High Speed Strain Gauge Amplifier/Isolator User Manual

Transcription

1 danntech High Speed Strain Gauge Amplifier/Isolator User Manual Thanks for choosing our product to provide the measurements you require. This device is a complete analogue design to achieve the high speed and sensitivity. High quality, low noise components are used to achieve good stability, repeatability, isolation and lowest noise while providing wide range tareing (zeroing) and flexible measurement span with a fast response. The differential input signals are first protected against EMI and spikes with some filtering to avoid high frequency interference. The next stage is a high accuracy instrumentation amplifier with gain selectable from 2 to 1000 using DIP switches, to suit the various loadcell sensitivities. This front end is designed to produce an internal signal of ±10 V for bi-polar applications or 0-10 V in the case of mono-polar (typically weighing) applications. Fine adjustments to the front end signal can be made using multi-turn trimpots at the bottom front of the unit if necessary, we call these the Front End Zero and Gain trimpots. These trimpots, as well as the excitation voltage adjustment are hidden beneath a decal on the front of the device. After the front end the signal is isolated and then passes on to the Tare and Span (or Output Zero and Span) adjustment stage and then on to the various output stages. Two test voltage terminals (V1 and V2) provide a means to be sure that your selected configuration is optimal. Three DIP switches on the right side of the unit (beneath covering decals) provide selections for: Excitation: 5 V or 10 V. Front End Gain: 1, 11, 50, 98, 495 or 970 Filtering: off (BW >6 khz), 100 Hz and 10 Hz Tare/Zero Adjustment Polarity negative (for applications with a pre-load to be tared/zeroed out) or positive (for applications where there is some pre-stress or when you wish to range a bipolar input e.g. ±10 mv to say 0-10 V) Tare/Zero Value 0 to 9.88 V (using six DIP switches) Output Gain 1, 2, 5 or 7 Output Type 4-20 ma, 0-20 ma, 0-10 V or ±10 V danntech PROCESS INSTRUMENTATION Page 1 of 12

2 Connections Functional Description The basic idea is to produce a useful voltage somewhere between -10 V and +10 V at V1. The settings to do this will depend upon the particular application. In the case of a loadcell the input may be uni-polar for example 0 to 10 mv for the input load range or bi-polar for example ±20 mv for a strain gauge measuring an impact. The desired output tare/zero and output span are then used to setup the desired output which is produced at terminal V2. This can be 0 to 10 V or ±10 V depending upon the output required. The output type is then selected which can be either current, uni-polar voltage or bi-polar voltage. We recommend that if you need to change the configuration from how it is delivered, it is best to calculate the various gains and the output offset/tare required at the different stages before connecting up. Before installing, setup the DIP switches needed and then connect up and apply power. A loadcell/strain gauge simulator (or mv source) is useful to inject the various inputs. Check the setup by measuring the voltages at V1 between terminals 7 V1) and terminals 8 (Screen) or 12 (V-) and then at V2 between terminals 4 (V2) and 5 (Output -). It is important to decide if your application requires tareing (subtracting a pre-load) or a positive offset adjustment (changing a bi-polar input to a uni-polar output). This determines if the output zero is additive or subtractive and must be selected accordingly. These selection DIP switches can be left open if no output offset is required. danntech PROCESS INSTRUMENTATION Page 2 of 12

3 DIP Switch Details Excitation Excitation V V SW1-8 ON OFF Front End Gain Front End Gain SW1-1 SW1-2 SW1-3 SW1-4 SW OFF OFF OFF OFF OFF 10.7 OFF OFF OFF OFF ON 50.4 OFF OFF OFF ON OFF 97.9 OFF OFF ON OFF OFF 495 OFF ON OFF OFF OFF ON OFF OFF OFF OFF Filtering Bandwidth SW1-6 SW1-7 >6 khz OFF OFF 100 Hz ON OFF 10 Hz OFF ON Tare/Zero Adjustment Polarity Negative (for applications with a pre-load to be tared/zeroed out) or positive (for applications where there is some pre-stress or when you wish to range a bipolar input e.g. ±10mV to say 0-10V) Tare/Zero Adjustment Polarity SW2-7 SW2-8 Positive (addition) ON OFF Negative (subtraction) OFF ON danntech PROCESS INSTRUMENTATION Page 3 of 12

4 Tare/Zero Value Tare/Zero Value SW2-1 SW2-2 SW2-3 SW2-4 SW2-5 SW2-6 0 OFF OFF OFF OFF OFF OFF 0.16 ON OFF OFF OFF OFF OFF 0.32 OFF ON OFF OFF OFF OFF 0.63 OFF OFF ON OFF OFF OFF 1.26 OFF OFF OFF ON OFF OFF 2.53 OFF OFF OFF OFF ON OFF OFF OFF OFF OFF OFF ON These Tare /Zero values are additive so that for example if you switch SW2-4 and SW2-6 on then the Tare/Zero values will be 1.26 V V = V Output Gain Output Gain SW3-6 SW3-7 SW3-8 1 ON OFF OFF 2.1 OFF ON OFF 5.0 OFF OFF ON 7.1 OFF OFF OFF Output Type Output Type SW3-1 SW3-2 SW3-3 SW3-4 SW V OFF ON OFF OFF OFF ±10 V OFF OFF ON OFF OFF 4-20 ma ON OFF OFF ON OFF 0-20 ma ON OFF OFF OFF ON danntech PROCESS INSTRUMENTATION Page 4 of 12

5 Configuration Suggestions These are some typical setups for common loadcell/strain gauge sensitivities. [to follow soon] Configuration Examples A detailed walk-though for several example application configurations will be documented here. An on-line Apple Weighing application with a loadcell with a range of 20 kg and a 10 kg pre-load. The Apple weighing range is 2 kg which is ranged to 4 to 20 ma. The maximum weighing time is 200 ms. Using a Loadcell to Measure the Kinetic Energy of a Falling Object. [to follow soon] Frequency/Step Response Examples Various results for a device set up for input = ±400mV; output = 0 to 5 V Step response for square wave input rise time = 40.86µS. Square wave input at 10kHz, ±300mV. Sine wave response at -3dB output = 15kHz. Phase shift at 10kHz = danntech PROCESS INSTRUMENTATION Page 5 of 12

6 Some other Interesting things about our High Speed Strain Gauge Amplifier/Isolator This QR code is on the right side of the product and if you download a barcode reader app for your smartphone and scan in this code you will be taken to the latest version of this user manual on our website. It can also be found by going to: Manual.pdf You can get dual outputs by using the 0 to 10 V output available between terminals 4 (output -) and 5 (V2) as well as the output you have configured between terminals 6 (output +) and terminal 5 (output -). This device can be used for any mv signals where a high impedance (10 MΩ) is required at wide bandwidth. The input filter can be used to reduce higher frequency noise if required. Consult us if you require a very input impedance instrumentation input sales@danntech.com. danntech PROCESS INSTRUMENTATION Page 6 of 12

7 Specifications Loadcell resistance minimum: 250 Ω. Excitation switch selectable: 5.0 V and 10.0 V and trimpot adjustable, current limited. Step response without filter: approximately 40 µs. Filter DIP switch selectable: off, 100 Hz, 10 Hz. Outputs: 0-20 ma, 4-20 ma, 0-10 V, ±10 V. Ultra precision internal voltage references for both input and output circuits. Five wire loadcell connections. Output Zero and Span trim adjustment: via multi-turn trimpots on the front of the unit. Tare adjustment for weighing applications: 0 to 90% of range using DIP switches. Span adjustment for weighing applications: 1, 2, 5, 10 (so 10% input range can be spanned to spanned to full scale output). Loadcell sensitivities: 1 mv/v, 2 mv/v, 3 mv/v, 5 mv/v, 10 mv/v, 15 mv/v, 20 mv/v and higher. Front end gain DIP switch selectable: approximately 2, 10, 50, 100, 500, Front end zero and full scale trim: via multi-turn trimpots on front of unit beneath decal. Output load >2 kω for the voltage output and 500 Ω maximum for the current output. Linearity: better than 0.1% of full scale. Auxiliary supply AC: VAC or VDC, Hz. Auxiliary supply DC: 24 VDC or 12 VDC -5%, +10%. Internal fuse protection and surge and spike protection. Reverse input polarity protection for DC versions. Operating temperature: -10 C to 60 C. 24 hour operational burn-in. Calibration sheet provided for each unit manufactured. Isolation, input to output: 1000 VDC. Isolation power in to input and output: 1000 VDC for DC powered versions and 3750 VAC for Mains powered versions. DIN rail mounting with dimensions 25 x 80 x 85 mm (W x H x D). Weight packaged = 160g, unpackaged = 130g danntech PROCESS INSTRUMENTATION Page 7 of 12

8 Part Numbering Product Description: Part Numbering: HS Strain Gauge Amp [input]/[output] [excitation][aux supply] GB-HS/s-nt/ep s = input signal range: A - ±5 mv B - ±10 mv C - ±20 mv D - ±50 mv E - ±60 mv F - ±100 mv G - ±150 mv H - ±200 mv J - ±120 mv K - ±400 mv P 0-5 mv Q 0-10 mv R 0-20 mv S mv T mv U mv V mv W mv n - output signal type I = current, V = voltage t - output signal range: current (n=i): A = 4-20 ma B = 0-20 ma voltage (n=v): A = 0-10 V B = 0-50 mv C = ±50 mv D = 0-5 V E = ±5 V F = 1-5 V G = ±10 V K = 0-1 V e excitation: Y = V, Z = V p - auxiliary power supply AB = VAC, C= 24 VDC, D= 12 VD Part Numbering Examples: GB-HS/A-VE/ZA GB-HS/S-VA/ZA GB-HS/B-VA/ZC HS Strain Gauge Amp ±5mV(1mV/V)/±5V,Ex=10.00, 230VAC HS Strain Gauge Amp 0-50mV(5mV/V)/0-10V,Ex=10.00, 230VAC HS Strain Gauge Amp ±10mV(1mV/V)/0-10V,Ex=10.00, 24VDC Loadcell Sensitivity and Input Voltage Range: 1 mv/v 2 mv/v 3 mv/v 5 mv/v 10 mv/v 15 mv/v 20 mv/v Excitation 5.00 V 5 mv 10 mv 15 mv 25 mv 50 mv 75 mv 100 mv V 10 mv 20 mv 30 mv 50 mv 100 mv 150 mv 200 mv danntech PROCESS INSTRUMENTATION Page 8 of 12

9 If you have any comments, application examples or suggestions which could improve this User Manual please them to me at User Manual - Comment. danntech Ltd Co. No College Close, Hamble-le-Rice Southampton, Hampshire SO31 4QU United Kingdom Tel: sales@danntech.info Website: danntech cc Reg. No. CK1986/15338/23 P O Box 1023, Fontainebleau Randburg, 2032 South Africa Tel International: Tel National: Fax International: Fax National: sales@danntech.com Websites: Danntech makes no warranty of any kind with regard to this material, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. Danntech shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance or use of this material. This document contains proprietary information, which is protected by copyright. No part of this document may be photocopied, reproduced, or translated into another language without the prior written consent of Danntech. The information in this document is subject to change without notice. Filename: High Speed Strain Gauge Amplifier_Isolator User Manual.docx Date: 28 March 2014 Version: 2.03 danntech PROCESS INSTRUMENTATION Page 9 of 12