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3.1.3.5 Power-Up Tests
Display Software Version Mode: The software version can be displayed during power-up by pressing and holding the RUN/
STOP and the up arrow buttons when the power is switched on. Release the buttons when the display reads “UEr”. The decimal
point number displayed on the display is the software version. To exit this mode, press the RUN/STOP button.
Display Software Checksum Mode: If the pump is operating erratically, there is the possibility that the firmware stored in the
program memory integrated circuit (EPROM) has been corrupted. Each version of firmware has a checksum which is printed on
the EPROM label. The pump cover must be removed to gain access to the EPROM which is located on the pump control board;
therefore, this should be done only by a qualified technician. To verify that the firmware has not been corrupted, do the follow-
ing: The software checksum can be displayed during power-up by pressing and holding the RUN/STOP and the down arrow
buttons when the power is switched on. Release the buttons when the display reads “CHE”. After approximately 25 seconds, the
4-digit hexadecimal checksum will be displayed. To exit this mode, press the RUN/STOP button. If the checksum displayed does
not match the checksum printed on the EPROM’s label, the EPROM must be replaced. Note: If the pump is operating correctly,
the firmware version and checksum can be displayed, then written in the manual for future comparison. This will save time dur-
ing future troubleshooting since the pump cover will not have to be removed to read the EPROM label.
Serial Port Loop Back Test Mode: If an external device will not communicate to the pump via the serial port, the serial port loop
back test can be used to verify that the serial port is functioning properly. During power-up press and hold the up arrow and the
down arrow buttons when the power is switched on, then release the buttons. The display must read “C00” for the first half of the
test to pass. Plug in the serial port loop back plug (a modular plug with pins 2 & 5 jumpered together and pins 3 & 4 jumpered
together.). The display must read “C11” for the second half of the test to pass. To exit this mode, press the RUN/STOP button.
3.2
Rear Panel Remote Input
An RS-232C modular jack is provided on the back panel. A computer, with appropriate software, can be used as a remote control
device for pump operation via this connection.
Note: For external connections and serial communications see Appendix A at the back of this manual.
4.
Theory of Operation
4.1
Mechanical Operation
4.1.1
Liquid System Flow Path
The flow path of the dual head pump starts at the inlet of the pump head, passes through the pump head and the prime/purge
valve, into the pulse damper, then finally through the bulkhead filter and out the front panel of the pump.
4.1.2
Pump Cycle
The pump cycle consists of two phases, the pumping phase and the refill phase.
During the operation of the pump, one pump piston displaces fluid at a constant rate from one head, while the other piston is
refilling the other pump head with fluid. When that piston is finished displacing fluid, the other piston immediately starts. This
results in a constant, stable flow from the pump at high pressure.
Figure 3-2. Dual Head Pump Rear Panel
