Chemglass AF-0304 User Manual
Page 22
5.3. Changing Operating Line Voltage
5.4. Set Point Hysteresis
20
The operating voltage for instruments can be changed in
the field by changing the connection across four pads on
one of the circuit boards. For access to these pads,
remove 2 screws in rear of the cylindrical outer cover.
Slide the cover back, completely away from the circuit
boards. Locate the four pads on the edge of the circuit
board where the power cord comes to the circuit board.
Instruments set for operation at 115 VAC have jumpers
connecting the outside pairs of the four pads. Instruments
set for operation at 220 VAC have jumpers connecting the
inside pair of the four pads. See illustration below.
In some vacuum or pressure control systems the system
performance can be improved and “chatter” around the
set point eliminated if some amount of hysteresis is
added to the set point control circuit.
Clip the jumpers close to the pads and install new
jumper(s) to change to the desired configuration.