2012-025

SILICON DESIGNS, INC ! Capacitive Micromachined ! Nitrogen Damped ! ±4V Differential Output or 0.5V to 4.5V Single Ended Output ! Fully Calibrated ! Low Power Consumption ! -55 to +125EC Operation ! +5V DC Power ! Simple, Four Wire Connection ! Serialized for Traceability ! Responds to DC & AC Acceleration ! Non Standard Ranges Available ! Rugged Black Anodized Aluminum Module Model 2012 ANALOG ACCELEROMETER MODULE ACTUAL SIZE ORDERING INFORMATION Full Scale Acceleration ± 2g ± 5g ± 10 g ± 25 g ± 50 g ±100 g ±200 g ±400 g Model Number 2012-002 2012-005 2012-010 2012-025 2012-050 2012-100 2012-200 2012-400 DESCRIPTION The Model 2012 accelerometer module provides a rugged protective case around an integrated model 1210L accelerometer for measuring accelerations in commercial/industrial environments. It is tailored for zero to medium frequency instrumentation applications. The anodized aluminum case is epoxy sealed and is easily mounted via two #4 (or M3) screws. It is relatively insensitive to temperature changes and gradients. The cable’s shield is electrically connected to the case while the ground (GND) wire is isolated from the case. An optional initial calibration sheet (2012-CAL) and periodic calibration checking are also available. Please refer to the Model 2210 for applications that require a lower output impedance or greater power supply rejection ratio than the Model 2012 provides. OPERATION The Model 2012 accelerometer module produces two analog voltage outputs, AOP & AON, which vary with acceleration as shown in the graph at right. The signal outputs are fully differential about a common mode voltage of ½ VDD (approximately 2.5 volts). At zero acceleration, the output differential voltage is nominally zero volts; at +full scale acceleration, the output differential voltage is +4 volts; at -full scale acceleration the output differential voltage is -4 volts. The sensitive axis is perpendicular to the bottom of the package, with positive acceleration defined as a force pushing on the bottom of the package. SIGNAL DESCRIPTIONS VDD and GND (Power): Red and Black wires respectively. Power (+5 Volts DC) and ground. AOP and AON (Output): Green & white wires respectively. AOP voltage increases (AON decreases) with positive acceleration. At zero acceleration, both outputs are nominally equal to 2.5 volts. The device experiences positive (+1g) acceleration with its lid facing up in the Earth’s gravitational field. Either output can be used individually or the pair can be used differentially. APPLICATIONS VIBRATION MONITORING VIBRATION ANALYSIS MACHINE CONTROL MODAL ANALYSIS ROBOTICS CRASH TESTING INSTRUMENTATION ROTATING MACHINERY SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE Silicon Designs, Inc. ! 1445-NW Mall Street, Issaquah, WA 98027-5344 ! Phone: 425-391-8329 ! Fax: 425-391-0446 web site: www.silicondesigns.com [page 1] Sep 07 Model 2012 Analog Accelerometer Module ABSOLUTE MAXIMUM RATINGS * Case Operating Temperature . . . . . . . . . . . . . . -55 to +125EC Storage Temperature . . . . . . . . . . . . . . . . . . . . -55 to +125EC Acceleration Over-range . . . . . . . . . . . . . . . . 2000g for 0.1 ms Voltage on VDD to GND . . . . . . . . . . . . . . . . . . . . -0.5V to 6.5V Voltage on AOP or AON to GND 1 . . . . . . . -0.5V to VDD+0.5V Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 mW * NOTICE: Stresses above those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only. Functional operation of the device at or above these conditions is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ESD CONSIDERATIONS: The model 2012 accelerometer is a CMOS device subject to damage by large electrostatic discharges. Diode protection is provided on the outputs but care should be exercised during handling of the cable wire ends. Individuals and tools should be grounded before coming in contact with the cable wire ends. PERFORMANCE - By Model: VDD=+5VDC, TC=25EC. 2012-002 2012-005 2012-010 2012-025 2012-050 2012-100 2012-200 2012-400 Units ±5 ±10 ±10 ±25 ±50 ±100 ±200 ±200 g Hz Frequency Response (Nominal, 3 dB) 0 - 300 0 - 400 0 - 600 0 - 1000 0 - 1600 0 - 2000 0 - 2500 0 - 3000 Sensitivity - Differential 2 2000 800 400 160 80 40 20 10 mV/g 13 32 63 158 316 632 1265 2530 µg/(root Hz) Output Noise (differential RMS, typical) 2000 g Max. Mechanical Shock (0.1 ms) MODEL NUMBER Input Range PERFORMANCE - All Models: Unless otherwise specified, VDD=+5VDC, TC=25EC, Differential Mode. PARAMETER Cross Axis Sensitivity Bias Calibration Error 3 Bias Temperature Shift (TC= -55 to +125EC) 3 Scale Factor Calibration Error 3, 4 Scale Factor Temperature Shift (TC= -55 to +125EC) Non-Linearity (-90 to +90% of Full Scale) 3, 4 Power Supply Rejection Ratio Output Impedance Operating Voltage Operating Current 3 -200 -400 3 Min -002 -005 -010 thru -400 -002 & -005 -010 thru -400 Typ 2 2 1 1 100 50 1 +300 0.5 0.7 1.0 25 90 5.0 8 8 Max 3 4 3 2 300 200 2 1.0 1.5 2.0 Units % % of span (ppm of span)/EC % ppm/EC % of span dB -002 thru -100 4.75 5.25 10 V mA grams Mass (not including cable) Cable Mass 25 grams/meter Notes: 1. Voltages on the AOP & AON signal wires may exceed 0.5 volt above or below the supply voltages provided the current is limited to 1 mA. 2. Single ended sensitivity is half of values shown. 3. Tighter tolerances available on special order. 4. 100g versions and above are tested from -65g to +65g. SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE Silicon Designs, Inc. ! 1445-NW Mall Street, Issaquah, WA 98027-5344 ! Phone: 425-391-8329 ! Fax: 425-391-0446 web site: www.silicondesigns.com [page 2] Sep 07 Model 2012 Analog Accelerometer Module CABLE SPECIFICATIONS & LENGTH CONSIDERATIONS The cable consists of four 26 AWG (7x34) silver plated copper wires with PTFE insulation surrounded by a braided shield. The shield jacket is a PTFE tape wrap with a nominal outer diameter of 0.131”. Extending the model 2012's one meter cable is not recommended. If you do decide to connect additional cable, we recommend you check each individual installation for oscillation by tapping the accelerometer and watching the differential output for oscillation in the 20kHz to 50kHz region. If no oscillation is present, then the additional cable length being used is OK for that particular device. CONVERTING THE 2012's DIFFERENTIAL OUTPUT TO SINGLE ENDED C1 = C2 (See below for value calculation) R1, R2, R3 & R4 = 20k to 50k R1 = R3 to within 0.1% for good common mode rejection R2 = R4 to within 0.1% for good common mode rejection R2 / R1 ratio accurate to within 0.1% for gain control R4 / R3 ratio accurate to within 0.1% for gain control To achieve the highest resolution and lowest noise performance from your model 2012 accelerometer module, it should be connected to your voltage measurement instrument in a differential configuration using both the AOP and AON output signals. If your measurement instrument lacks differential input capability or you desire to use a differential input capable instrument in single ended mode, then the circuit above can be used to preserve the low noise performance of the model 2012 while using a single ended type connection. This circuit converts the ± 4 Volt differential output of the model 2012 accelerometer, centered at +2.5 Volts, to a single ended output centered about ground (0.0 Volts). It provides the advantage of low common mode noise by preventing the accelerometer’s ground current from causing an error in the voltage reading. The op-amp should be located as close as possible to your voltage monitoring equipment so that the majority of the signal path is differential. Any noise present along the differential path will affect both wires to the same degree and the op-amp will reject this noise because it is a common mode signal. The op-amp type is not critical; a µA741 or ¼ of a LM124 can be used. Both plus and minus supplies are needed for the op-amp to accommodate the positive and negative swings of the single ended output. The same +5V supply can be used for both the op-amp and the 2012 or a higher voltage positive supply can be used for the op-amp if you need a larger single ended output swing. For this design, always set R1 = R3, R2 = R4 and C1 = C2. The gain of the circuit is then determined by the ratio R2/R1. When R1 = R2 = R3 = R4, the gain equals 1 and the output swing will be ± 4 Volts single ended with respect to ground. To obtain a ± 5 Volt single ended output, set R2/R1 = R4/R3 = 5/4 = 1.25. The single ended output of the op-amp will be centered at ground if R2 and C1 are tied to ground; using some other fixed voltage for this reference will shift the output. The value of the optional capacitors C1 and C2 (C1 = C2) can be selected to roll off the frequency response to the frequency range of interest. The cutoff frequency f0 (-3 dB frequency) for this single order low pass filter is given by: f0 = SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE 1 2π R2 C1 Silicon Designs, Inc. ! 1445-NW Mall Street, Issaquah, WA 98027-5344 ! Phone: 425-391-8329 ! Fax: 425-391-0446 web site: www.silicondesigns.com [page 3] Sep 07