The following controls are available on the front panel:
POWER. An on/off toggle switch that applies power to the pump. When the power switch is turned on, the microprocessor performs a self test. During the self test the pressure display will alternately flash BASi and the software version number.
START/STOP. A toggle switch that starts or stops the pump. This control is used to start or stop solvent flow without turning off the main power.
LOCAL/REMOTE. A toggle switch that selects between flow control by the front-panel switches or by a remote computer or optional gradient controller.
MINIMUM. A potentiometer that sets the low-pressure limit (in PSI) for pump operation. It is EXTREMELY IMPORTANT that this limit be set to some reasonable non-zero value (e.g., 200 PSI, as indicated by the asterisk on the instrument) during normal operation. If a fitting develops a leak, or if the mobile-phase reservoir runs dry during unattended operation, the low-pressure cutoff will stop the pump as pressure drops. Proper setting of this control will avoid pump damage.
If the low-pressure limit is reached, the pump will stop and the red LED above the potentiometer will light. After correcting the problem, reset the protective circuitry by cycling the START/STOP toggle switch through STOP and START.
The low-pressure limit is enabled only after pressure exceeds its set value. Thus, you can run the pump with the prime/purge valve open (pressure will be 0 PSI) even though the low-pressure limit is set to 200 PSI. Only after the prime/purge valve is closed, and pressures get above 200 PSI, will a drop in pressure trigger the protective circuitry.
MAXIMUM. A potentiometer that sets the high-pressure limit (in PSI) for pump operation. It is EXTREMELY IMPORTANT that this limit be set to some reasonable value; if a clog develops anywhere in the flow stream between the pump and the detector, the high-pressure cutoff will stop the pump as pressure increases. We suggest setting the cutoff 1000 PSI above your typical operating pressure. A general-purpose setting is 4000 PSI, as indicated by the asterisk on the face of the instrument.
If the high-pressure limit is reached, the pump will stop and the red LED above the potentiometer will light. After correcting the problem, reset the protective circuitry by cycling the START/STOP toggle switch through STOP and START.
FLOW RANGE. A toggle switch that chooses between standard- and micro-flow rates. In the 0-5 mL/min position, the FLOW RATE controls have an imaginary decimal point between the two digits. In the 0-0.5 mL/min position, the flow rate controls have an imaginary decimal point to the left of the digits.
FLOW RATE. These two control switches change the flow rate in conjunction with the FLOW RANGE toggle switch. With the toggle switch in the 0-5 mL/min position, the digits of the control are to be read with an imaginary decimal point between them (Figure 4.1). With the toggle switch in the 0-0.5 mL/min position, the digits are to be read with the decimal point to the left of both digits.
PRIME/PURGE. This valve provides a tap into the solvent flow line between the pulse damper and the injection valve. Suction can be applied here with a syringe to prime the pump, or new mobile phase can be rapidly brought through the pump and pulse damper.
NOTE: Always allow the system pressure to fall below 30 PSI before opening the prime/ purge valve. This will prevent pressure shocks from damaging the column or pulse damper.