Transcript
revised 04/08/10
Product Guide: Series III Pump Control Board Set (RoHS)
Description: The Series III Pump Control Board Set provides motor drive and pump control for a wide assortment of pumps from Scientific Systems, Inc. The assembly consists of two circuit boards:
The Microprocessor Control Board provides connections for controlling the pump through an LED keypad, as well as RS‐232 or USB serial communications protocol. It also contains circuitry for pump pressure monitoring and motor stall detection. The Motor Drive Board contains a series of MOSFETs for energizing the pump’s stepper motor and allows for either AC or DC input power. It also provides pump control and output event markers through a series of contact closures.
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Product Guide: Series III Pump Control Board Set (RoHS)
Section 1: Microprocessor Control Board Construction and Operation Figure 1.1 is an overview of the key components and connection points for the Microprocessor Control Board.
Figure 1.1
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Product Guide: Series III Pump Control Board Set (RoHS)
Front Panel Connections: Figure 1.2 details the front panel connector with its associated display panel and ribbon cable.
Figure 1.2
Front Panel Display: The 4‐Digit LED front panel displays pump flow rate, system pressure, and settable upper & lower pressure limits. Display selection is cycled using the MODE key. A lit mL/min LED indicates the current flow rate (mL/min) is displayed. A lit PSI LED indicates the current system pressure (psi) is displayed. A lit Hi‐Pr LED indicates the pump’s upper pressure limit (psi) is displayed. A lit Lo‐Pr LED indicates the pump’s lower pressure limit (psi) is displayed. A lit Fault LED indicates a fault has occurred and the pump has been stopped. A lit Run LED indicates the pump is running.
Front Panel Buttons: (The operation of front panel buttons is controlled by the individual pump’s firmware. The following descriptions are for reference only.) The RUN/STOP button starts and stops the pump. The button increases the set value currently displayed (e.g. flow rate or pressure limit). The button decreases the set value currently displayed (e.g. flow rate or pressure limit). The MODE button cycles the display through available control functions and readings (e.g. flow rate and pressure limits). The PRIME button runs the pump at a preset flow rate for priming the pump. For information regarding pump faults and actions required to resolve faults, please refer to the Troubleshooting Section of this guide.
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Product Guide: Series III Pump Control Board Set (RoHS)
Serial Communication Ports: Communications with a PC is possible either via RJ‐11 RS232 or USB. Note that when the USB port is connected, RS232 communications are disabled. Figure 1.3 indicates proper wiring between the pump’s RJ‐11 port and a typical computer’s DB9 serial port. Note that RX of the PC connects to TX of the pump.
Figure 1.3
Serial Commands: Serial communications protocol is 9600, 8, N, 1. Communications with the SSI pump are event driven. The pump will respond to commands, but will not initiate communications. The SSI pump is a real‐time device, but communications are not. The pump’s primary function is devoted to the operation of the pump mechanism. To assure communications are unaffected, all input commands are buffered and then processed after the real‐time control functions are performed. Hardware handshaking is implemented in the pump’s serial communications interface. The SSI pump also uses a software acknowledgement character of “/” as the end of transmission character for all transmitted responses. For additional information on pump communications and a complete list of commands, please refer to the associated pump manual or contact SSI Engineering. revised 04/08/10
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Product Guide: Series III Pump Control Board Set (RoHS)
Pressure Transducer Connection: The Microprocessor Control Board contains a 50X operational amplifier and 12‐bit A/D converter circuit that may be connected to a piezoelectric pressure transducer for monitoring system pressure. This pressure transducer connects to the board at P6 (see Figure 1.4).
Figure 1.4 The pressure transducer circuit is capable of very precise pressure readings. Pressure accuracy is typically 0.025% of full‐scale pressure. As an example, using a 10,000‐psi transducer, pressure may be monitored to a resolution of 2.5 psi.
Pressure Enable Jumper: If a pressure transducer is present in the pump, the Pressure Enable Jumper (JU1) must be placed in the ON position (see Figure 1.5). If a pressure transducer is not present, the Pressure Enable Jumper (JU1) must be placed in the OFF position (see Figure 1.5).
Figure 1.5
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Product Guide: Series III Pump Control Board Set (RoHS)
Motor Flag Connection: The Motor Flag Assembly is required for normal operation of the pump. This consists of an optical sensor and rotating “flag” arrangement that is used to detect motor faulting. For single‐ piston pumps, this assembly also detects when the piston is in its fully‐extended position causing the pump to enter its rapid‐refill phase. Please refer to the pump’s manual for further details. The Motor Flag Connector should be wired and connected as shown in Figure 1.6.
Figure 1.6
Section 2: Motor Drive Board Construction and Operation Figure 2.1 is an overview of the key components and connection points for the Motor Drive Board. The image part with relationship ID rId14 was not found in the file.
Figure 2.1 revised 04/08/10
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Product Guide: Series III Pump Control Board Set (RoHS)
Power Connector: The Motor Drive Board can accommodate either AC or DC input powering. Figure 2.2 defines the wiring harness configuration required for DC powering. Please consult SSI Engineering before attempting AC powering of the pump.
Figure 2.2 Pin 1 supplies power to the motor drive circuitry. A maximum recommended voltage is +48 VDC, although some pumps operate typically on +36 or +24 VDC. Please consult SSI Engineering before attempting to operate the pump using a voltage greater than +48 VDC. Pin 2 supplies power to the board control circuitry. The board can accept a voltage range of +14.5 to +30 VDC. Pin 4 may be used as an alternate to Pin 1 for DC motor input. Pin 1 isolates power through a diode rectifier; Pin 4 does not. This isolation may be necessary if a single power supply is used to operate more than one device. A recommended mating connector for the Power Connector is AMP #3‐360426‐5.
Fan Connector: The Motor Drive Board can supply output voltage for powering a fan. Figure 2.3 defines the wiring harness configuration for fan powering.
Figure 2.3 Pin 1 provides +12 VDC. Pin 2 provides +5 VDC. Pins 3 & 4 are both DC Common. revised 04/08/10
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Product Guide: Series III Pump Control Board Set (RoHS)
Motor Connector: The 8‐pin Motor Connector provides the A+ / B+ / A‐ / B‐ wiring connection to the pump’s stepper motor. Figure 2.4 defines the wiring harness configuration for powering the pump stepper motor.
Figure 2.4 The Motor Drive Board is designed to provide the optimal current to its associated stepper motor. Please consult SSI Engineering before attempting to use this assembly for powering any motor other than that supplied with the board assembly.
Output Connector: A 4‐pin terminal board connector is provided on the Motor Drive Board to provide event outputs. Their function is determined by the pump’s firmware. The output is produced internally by a reed relay with SPDT contacts (0.25 Amp maximum, 50 VDC maximum, 0.2 Ohm). Figure 2.5 identifies the pin position and nomenclature for the Output Connector.
Figure 2.5 When the pump fault is detected (e.g. sensed pressure exceeding set limits or motor stall), the event markers are triggered. The EVENT 2 terminal is normally CLOSED relative to the EVENT 1 terminal. On fault, this circuit will OPEN. The EVENT 3 terminal is normally OPEN relative to the EVENT 1 terminal. On fault, this circuit will CLOSE. These are general guidelines for this connector. Please see the pump’s Operator’s Manual for more detail. revised 04/08/10
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Product Guide: Series III Pump Control Board Set (RoHS)
Input Connector: A 10‐pin terminal board connector is provided on the Motor Drive Board to provide inputs to the pump. Their function is determined by the pump’s firmware. Figure 2.6 identifies the pin position and nomenclature for the Input Connector.
Figure 2.6 The pump’s motor can be commanded to run or stop from the input connector. Additionally, the pump’s flow rate can be controlled either through varying input voltage or input frequency. Please see the pump’s Operator’s Manual for further detail on use of the Input Connector.
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Product Guide: Series III Pump Control Board Set (RoHS)
Section 3: Troubleshooting Warning: Do not unplug the Motor Connector from the Motor Drive Board while the power in ON. Turn OFF power to the board and wait 5 seconds for the voltage present in the capacitors to dissipate. Failure to follow this procedure will damage the motor drive power handling devices.
Fault Conditions and Causes: If the pump runs for a short time and then stops, or stops unexpectedly, check for fault status from the front panel LEDs. Motor Stall Fault ‐ the Fault LED is illuminated. This indicates the motor has faulted due to insufficient power or overpressure conditions. High Pressure Fault – the Hi‐Pr and Fault LEDs are illuminated. This indicates the system has surpassed the maximum user‐established operating pressure. Low Pressure Fault – the Lo‐Pr and Fault LEDs are illuminated. This indicates the system has surpassed the minimum user‐established operating pressure Press the RUN/STOP key to clear the fault and return the pump to normal operating mode.
Failure Modes: Pump Not Responding to PC Control Ensure the Communications Cable is properly and securely inserted. Note that the USB connection overrides and disables the RS232 connection. If the Front Panel Display operates normally, verify the correct com port is selected on the PC. If the Front Panel Display is unlit or non‐operational, verify voltages on the Power Input Connector. o If input voltage is not present or incorrect, verify power supply connections. o If input voltage is correct, verify test points for +5V, ‐5V, and +12V. Replace circuit board set if voltages are incorrect. Motor Noise, Motor Stall, or Missing Steps at Low Speed This is an indicator of: o Excessive pressure in fluid path o Drive belt is overly tightened o Defective components in motor drive circuit Motor Drive Diagnosis If the front panel and/or serial communications work, but the motor does not run, replace the Motor Drive Board Fuse. At low speed, the motor may continue to run, even with a damaged MOSFET. Run the motor at a high flow rate. If the motor stalls, this indicates damage to a MOSFET or MOSFET driver. Replace the circuit board.
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Product Guide: Series III Pump Control Board Set (RoHS) Flow Rate Problems All pumps are tested at the factory for flow rate accuracy. Inaccuracies in the expected flow rates are normally attributed to deviations from factory test conditions (solvent and/or pressure). Check the inlet fluid path for obstructions and replace inlet filters. Tighten all inlet fittings to prevent intake of air. Note, loose fittings on the inlet to the pump will not leak solvent, but will reduce flow rates. Check the outlet fluid path for obstructions and leaks. Consult the factory if flow rate issues persist. Pressure Monitoring Not Functioning Correctly Verify the pressure transducer jumper JU1 on the Microprocessor Control Board is set to the ON position. Verify the pressure transducer is properly installed in connector P6 on the Microprocessor Control Board and that all transducer wires are fully seated in their connector. If the pump reads the maximum pressure setting, or a fixed non‐zero pressure, the transducer may be damaged. Replace the transducer. If the pump pressure monitoring is functioning, but inaccurate, the Pressure Adjust circuits may require recalibration on the Microprocessor Control Board. Refer to Appendix B of this document for instructions. If pressure monitoring is still incorrect, or if in doubt regarding recalibration, replace the board and transducer with a factory‐matched set. Front Panel Not Functioning Correctly Verify the display cable is properly inserted in the Front Panel Connector on the Microprocessor Control Board. If the front panel is unresponsive and unlit, the EPROM may be improperly aligned in its socket. Refer to Appendix A of this document for instructions. If the front panel is unresponsive and all the LEDs are illuminated, the EPROM may be improperly aligned in its socket. Refer to Appendix A of this document for instructions.
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Product Guide: Series III Pump Control Board Set (RoHS)
Power‐Up Functions: Additional pump features and diagnostic functions can be accessed by holding specific buttons while turning on power to the pump. Figure 3.1 identifies those power‐up functions available through the front panel.
Figure 3.1 Serial Port Loopback Test requires RJ11 connector with Pins 3 & 4 connected, and Pins 2 & 5 connected. Refill Switch Test indicates detection of motor flag. Rotate motor by hand until display changes. This will test that stall fault and fast refill functions are operating properly. Malfunctions are indicated if the display does not change. Motor Stall Detector disables the stall fault triggered when the motor flag is not detected.
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Product Guide: Series III Pump Control Board Set (RoHS)
Microprocessor Control Board Test Points: Figure 3.2 identifies the location of test points on the Microprocessor Control Board.
Figure 3.2
Figure 3.3 identifies the location of test points on the Motor Drive Board.
Figure 3.3 revised 04/08/10
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Product Guide: Series III Pump Control Board Set (RoHS)
MOSFET Tests: A Digital Multi‐Meter (DMM) can be used to quickly verify that no MOSFET damage has occurred. Figure 3.4 indentifies the leads used to check the MOSFETs for damage. Ensure
Power has been removed from the board before performing this test!
Figure 3.4
MOSFETs Q1, Q3, Q6, and Q7 should measure a resistance of ~ 470 between leads 1 & 3.
MOSFETs Q2, Q4, Q5, and Q8 should measure a resistance of ~3M between leads 1 & 3.
All MOSFETs should measure a resistance of ~2.7M between leads 1 & 2.
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Product Guide: Series III Pump Control Board Set (RoHS)
Appendix A: Changing EPROM/Firmware Many of the pump’s operational characteristics are controlled through firmware stored on its EPROM. Upgrades and modifications to a pump’s firmware will be made by changing EPROMs.
Replacement Instructions: 1. Turn power OFF to the pump and unplug the AC cord. 2. Open chassis be removing cover screws. There are normally 5 screws on each side of the cover. 3. The EPROM is located on the Microprocessor Control Board. Figure A.1 identifies its location and orientation.
Figure A.1 4. Using an IC removal tool or suitable device, remove the EPROM from its socket. 5. Insert the new EPROM into its socket. The EPROM “notch” must match the orientation shown on the circuit board silkscreen. All the EPROM leads must align with the socket and be completed seated. 6. Replace the pump’s cover and reconnect AC cord. 7. Follow Head Type power‐up routine when turning power ON.
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Product Guide: Series III Pump Control Board Set (RoHS)
Changing Head Type: Some firmware will allow the pump to be reconfigured for several flow rates through replacing the pump heads and changing the Head Type variable in the firmware. Changing an EPROM will set the pump to its default Head Type. The Head Type must be checked or reset after changing EPROMs. 1. Hold the RUN/STOP button while powering the pump. 2. Use the or buttons to set the Head Type. Figure A.2 lists possible Head Type options available through this power‐up routine.
Figure A.2 3. Press the RUN/STOP button to place the pump in normal operation mode.
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Product Guide: Series III Pump Control Board Set (RoHS)
Appendix B: Transducer Calibration Variations in Pressure transducer output and tolerances of circuit board components require the circuit board to be “matched” to the transducer used. SSI will supply a replacement kit including a Control Board Assemblies matched to a transducer. This calibration can be performed in the field with limited experience and a small number of tools. Calibration is done with voltages present in the pump, so caution is strongly advised to avoid damage or injury. The tools required for calibration include: Digital Multi Meter (DMM), In‐line Pressure Gauge, a Backpressure Device (e.g. Regulator, coil, or column) and a small screwdriver.
Calibration Procedure: 1. Turn power OFF to pump assembly. Connect the pump’s inlet port to the solvent line and connect the pump’s outlet to the in‐line pressure gauge and then to the backpressure device. 2. Verify JU1 is set to the ON position to enable reading of the pressure transducer (see Figure B.1).
Figure B.1 3. Connect a voltmeter to the pressure board with the black lead on TP11 and the read lead on TP12 (see Figure B.2).
Figure B.2 revised 04/08/10
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Product Guide: Series III Pump Control Board Set (RoHS) 4. Apply power to the pump and set the Lower Pressure limit is set to 0 psi and the Upper Pressure Limit is set to the maximum pressure for the pump. 5. Start the pump and prime. Please reference the pump’s Operator’s Manual for the recommended priming procedure. 6. Stop the pump and open its Prime/Purge Valve so that the system pressure reaches atmospheric pressure (0 psi). Adjust the Zero Pressure Adjust potentiometer (VR1) until the voltmeter reads between ‐0.010 and ‐0.020 VDC. Note: The syringe must be removed from the Prime/Purge Valve to attain an accurate zero reading. 7. Close the Prime/Purge Valve. Start the pump. The pump’s flow rate should be set so that the pressure gauge reads near the pump’s maximum pressure limit. If a backpressure regulator is used, set the flow rate to a nominal value, typically 1 mL/min for most applications. 8. Once the gauge pressure approaches the maximum pressure limit and has stabilized, adjust the Max Pressure Adjust potentiometer (VR2) until the pressure on the Front Panel Display matches that on the external gauge. For proper operation of the pump, these two values should be within 100 psi of each other. Closer precision is possible in most circumstances. 9. Stop the pump and wait for system pressure to return to zero. In extreme cases, the Prime/Purge Valve may be very slowly opened to vent the pressure. Caution: Rapid depressurization of the system may damage the pump’s Pulse Dampener or Pressure Transducer. It is recommended to fully open the Prime/Purge Valve only when system pressure is below 500 psi. 10. Verify the voltmeter reading is still in the ‐0.010 to ‐0.020 VDC range. 11. Repeat steps 6 through 10 as necessary until no adjustment to VR1 is required.
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Product Guide: Series III Pump Control Board Set (RoHS)
Jumper Selection for Pressure Transducer Scaling: The Pressure Gain Jumpers (JU2 and JU3) adjust settings to allow for a variety of transducer options. The jumpers affect the gain of the amplifier circuit while the transducer A/D scaling is controlled by the EPROM. Do not make changes to these jumper settings unless transducer calibration cannot be achieved. Figure B.3 illustrates the Pressure Gain Jumpers in the ON position and the jumper setting combinations to be used for each transducer scaling range.
Figure B.3
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