Aalborg GFM User Manual
Page 20
16
7.4.1
Access LCD Display Circuit
Carefully remove the LCD from the GFM or panel mounted surface. Remove the
aluminum housing on the side of the connection cable. Slide the LCD assembly
out of the aluminum housing.
7.4.2 Adjust Scaling
Using a digital multimeter connected to either the 0 to 5 VDC or 4 to 20 mA sig-
nal at the 9-pin “D” connector, set the flow rate on the GFM to full scale flow (5
VDC or 20mA). Maintain full scale flow, and adjust the potentiometer [R3] on the
LCD printed circuit board to desired full scale flow reading.
7.4.3 Change Decimal Point
To change the decimal place on the LCD display readout, simply move the
jumper to the appropriate location on the 8-pin header block. The numbers are
printed to the side of the connections. Do not attempt to place more than one
jumper for decimal setting.
JUMPER POSITION
MAXIMUM SCALABLE DISPLAY READING
“0”
1999
“1”
199.9
“2”
19.99
“3”
1.999
8.
TROUBLESHOOTING
8.1
Common Conditions
Your Mass Flow Meter was thoroughly checked at numerous quality control points
during and after manufacturing and assembly operations. It was calibrated
according to your desired flow and pressure conditions for a given gas or a mix-
ture of gases.
It was carefully packed to prevent damage during shipment. Should you feel that
the instrument is not functioning properly please check for the following common
conditions first:
Are all cables connected correctly? Are there any leaks in the installation? Is the
power supply correctly selected according to requirements? When several meters
are used a power supply with appropriate current rating should be selected.
Were the connector pinouts matched properly? When interchanging with other
manufacturers' equipment, cables and connectors must be carefully wired for cor-
rect pin configurations. Is the pressure differential across the instrument sufficient?