20 mA Option = [F4] 1. Connect the 20 mA current source to the currently selected analog
input, as shown in Figure 1-3 on page 1-6.
2. Press [F1] to store the current 20 mA value or press [F2] to cancel
the entry. In either case, the ANALOG INPUT prompt reappears.
3. Proceed to Procedure Options below.
Procedure Options You have completed calibration of the analog output. Do one of the
following:
•To calibrate another input, return to Step 3 in Accessing the
Calibration Menu on page 1-7.
•To calibrate/test additional slots, press [F4] (EXIT) and proceed to
the appropriate section.
•To leave the Calibration Menu, press [F4] (EXIT) twice.

Calibration 1-9
April 2008
Calibrating the RTD
Inputs
Calibrating an RTD option card involves a different procedure than
for other analog input cards. However, you access the card in the
same manner as other cards.
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.)
If you have installed an RTD option card, the following screen
appears:
The Probe option allows the meter to calculate the temperature vs.
resistance curve, based on input from the RTD in a temperature bath
or from an RTD calibrator. The Numer option forces the user to
calculate and input the curve values numerically.
IMPORTANT: Use only one option for RTD calibration. Do not try
to calibrate with both options.
Probe Option = [F1] 3. Press [F1] to select Input A, or [F2] to select Input B.
Set Point Temperature 4. Press [F1] to enter the set point temperature (formerly known as
the zero point). This temperature should be at the low end of your
expected operating range.
5. Enter the desired set point temperature, and press [ENT].
6. Press [F1] to STORE the entered temperature, or [F2] to ABORT the
calibration. In either case, the screen returns to the ANALOG INPUT
prompt.
Slope Point Temperature 7. Press [F2] to enter the slope point temperature. This temperature
should be as far from your set point as your temperature bath will
allow, within the range -100° to +350°C (-148° to +592°F).
8. Enter the desired slope point temperature, and press [ENT].
9. Press [F1] to STORE the entered temperature, or [F2] to ABORT the
calibration. In either case, the screen returns to the ANALOG INPUT
prompt.
10.Proceed to Procedure Options on the next page.
CALIBRATION Press [F1] to select the Probe
method of calibration, or [F2] to
select the numeric method.
Slot x Inputs
current input selected
RTD CALIBRAT
last option selected
Probe Numer

April 2008
1-10 Calibration
Numer Option = [F2] The Numer option allows the user to calculate the temperature vs.
resistance information. To do this, the user must first collect data
using the RTDs option in the PRINT menu (discussed in Chapter 5 of
the Programming Manual). The RTDs option allows you to know
what point value the GC868 is reading at a given temperature. With
this information, the Numer option enables you to enter the Set
Temperature and the slope of the RTD input in points/degree,
allowing absolute control over RTD calibration. Before attempting
this step, follow the instructions in Chapter 5 of the Programming
Manual (“The RTDs Submenu”) to obtain point values at your set
point and slope point.
1. Press [F1] to select Input A, or [F2] to select Input B.
Set Number 2. Press [F1] to enter the set number (formerly known as the zero
point).
3. Enter the set point temperature, and press [ENT].
4. The program then asks for the set point number. Enter the points
measured at the set temperature, and press [ENT].
Slope Number 5. Press [F2] to enter the slope number. Calculate the slope number
with the formula:
(1-1)
6. Enter the RTD slope number and press [ENT].
Procedure Options You have completed calibration of the RTD input. Do one of the
following:
•To calibrate another input, press [EXIT].
•To calibrate additional slots, press [EXIT] and then [F4] (EXIT) and
proceed to the appropriate section.
•To leave the Calibration Menu, press [F4] (EXIT) twice.
Slope Slope point set point–
slope temp set temp–
------------------------------------------------------=

Calibration 1-11
April 2008
Testing the Alarm Relays Alarm relays may be added to the Model GC868 by installing an
Alarms Option Card in one (or more) of the six expansion slots. Each
option card includes three alarm relays, which are designated as A, B,
and C. To test the alarm relays, connect an ohmmeter to the option
card terminal block as shown in Figure 1-4 below. Refer to the menu
map in Figure 1-6 on page 1-15 as a guide.
Figure 1-4: Typical Ohmmeter Connections
For this discussion, assume that the option card has been installed in
Slot x.
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 [F1]-[F3] to select alarm relay A, B or C, respectively.
Terminal Block (Option Card)
A
COM
A
B
A
NO
C
C
B
B
-
+Ohmmeter
1
9
C
NC
COM
COM
NO
NC
NO
NC

April 2008
1-12 Calibration
Testing the Alarm Relays
(cont.)
Note: The procedure for testing Alarm Relay A is identical to that for
testing Alarm Relays B and C. However, make sure that the
ohmmeter is connected to the desired normally-open or
normally-closed contact of the currently selected relay. See
Figure 1-4 on page 1-11 for the correct pin numbers on the
option card terminal block.
4. Pressing [F1] (CLOSE) should yield an ohmmeter reading of about
zero. Pressing [F2] (OPEN) should yield an infinite ohmmeter
reading.
5. Press [F3] to EXIT.
6. Repeat the above procedure until both the normally-open and
normally-closed contacts for all three alarm relays have been
tested. Then proceed to Procedure Options below.
Procedure Options You have completed testing the alarm relays. Do one of the following:
•To calibrate/test additional slots, press [F4] (EXIT) and proceed to
the appropriate section.
•To leave the Calibration Menu, press [F4] (EXIT) twice.

Calibration 1-13
April 2008
Testing the Totalizer/
Frequency Outputs
Totalizer/frequency outputs may be added to the Model GC868 by
installing a Totalizer/Frequency Option Card in one (or more) of the
six expansion slots. Each option card includes four outputs, which are
designated as A, B, C and D. To test the outputs, connect a frequency
counter to the card’s terminal block as shown in Figure 1-5 below.
Refer to the menu map in Figure 1-6 on page 1-15 as a guide.
Figure 1-5: Frequency Counter Connections
For this discussion, assume that the option card has been installed in
Slot x.
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 [F1]-[F4] to select output A, B, C or D, respectively.
Entering Frequency 4. Enter a new frequency in the range of 1-10,000 Hz and press the
[ENT] key. Verify that the frequency counter reads the correct
value.
Terminal Block (Option Card)
A
NO
A
COM
B
B
D
D
C
C
Frequency
1
8
Counter
IN
COM
COM
NO
COM
NO
COM
NO