Access Lcd Display Circuit; Adjust Scaling; Change Decimal Point; Troubleshooting - Omega FMA1800A User Manual

7.4.1

Access LCD Display Circuit

Carefully remove the LCD from the FMA1700A/1800A 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 FMA1700A/1800A to full
scale flow (5 VDC or 20mA). Maintain full scale flow, and adjust the potentiome-
ter [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
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?
"0"
"3"
"2"
"1"
MAXIMUM SCALABLE DISPLAY READING
16
1999
199.9
19.99
1.999