DigitalFlow™ GF868 Panametrics Ultrasonic Flowmeter for Flare Gas

Date: Aug 19, 2025 Views: 4594

　　Calibrating the Analog Inputs

　　Analog inputs may be added to the Model GF868 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 zeropoint 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.

　　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.

　　Analog Inputs Option Card (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 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 the previous page 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.

　　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 the previous page.

　　• To calibrate/test additional slots, press [F4] (EXIT) and proceed to the appropriate section.

　　• To leave the Calibration Menu, press [F4] (EXIT) twice

GF868man.pdf

RELATED ARTICLE