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DAQ-12
Data Acquisition Adapter
For 16 bit ISA compatible machines
Users Manual
INTERFACE CARDS FOR PERSONAL COMPUTERS
OMEGA ENGINEERING, INC. TEL: (203) 359-1660
One Omega Drive FAX: (203) 359-7700
P.O. Box 4047 Toll free: 1-800-826-6342
Stamford, CT 06907-4047 E-mail: das@omega.com
http://www.dasieee.com
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WARRANTY/DISCLAIMER OMEGA ENGINEERING, INC., warrants this unit to be free of defects in materials and workmanship for a period of 13 months from the date of purchase. OMEGA warranty adds an additional one (1) month grace period to the normal one (1) year product warranty to cover shipping and handling time. This ensures that OMEGA’s customers receive maximum coverage on each product. If the unit should malfunction, it must be returned to the factory for evaluation. OMEGA’s Customer Service D
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Declaration of Conformity Manufacturer's Name: Omega Engineering, Inc. Manufacturer’s Address: One Omega Drive Stamford, CT 06907-0047 Application of Council Directive: 89/336/EEC Standards to which Conformity is Declared: * EN50081-2 (EN55022, EN60555-2, EN60555-3) * EN50082-1 (IEC 801-2, IEC 801-3, & IEC 801-4) Type of Equipment: Information Technology Equipment Equipment Class: Light Industrial Equipment Product Name: ISA Data Acquisition Card Model Number : DAQ-12 DAQ-12 Users
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OMEGAnet® On-line Service: Internet e-mail: http://www.omega.com info@omega.com Servicing North America: USA: One Omega Drive, Box 4047 E-mail: info@omega.com ISO 9001 Certified Stamford, CT 06907-0047 Tel: (203) 359-1660 FAX: (203) 359-7700 Canada: 976 Bergar E-mail: info@omega.com Laval (Quebec) H7L 5A1 Tel: (514) 856-6928 FAX: (514) 856-6886 For immediate technical or application assistance: SM USA and Canada: Sales Service: 1-800-826-63
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United Kingdom: One Omega Drive, River Bend Technology Drive ISO 9002 Certified Northbank, Irlam, Manchester M44 5EX, England Tel: 44 (161) 777-6611 FAX: 44 (161) 777-6622 Toll Free in England: 0800-488-488 E-mail: info@omega.co.uk It is the policy of OMEGA to comply with all worldwide safety and EMC/EMI regulations that apply. OMEGA is constantly pursuing certification of it’s products to the European New Approach Directives. OMEGA will add the CE mark to every appropriate device upon cert
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Table of Contents 1. Introduction ......................................................... 8 1.1 Installation ........................................................ 8 1.2 DAQ-12 Specifications ............................................. 9 2. Circuit Board Description and Configuration .............. 10 2.1 Analog to Digital Converter ...................................... 10 2.2 Digital to Analog Converters ..................................... 14 2.3 Digital Input/Output ...........
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List of Figures and Tables Figure 2-1. Jumper J1 Configuration ............................................. 10 Figure 2-2. Jumper J7 Configuration ............................................. 11 Figure 2-3. Jumper J6 Configuration ............................................. 13 Figure 2-4. Jumper J4 Configuration ............................................. 14 Figure 2-5. I/O Base Address Selection .......................................... 16 Figure 2-6. Jumper J3 Configuration
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1. Introduction The DAQ-12 is a high speed data acquisition adapter for IBM AT and compatible machines offering eight differential analog input channels with 16-bit resolution, two analog output channels with 12-bit resolution and four digital input/output lines. Other features of the DAQ-12 include: Analog to Digital Converter 200 KHz maximum sampling rate Bipolar input ranges from ±10mV to ±10 volts Unipolar input ranges from 20mV to 10 volts Programmable gain selection Two DMA chan
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1.2 DAQ-12 Specifications Bus Interface: ISA 16-bit I/O Address Range: 0000H - FFFFH Interrupt Levels: IRQ 2, 3, 4. 5, 6, 7, 10, 11, 12, 14, 15 DMA Levels: DRQ 5, 6, 7 DACK 5, 6, 7 Power Requirements: Power Supply I(t) I(ms) -5 volts --- --- +5 volts 1069.0 mA 1204.9mA -12 volts --- --- +12 volts 374.9 mA 491.4mA I(t) = Typical Current / I(ms) = Maximum Statisical Current DAQ-12 Users Manual
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2. Circuit Board Description and Configuration The base address of the DAQ-12 is selected using switches SW1 and SW2. The operating mode of the DAQ-12 is controlled by jumpers J1 through J7, while DMA and interrupt selections are set with jumpers J8 through J11. Connections to external equipment are made through the high density 62-pin connector CN1. 2.1 Analog to Digital Converter The analog to digital (A/D) section of the DAQ-12 accepts up to 8 differential or 16 single ended inputs from t
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The amplifier stage of the A/D converter circuit performs two functions: (1) amplifies low level input signals and (2) converts this input signal into a voltage range acceptable to the A/D converter. Seven gain levels are software selectable for the amplifier stage of the A/D circuit. To support high level input signals, the DAQ-12 provides input gain selections of 1, 2, 4 and 8. For signals requiring greater amplification, the DAQ-12 provides input gains of 1, 10, 100 and 500. Th
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Table 2-1 details the available gain settings and resulting input ranges for the various input configurations. Note that the 'gain byte' field in Table 2-1 is the value written to the DAQ-12's gain control register. (* indicates unipolar mode not available with gain of ½ ). Maximum Input Voltage Amplifier Gain Byte (HEX) J7 Unipolar / Bipolar Gain --- --- +10/±5 1 1-2 00 +1/±0.5 10 1-2 01 +0.1/±0.05 100 1-2 02 +0.02/±0.01 500 1-2 03 +10/±5 1 1-2 80 +5/±2.5 2 1-2 81 +2.5/±1.2
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The final stage of the A/D converter circuit is the A/D converter IC. The converter must be configured for unipolar or bipolar input voltages as shown in Figure 2-3. When configured for unipolar operation, the analog input multiplied by the gain setting must be in the range of 0 volts (analog ground) to +10 volts. When configured for bipolar operation, the analog input multiplied by the gain setting must be in the range of -5 volts to +5 volts. J6 J6 4 5 6 4 5 6 1
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Voltage Unipolar Bipolar Code Code -5 n/a 1111 1000 0000 0000 -2.5 n/a 1111 1100 0000 0000 0 0000 0000 0000 0000 0000 0000 0000 0000 2.5 0000 0100 0000 0000 0000 0100 0000 0000 5 0000 1000 0000 0000 0000 0111 1111 1111 10 0000 1111 1111 1111 n/a Table 2-2. A/D Conversion Format Examples NOTE: The 'voltage' column is the voltage applied to the A/D converter. This voltage is equivalent to the input voltage multiplied by the amplifier gain. 2.2 Digital to Analog Conver
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The D/A converter channels may also be operated in unipolar mode: 0 to +5 volts, or bipolar mode: -5 to +5 volts. The output mode is selected using jumper J5 as shown in Figure 2-5. In addition, a gain selection jumper is provided to select an output gain of 1 or 2. When using an external voltage reference, this gain can be used to amplify the D/A output for small reference voltages. WARNING: When the internal voltage reference is used,the D/A gain MUST be set to the gain = 1 position. 5 6
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2.3 Digital Input/Output The DAQ-12 offers four bits of digital output and four bits of digital input for control/monitoring of external digital devices. The four digital output lines are LS TTL compatible and will initialize low (0 volts) on power-up. The four digital inputs are also LS TTL compatible. There is no termination provided on the digital input lines and a read of an unused digital input will result in an indeterminate value. 2.4 Base Address The DAQ-12 uses 16 consecutive I/O addr
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2.5 Clock Selection The DAQ-12 is equipped with a programmable clock circuit to produce data sampling rates independent from the clock rate of the host computer. An onboard 8254 programmable interval timer, with a 10 MHz clock input and either two or three cascaded 16-bit timers, provides the sampling rate. This enables the sampling rate to be adjusted from 5 us between samples to almost a year between samples, in as small as 100ns increments. The DAQ-12's sampling rate can also be generated
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2.5.1 Internal Clock Sampling rates for the internal clock can be calculated using the following equation: t = 100ns * [N1*N2] or f = 10MHz / [N1*N2] where N1 is the low 16-bits of the clock divider and N2 is the high 16-bits of the clock divider. The following criteria must be met when selecting values for N1 and N2: N1 < 65,535 2 < 2 < N2 < 65,535 N1 * N2 > 50 Using the equations above, the minimum and maximum data sampling rates for the intern
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When configured for a 48-bit divider, the first sampling period will be slightly longer than the others because the first clock period is required to load the initial value of the multi-function timer. The following equation calculates the additional time of the first period: t = 100ns * [N1 * N2] add To minimize the amount of additional time required for the first sample, select clock dividers such that N1 and N2 are as small as possible and N3 is as large as possible. Using the
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When the multi-function timer is used as a pre-divider, the frequency of the external clock input may be varied from DC to 10 MHz as long as the high portion of the clock is at least 30ns and the low portion is at least 50ns. Except for the first period, the sampling rate of the DAQ-12 will be the external clock frequency divided by the count value written to the multi-function timer. Since one clock pulse is required to load the initial count value into the timer, the first sampling interval
