GENERAL OPERATING INFORMATION

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1 Fife Corporation P.O. Box 26508, Oklahoma City, OK 73126, USA Phone: / Fax: / fife@fife.com OPERATING MANUAL GENERAL OPERATING INFORMATION General The SDE-30 module is used for evaluating the capacitance difference of the two transmitters of a capacitive sensor. For correct sensor function the strip material must be electrically conductive. Installation The SDE-30 module is located in a separate housing mounted near the sensor. The electrical connection of the sensor electrodes and the SDE-30 module is pre-wired by FIFE. To connect the SDE-30 module to the signal processor refer to the electrical schematics. Maintenance The capacitive center guide sensor is generally maintenance free. Possible functional impairments and the required remedies are explained in the Troubleshooting section of this manual. Functional Description ELECTRICAL CIRCUIT The SDE-30 module provides to each transmitter a stabilized sine-wave oscillation signal and these two signals are out of phase from one another. Additionally there is receiver electrode that compares the amount of oscillation received from each transmitter. If the strip is centered then equal amounts of each transmitter signal are received and they cancel each other. The red-green LED V29 is for indication of the polarity of the received sensor signal. The output signal of the SDE-30 module is 0-10 ma and is connected to terminal X11. This signal is proportional to the strip position in the sensor. If the strip is centered within the sensor, the output signal will be 5 ma. In this case the LED V29 will go out or the color will change over. 1 of

2 BASIC CIRCUIT DIAGRAM Troubleshooting ELECTRICAL FREQUENCY INTERFERENCE FIELDS A capacitive sensor can be disturbed by electrical interference fields. The LED's V20 and V21 are provided for indication of these failures. LED V20 shows spurious signals in a large frequency range and V21 indicates interference near the working frequency of the sensor (50kHz). NOTE: In case of electrical interference the absolute function of the sensor is no longer guaranteed. Remedies Elimination of the interference source Sufficient shielding of the interference source Better ground connection of critical machine units If such interferences are of short duration, the guiding system can be locked by monitoring the signal on terminal X7. ISOLATION MONITORING This function is used for monitoring the isolation between the sensor electrodes and the sensor frame. The isolation resistance of each electrode is measured and a minimum value is formed. This value is compared with a fixed limit value. The LED V32 will light up if the minimum value is below the fixed limit value. The output from terminal X3 would give an indication of this failure. NOTE: In this case the absolute function of the sensor is no longer guaranteed. Remedies Clean the isolators of any electrically conductive contamination Change the isolators 2 of

3 The minimum value is connected to terminal X4 as an analog current signal (0-10 ma). A value of 10 ma indicates an ideal resistance value of infinity. If the value is lower than 2.5 ma the output X3 is switched on and can be monitored as an alarm signal. LINE-BREAK MONITORING A line-break of the cables between the SDE-30 module and the sensor electrodes can be detected by the SDE-30. This function is possible only on the SDE-30 board itself. Therefore the guiding system must be stopped because special testing signals are switched onto the sensor electrodes that will not allow a valid strip center position signal. During the sensor setup procedure a reference value of the electrode capacitance is adjusted. Later on the actual capacitance value is compared to the reference value. The difference of these values can be indicated. Terminal Connections X 1 +12V for jumper to X2 X 2 Input internal pull-up-resistor 2 kω for X3 X 3 Isolator monitoring alarm Ground switching Open Collector X 4 Current signal isolator monitoring 0-10mA 0 ma at short circuit X 5 +12V for jumper to X6 X 6 Input internal pull-up-resistor 2 k Ω for X7 X 7 Interference monitoring alarm Ground switching Open Collector X 8 Shield Housing connection X 9 Shield Cable shield X 10 Shield Jumper to X16, P-GND X 11 Sensor signal 0 10 ma X 12 Power supply voltage +12 V X 13 Power supply voltage -12 V X 14 P-GND X 15 A-GND X 16 P-GND Jumper to X10 X 17 Transmitter-electrode 1 X 18 P-GND X 19 Transmitter-electrode 2 X 20 P-GND X 101 Receiver-electrode BNC-socket Remark The connection between sensor housing, Cable shield, and P-GND must be made on the SDE-30 module. 3 of

4 Indicators V29 Polarity of the sensor signal (red/green) V20 Input interference, large frequency range V21 Input interference, near working frequency V32 Isolator resistance too small V24 Line-break (only if S3 is in Pos. 2 and one of the push buttons S1, S2 or S101 is pressed) Operating Elements S3 Switch for line-break monitoring S1 Together with S3; Test of the cable at X17, X18 S2 Together with S3; Test of the cable at X19, X20 S101 Together with S3; Test of the cable at X101 R61 Trimmer for oscillating frequency adjustment R47 Trimmer for amplitude relation adjustment of the transmitter electrodes R24 Trimmer for capacitance reference value adjustment at X17, X18 R25 Trimmer for capacitance reference value adjustment at X19, X20 R101 Trimmer for capacitance reference value adjustment at X101 Test Points SDE-30A TP 1 Receiver signal; amplified and filtered TP 2 Demodulated Sensor signal TP 3 Unipolar Sensor signal TP 4 A-GND TP 5 P-GND TP 6 Power supply voltage (+12V) TP 7 Power supply voltage (-12V) TP 8 Isolator resistance for terminal X 17 TP 9 Isolator resistance for terminal X 19 TP 10 Isolator resistance for terminal X101 TP 11 Isolator resistance minimum of TP 8, 9, 10 TP 12 Measuring signal for line-break monitoring SDE-30B TP 1 Isolator resistance for terminal X101 TP 2 Receiver signal; amplified and filtered 4 of

5 Connection Data POWER SUPPLY VOLTAGE X 14 P-GND reference potential X 12 +(10-15) V; I < 70 ma X 13 -(10-15) V; I < 50 ma TRANSMITTER ELECTRODES The capacitive load between transmitter electrode and machine frame including cable must not exceed 3 nf. RECEIVER ELECTRODES The capacitive load between receiver electrode and machine frame including cable must not exceed 3 nf. SWITCHING OUTPUTS X 3 U < 24V; I < 55mA; Ground switching X 7 U < 24V; I < 55mA; Ground switching 5 of

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