Manuale d’uso / di manutenzione del prodotto CIO-SSH16 del fabbricante Measurement Specialties
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CIO-SSH16 USER’S MANUAL Revision 3 October, 2000.
MEGA -FIFO, the CIO pre fix to da ta ac quisition board m odel num bers, the PCM pre fix to data acquisition boa rd model num bers, PCM-DA S08, PCM-D24C3, PCM-DAC02, PCM-COM422, PCM-COM485, PCM-DMM, P.
23 6.9 NOISE ...................................................... 22 6.8 CURRENT LOOP (4-20 mA) .................................... 22 6.7 ENGINEERING UNITS ........................................ 21 6.6 A/D RESOLUTION & ENGINEERING UNITS ....
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1.0 SOFTWARE INSTALLATION Before installing the board, install and run Ins ta Cal. This package is the installation, calibration and test utility included with y our board . Insta Cal will guide you through switch and jum per settings for your board. Detailed information regarding these settings can be found below.
There are two cables used w ith CIO-SSH16; a signal cable an d a power cable. The power cable (C-PCPOWER-10) is supplied with the CIO-SSH16. The power cable is black w ith tw o white MOLEX con nectors. One end mates w ith the J3 connector on th e SSH16 and the other m ates with an y one of the available PC power expansion plugs inside the PC.
The SSH16 requ ires 1 A mp of +5 vol t pow er. You m ay su pply t his pow er from the PC , as we recomm end, using the cable supplied, or you may use an alternate power supply.
connected. The nomenclatu re on the CIO-SSH16 corresponds to CIO-DAS16 sig nals. 2.4 ANALOG INPUT BOARD SETUP The analog i nput board mu st be confi gured for s ingle- ended inpu t.
3.0 SIGNAL CONNECTION 3.1 CONNECTOR DIAGRAM The CIO-SSH16 in puts are screw terminals w hich w ill accept 12-22 AWG wire. Each chann el has a screw term inal for signal high, signal low and ground. 3.2 ANALOG INPUTS Analog inputs to the CIO-SSH16 may be connected in tw o different configurations.
A floating differ ential hookup is handy when the signal source is floa ting w ith respec t to ground, such as a ba ttery, 4-20 mA transm itter or thermocouple and the lead lengths are long or subject to EMI interference. The floating differential input will reject up to 10V of EMI energy on the signal wires.
A laboratory instrum ent with its ow n wall plug. There are sometim es differences in wall GND between outlets. 7.
4.0 ARCHITECTURE There are two ty pes of functional elem ents on the CIO-SSH16; differential am plifiers and a sam ple & hold chips (LF398). To geth er they provide diff erential inpu t and amplification for up to 16 channels of simultaneous sampling signal conditioning.
level signal to the analog input boards single ended inputs, reducing the im pact of EMI or RFI alon g the sig nal cable betw een the CIO- SSH16 and the analog inpu t board. 4.3 CIO-SSH16 vs. PROGRAMMABLE GAIN A/D BOARDS Having a dedicated differen tial amplif ier for every ch annel produ ces flexible and powerful data acquisition c apability.
Figure 4-5. Input Range Optimization During post-processing analysis, the range w hich provid ed the best reso lution at any point in time is instantly available. The cost of a CIO-DA S16 and CIO-SSH16 is less th an the cost of an A /D board w ith a channel gain queue and far less than alternative sim ultaneous sample & hold schemes.
Figure 4-6. Input Amplifiers with Sample and Hold Chips SSH OUT is synchronized to the analog inpu t boards S&H chip and the channel select MUX. When the analog input board sam ples chann el 0, each of the LF398s on the CIO-S SH16 also sam ples th e sign al on its input.
Figure 4-7. Sample and Hold Timing Diagram Note that Channel 0 of the CIO-SSH16 does not have an LF398 sample and hold chip. That is because there is one sam ple and hold on the analog input board and it serv es as the S&H chip for CIO- SSH16’s chann el 0.
To calculate the effect of the droop rate on the accuracy of y our measu rement, th e range of the signal, the resolution of the A/D converter and the time between HOL D and A/D acquisition are needed.
5.0 SPECIFICATIONS Typical for 25°C unless otherwise specified. Power consumption +5V 1.0A typical, 1.25A max Analog input section Input amplifier type INA110 Number of channels 16 differential Input range ±10V Gains X1, X10, X100, X110, X200, X210, X300, X310, X500, X510, X600, X610, X700, X710, X800, X810 Gain error Gain = 1 0.
Sample / hold section Sample / hold type LF398 Aperture time 250 ns max, 150 ns typical Aperture uncertainty 50 ns typical Acquisition time 10 µ s m ax Temperature coefficient 4 ppm/°C Droop rate ±100µV/ms RMS Noise (10 kHz to 100 kHz) 10µV Current Drive ±5 mA Output coupling DC Output impedance 0.
6.0 ANALOG ELECTRONICS This short intro duction to the analog electronics most often needed by data acquisition board users describes the follo wing: Voltage dividers. Differential vs. Single Ended Inputs. Isolation vs. Common Mode Range Low pass filters for analog and digital inputs.
Figure 6-1. Voltage Divider The object in usin g a voltag e divi der is to ch oose tw o resistors wit h th e proper proportions rel ative to th e full scale of th e analog or digital input an d the m axim um signal voltage. Dropping t he voltag e proportionall y is often called atten uation.
IMPORTANT NOTE: The resistors, R1 and R2, are going to dissipate all the power in the divider circuit accordin g to the equation Cu rrent = Voltage / Resistance. The high er the valu e of the resistance (R1 + R2) the less power dissipated by th e divider circuit.
A sing le ended input has no com mon m ode range because there is only one LOW wire, which is assumed to be at the same level at the signal and at the A/D board. Figure 6-3. Single-Ended Input The maximum difference which may be rejected is the CMR. For exam ple, the CIO- SSH16 has a common mode plu s sign al range of 11.
the designer of the board (or other EE) would be able to tran slate that into a system s specification, most A/D board owners are confused or mislead by such specs. 6.3 COMMON MISUNDERSTANDINGS The CMR specification of a differential input is often confused with an isolation specification, which it is not.
associated with line voltage (60 Hz) would be filtered out but a signal of 25 Hz would be allowed to pass. Also, in a digital circuit, a low pass filter is often used to filter an input from a switch. Figure 6-5. Low pass Filter A low pass filter m ay be constructed from one resistor (R) and one capacitor (C).
Resolution is a measure of the ability to differentiate betw een one voltage and ano ther. Obviou sly , the m ore bits of resolut ion (13 bits = 8192 coun ts) th e more div ision s of full scale. The m ore divisio ns of f ull scale, the higher the resolution of the measurement.
For example, if the CIO-DAS16 board is set up to read 0 to 5 volts, then: 5 volts / 0.02 Amps = 250 Ohm shunt resistor. So a full 20 mA will register 5 volts and 4 mA will register 1 volt.
specify the conditions under which the specification was made. That means the PC, the PC's power supply and the connection to the front end. Put som e very good com ponents on a circuit board and place th at board in a PC and the system w ill be less accurate than the individual com ponents.
6.9.4 SMOOTHING DATA It is not alw ays possible to eliminate all noise, especially w ith very low level sensors, but noi se looks terribl e wh en plotted an d can raise doubts abou t otherw ise ex cellent data. There are two simple ways to eliminate noise from the data: 1.
For your notes. 26.
EC Declaration of Conformity We, Measurement Computing Corp. , declare under sole responsibility that the product: Description Part Number CIO-SSH16 to which this declaration relates, meets the essent.
Measurement Computing Corporation 16 Commerce Boulevard, Middleboro, Massachusetts 02346 (508) 946-5100 Fax: (508) 946-9500 E-mail: info@measurementcomputing.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Measurement Specialties CIO-SSH16 è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Measurement Specialties CIO-SSH16 - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Measurement Specialties CIO-SSH16 imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Measurement Specialties CIO-SSH16 ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Measurement Specialties CIO-SSH16, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Measurement Specialties CIO-SSH16.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Measurement Specialties CIO-SSH16. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Measurement Specialties CIO-SSH16 insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
