200/202 Series Flowmeters and Controllers Instruction Manual
EAR99 Technology Subject to Restrictions Contained on the Cover Page
Page 19 of 27
2.7.3.
Operation with an External Sensor (External Input)
In some instances, it might be desirable to use an external sensor to provide process information to the
control circuitry in a Hastings flow instrument. For example, you might want to control the pressure in a
vacuum system by adjusting the rate at which the system is backfilled with a gas. Hastings flow controllers
have provision for accepting a 0
–
5 VDC output from an external sensor at pin 13 of the DA-15 (15 Volt), Pin
1 of the DE-9 (24 Volt) connector.
2.7.3.1. 15 Volt Units
To activate this feature, the cover of the
HFC must be removed to gain access to the
electronics card and move a jumper. For
the 15 Volt units, J6 is located on the left
side of the PCB between the span
potentiometer (R7) and the large D
connector (J1). In the normal operating
mode, the jumper covers the left two pins.
To select an external sensor input, move
the jumper to the right two pins. This
swaps the flow input to the controller
circuit from the flow meter output to pin
13 of the “DA
-15
”
connector.
2.7.3.2. 24 Volt Units
For the 24 Volt units J8 is a six-pin jumper
block located down and to the right from
the DC-DC converter. There are three
jumpers installed horizontally. The middle
jumper ties the flow output to the valve
control circuit and the top jumper ties Pin
1 of the DE-9 connector to the 5 volt
reference voltage circuit. Remove both of
the upper two jumpers and reinstall one
jumper vertically between the top two pins
on the right side (see diagram below). This
will tie Pin 1 of the DE-9 connector to the
valve control circuit and allow the
controller to maintain the external process
variable equal to the desired setpoint. The
5 Volt reference is not available in this
configuration.
J8
J6
J15