Omega DAQ-12 - Manuals

United Kingdom : One Omega Drive, River Bend Technology Drive ISO 9002 Certified Northbank, Irlam, ManchesterM44 5EX, England Tel: 44 (161) 777-6611FAX: 44 (161) 777-6622Toll Free in England: 0800-488-488E-mail: [email protected] It is the policy of OMEGA to comply with all worldwide safety and EMC/E...

Table of Contents 29 4.2 Programming the 8254 Counter/Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.1.9 8254 Control Word/Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 4.1.8 Multi-Function Timer Register . . . . . . . . . . . . . . . . ...

List of Figures and Tables 25 Table 4-1. DAQ-12 Address Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 2-3. D/A Converter Mode Selection Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Table 2-2. A/D Conversion Fo...

1. Introduction The DAQ-12 is a high speed data acquisition adapter for IBM AT and compatible machinesoffering eight differential analog input channels with 16-bit resolution, two analog outputchannels with 12-bit resolution and four digital input/output lines. Other features of theDAQ-12 include: A...

1.2 DAQ-12 Specifications DACK 5, 6, 7 DRQ 5, 6, 7 DMA Levels: IRQ 2, 3, 4. 5, 6, 7, 10, 11, 12, 14, 15 Interrupt Levels: 0000H - FFFFH I/O Address Range: ISA 16-bit Bus Interface: 491.4mA 374.9 mA +12 volts --- --- -12 volts 1204.9mA 1069.0 mA +5 volts --- --- -5 volts I(ms) I(t) Power Supply Power...

2. Circuit Board Description and Configuration The base address of the DAQ-12 is selected using switches SW1 and SW2. The operatingmode of the DAQ-12 is controlled by jumpers J1 through J7, while DMA and interruptselections are set with jumpers J8 through J11. Connections to external equipment are m...

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 theDAQ-12's gain control register. (* indicates unipolar mode not available with gain of ½ ). 83 2-3 4 +2.5/ ±1.25 82 2-...

n/a 0000 1111 1111 1111 10 0000 0111 1111 1111 0000 1000 0000 0000 5 0000 0100 0000 0000 0000 0100 0000 0000 2.5 0000 0000 0000 0000 0000 0000 0000 0000 0 1111 1100 0000 0000 n/a -2.5 1111 1000 0000 0000 n/a -5 Code Code Bipolar Unipolar Voltage Table 2-2. A/D Conversion Format Examples NOTE: The 'v...

The D/A converter channels may also be operated in unipolar mode: 0 to +5 volts, or bipolarmode: -5 to +5 volts. The output mode is selected using jumper J5 as shown in Figure 2-5. Inaddition, a gain selection jumper is provided to select an output gain of 1 or 2. When usingan external voltage refer...

2.3 Digital Input/Output The DAQ-12 offers four bits of digital output and four bits of digital input forcontrol/monitoring of external digital devices. The four digital output lines are LS TTLcompatible and will initialize low (0 volts) on power-up. The four digital inputs are also LSTTL compatible...

2.5 Clock Selection The DAQ-12 is equipped with a programmable clock circuit to produce data sampling ratesindependent from the clock rate of the host computer. An onboard 8254 programmableinterval timer, with a 10 MHz clock input and either two or three cascaded 16-bit timers,provides the sampling ...

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 clockdivider. The following criteria must be met when selecting val...

When configured for a 48-bit divider, the first sampling period will be slightly longer thanthe others because the first clock period is required to load the initial value of themulti-function timer. The following equation calculates the additional time of the first period: t = 100ns * [N1 * N2] add...

When the multi-function timer is used as a pre-divider, the frequency of the external clockinput may be varied from DC to 10 MHz as long as the high portion of the clock is at least30ns and the low portion is at least 50ns. Except for the first period, the sampling rate of theDAQ-12 will be the exte...

2.7 Direct Memory Access Direct Memory Access (DMA) transfers provide a way of transferring data from theDAQ-12's A/D converter into the personal computer's memory without using the CentralProcessing Unit (CPU). DMA capability enables other system software to be executed whiledata is being input fro...

2.8 Interrupts The DAQ-12 is capable of generating an interrupt from one of four sources: 1. End of conversion signal 2. DMA terminal count 3. Multi-function timer output 4. External interrupt input The interrupt source is software selected through the DAQ-12 control word register. Theinterrupt leve...

3. External Connections The DAQ-12 is equipped with a high density 62-pin connector as shown in Figure 3-1. 2 - CH1+ 4 - CH2- (CH10+) 6 - CH4+8 - CH5- (CH13+) 10 - CH7+ 12 - AOUT0 14 - DOUT0 6 - DOUT3 18 - EXT TRIG 20 - DIN1 22 - CH0+ 24 - CH1- (CH9+) 26 - CH3+ 28 - CH4- (CH12+) 30 - CH6+ 32 - CH7- ...

CHx-, CHx+ : Analog inputs to the analog to digital converter. When using differential inputmode, eight input channels are available (CH0+ to CH7+). When using single-ended inputs, 16 channels are available (CH0+ to CH15+). The first eight channels are inputthrough the connections marked CH0+ to CH7...

4. Register Description and Programming The DAQ-12 uses 16 consecutive I/O address locations in the range 0 to FFFFH. The cardutilizes these addresses for the registers listed in Table 4-1. (* indicates registers located in8254 counter). Read/Write 8-bit 8254 Control Word/Status Register Base F * Re...

4.1.4 D/A Converter 0 Register An output to this register causes the lower twelve bits of data to be converted to an analogoutput on D/A converter channel 0. The four most significant bits of data are ignored. Thisregister is 16-bit write only. 4.1.5 D/A Converter 1 Register An output to this regist...

4.2 Programming the 8254 Counter/Timer This section provides programming information for the 8254 counter/timer as implementedon the DAQ-12. For more details on the 8254, consult the Intel Micro-processor and PeripheralHandbook. To program any of the counters contained in the 8254 counter/timer, thr...