Industrologic, Inc. reserves the right to change any product's features, specifications, documentation, warranties, fee schedules, and conditions at any time and without notice.
Industrologic products are provided as printed circuit board level assemblies. Some Industrologic products may include mechanical packaging assessories which are provide for the purchaser's convenience, and are not intended to be final assembly enclosures.
Industrologic products are provided with the understanding that the purchaser will determine fitness for any particular application as well as achieve compliance with any particular specifications or regulations as required or desired for that application.
Industrologic's obligation under this Warranty is limited to replacement with a new or repaired unit to the original purchaser. The unit must be returned, and replacements obtained from Industrologic, Inc. or the Distributor or OEM from whom it was purchased.
This warranty will not apply if, in the judgment of Industrologic, Inc., damage or failure of the product has resulted from accident, alteration, misuse, abuse, connection to or operation with incompatible signals or power sources, or improper installation.
Under no circumstances shall Industrologic, Inc. be liable to purchaser or any third party for any loss of profits or other direct or indirect costs, expenses, losses, or consequential damages arising out of or as a result of any defects in or failure of Industrologic products or any part or parts thereof.
THIS WARRANTY IS IN LIEU OF ANY OTHER WARRANTY, EITHER EXPRESSED OR IMPLIED, AS TO DESCRIPTION, QUALITY, MERCHANTABILITY, FITNESS FOR ANY PARTICULAR PURPOSE OR USE, OR ANY OTHER MATTER.
Products must be returned by original purchaser with a Return Materials Authorization (RMA) number issued by Industrologic, Inc. or the Distributor or OEM from whom it was purchased, authorizing its return. Current repair or replacement fees and procedures will be related during the issue of the RMA number.
Warranty or repair units must be returned with postage and insurance paid by purchaser. Industrologic, Inc. is not responsible for damages or loss during shipment.
Power Supply Requirements:
Operating voltage: 8 to 30 volts DC regulated or unregulated (filtered)
Operating current: 5mA, plus bridge current
Excitation voltage: 5 volts
Bridge type: Full Wheatstone Bridge
The resistance of strain gauges is commonly in the range of 120 to 350 ohms for each element. Resistances that vary greatly from this range or that are not closely matched may make it difficult or impossible to adjust the amplifier offset.
By design, the amplifier chip output voltage swing is limited to the power supply voltage minus one volt. To allow the voltage swing to span the entire range of 0-5 volts when used with data acquisition devices with this range the amplifier chip is powered by the unregulated power supply rather than the on-board +5 volt regulator. (At the same time, this design allows the output voltage to be greater than the range desired at some circuit gains and bridge signal levels.)
If it is neccesary to use only one or two strain gauges, resistors may be used to replace some of the stain gauges, but the values of these resistors must be very close to that of the strain gauges, or it may not be possible to set the offset voltage of the SGAMP-2 to zero.
The manufacturers of strain gauges often provide "bridge completion resistors" for use with their strain gauges, in order to form a Wheatsone bridge made of resistances with close tolerances.
Resistor RG Gain Ohms 50 2000 100 1000 200 500 500 200 1000 100 2000 50
The SGAMP-2 circuit assembly is normally shipped with a filter capacitor (CF) of .0015uf, for a low pass filter frequency of 1061 HZ. The following chart lists some common capacitor values that can be used for CF, along with their associated frequencies.
Capacitor CF Frequency (HZ) pF uF 100000 .1 16 47000 .047 33 33000 .033 48 22000 .022 72 15000 .015 106 10000 .01 159 6800 .0068 234 5600 .0056 284 4700 .0047 338 3300 .0033 482 2700 .0027 589 2200 .0022 723 1800 .0018 884 1500 .0015 1061 1000 .001F 1591 820 1940 680 2340 560 2842 470 3386 330 4822 220 7234 180 8841 150 10,610 120 13,262 100 15,915 47 33,862 39 40,808 33 48,228 22 72,342 15 106,103
Refer to the Analog Devices AMP04 data sheet for detailed information about cicuit gain and filtering.
Since the amplifier chip is powered by the unregulated power supply, the output voltage level can be greater than the range desired at some power supply voltages, circuit gains, and bridge signal levels. The data acquisition device monitoring the amplifier output signal must include protection against overvoltage if the amplifier might be operated in this region.
Analog Device specifies the AMP04 to have a gain range of 1 to 1000, which would be values of 100K ohms to 100 ohms for RG. Since trimmer pots can be adjusted down to zero ohms, using a trimmer pot for RG will allow the resistance of the trimmer to be adjusted below 100 ohms, bringing the gain higher than the maximum of 1000 specified by Analog Devices.
Although Industrologic has observed the SGAMP-2 circuit to work at gains higher than 1000, it is not recommended, because the AMP04 may be operating in an area of degraded performance. To avoid gains this high, adjust the gain trimmer pot used for RG to the fully counter-clockwise position, and then turn it clockwise until the desired gain and circuit operation is reached.
The offset adjustment on the SGAMP-2 will be affected by having an adjustable gain. The two adjustments will be interactive, that is, they may need to be adjusted back and forth a number of times to find the ideal offset voltage related to the gain setting.
For example, if the offset trimmer pot is adjusted for a voltage slightly above zero volts, (which is often the case), increasing the gain with the gain trimmer pot will increase the offset voltage.
Conversely, if the gain setting is reduced, it will be necessary to check the offset voltage to be sure that it is still slightly above zero volts (if this is intended).
end of manual