Acqutek - PA-ST12(-H) (details)
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Similar / Related Products PI-IO48A - PA-CP12 - PA-ST12(-H) - PA-MA12(-H) - PA-MD12(16) - PA-AD12(-H) - PA-DA12(16)
XC-IO96 - XC-AD12 - XC-DA12
XI-PI08 - XI-IM04 - XO-RR08 - XO-SRD4/XO-SRA4 - ST-XD02 - ST-DM37 - IC-XCXD

PA-ST12(-H) Brief Description
Multi-I/O Card (A/D D/A & Digital I/O)

Description - Model No - Expansion - Block Diagram - A/D - D/A - I/O - Register - Programming - Specifications


    12 bit, 20 us or 10 us analog to digital (A/D) convertor.
    32 single-ended or 16 differential analog inputs.
    8254 timer provides background conversion.
    12 bit, 10 us digital to analog (D/A) convertor.
    2 voltage analog output.
    16 digital inputs.
    16 digital outputs.


    The PA-ST12 and PA-ST12-H are 16 differential/32 single-ended input channels of 12 bit 20us (PA-ST12) or 10us (PA-ST12-H) A/D and 2 voltage out, 12 bit 10us D/A cards with an 8254 Timer/Counter on board which generates an accuracy signal for A/D background conversion.

    This module also comes with programmable gain control that allows the user to program the gain by software. 32 lines of digital I/O are also available, as well as, various expansion models like S.S.R. O/P, reed relay O/P, photo-coupled I/P and screw terminal boards.


    Function PA-ST12PA-ST12-H
    A/D Resolution 12 Bit12 Bit
    Channels 16 Differential or 32 Single-ended16 Differential or 32 Single-ended
    Conversion time20 us10 us
    Accuracy 11 Bit11 Bit
    D/A Resolution12 Bit12 Bit
    Channels 22
    Conversion time10 us10 us
    Accuracy 11 Bit11 Bit
    Digital I/ODigital I/P16 Bit16 Bit
    Digital O/P 16 Bit16 Bit


    Both inputs and outputs, have optional expansion modules (daughter cards) that extend the I/O for interfacing operations. These modules are called XDI expansion boards and include options like reed-relays or photo-coupled input modules. The PA-ST12(-H) could support two input cards and two output cards totaling 32 individual lines in all (half input/half output).

    Model No. Function
    XI-PI08 3-32V photo-coupled input expansion
    XI-IM04-32 12-32V AC/DC input expansion
    XI-IM04-140 90-140V AC/DC input expansion
    XI-IM04-280 180-280V AC/DC input expansion
    XO-RR08 10VA reed relay output expansion
    XO-SRD4 3A 5-60V DC S.S.R. output expansion
    XO-SRA4 3A 24-280V AC S.S.R. output expansion
    ST-XD02 2 XDI screw terminal board
    ST-DM37 Screw terminal board for A/D D/A connector
    IC-XCXD Chassis for XCI/XDI expansion cards



    Analog Input

    The PA-ST12(-H) provides 32 single-ended or 16 differential channels of 12 bit, 20/10us analog to digital conversion.

    ADC block diagram -

    The signal connector - The analog input signal connector is a 37 pin D-type male connector.

    A/D channel selection -The PA-ST12(-H) can be configured for 16 differential inputs or 32 single ended inputs. The configuration is set by an on-board jumper. The channel can be selected by writing to the base+2 port.

    Sample and hold - The input signal will be held during the conversion.

    A/D conversion control - The A/D conversion can be triggered in three ways. They are selected by programming the command port base+3.

      Trigger method 1 : S/W trigger conversion
      This conversion method is very easy to implement because the software is directly controlling the A/D conversions. The conversion is started by writting any data to the S/W trigger port (base+0).
      Trigger method 2 : External clock conversion
      The external clock conversion consists of using an external clock or pulse (coming in from a jumper) to trigger the A/D conversion. This gives the user great flexibility in synchronizing the A/D with other devices.
      Trigger method 3 : 8254 timer conversion
      The 8254 timer conversion method uses the 8254 timer controller to generate accurate time pulses to trigger the start of conversions. An option that goes with this, is to gate the 8254 timer trigger signals with the external signal. This would give the user external control over A/D conversions using the 8254 timer.

    A/D conversion - When an A/D conversion takes place, the EOC (End Of Conversion) line goes high. Once the start conversion signal is received, conversion of the voltage at the selected channel is initiated. Once the conversion is initiated, no other start conversion command will be accepted until the completion of the conversion. Upon completion of the conversion, the EOC line goes low (in timer or external clock trig mode, an interrupt will occur). Next, the least significant byte (LSB) and the most significant byte (MSB) of the digital value for the voltage can be read from the data registers, base+0 and base+1 respectively. There are two methods to read the conversion result :

    Reading conversion result - There are two methods to read the conversion result :

      Method 1 : Polling the EOC status
      This method is the simplest method to do A/D conversions and read the data. However, this method ties up the CPU because one must keep polling the EOC bit in the status register so that one can know when A/D conversion is completed.
      Method 2 : Interrupt
      This method is more efficient than polling the EOC status, because upon completed conversion, the PA-ST12 interrupts the CPU to read the conversion results. In other words, the conversion is done in the background, leaving the CPU to do more important tasks.

    Conversion status -

    Reading status

    The base+3 port contains the critical information for the setup and condition of the A/D while the base+2 port contains information on the selected channel and selected gain range.

    Analog Output (D/A)

    The PA-ST12 provides two voltage output channels of 12 bit 10us digital to analog conversion.

    DAC block diagram -

    Data register - The PA-ST12(-H) uses 4 I/O ports to control D/A conversions. The ports are base+4 through base+7. Using 2 ports enables the user to send a 12-bit word to the D/A converter using an 8-bit bus without getting glitches on the output. Here is an example of the data register scheme. Say a user wishes to convert the digital value from 1AFH to 1B0H to an analog value. Using the standard approach of sending 8 bits at a time would result in a glitch on the output at the digital values 1AFH-1A0H-1BFH (sending LSB first, then MSB) or 1AFH-1BFH-1B0H (sending MSB first, then LSB). However, using the PA-ST12(-H) one would write the 0H (4 least significant bits) to the temporary register (base+4 for channel one and base+6 channel 2). Next, the user would write 1BH (8 most significant bits) to the output port (base+5 for channel 1 and base+7 for channel 2). Upon writing the MSB to base+5, the data in the temporary register is automatically be sent to the output, thus, both MSB and LSB arrive at the D/A simultaneously. (i.e. no glitch)

    D/A conversion - D/A conversion is accomplished using a 12 bit D/A conversion chip. The 12-bit words are sent from the data bus and a temporary register simultaneously. This enables a 12-bit word to be sent from an 8-bit data bus without getting odd glitches on the output.

    The signal connector - The signal connector for the D/A output signals is the same 37 pin male D-type connector used for the A/D. The A/D and the D/A share the same connector.

    Optional product

    Model No.Function
    ST-DM37 Screw terminal board for A/D D/A
    IC-XCXD Chassis for ST-DM37 and XCI/XDI cards

    Digital I/O

    The PA-ST12(-H) provides 32 channels digital I/O; 16-bit digital outputs and 16-bit digital inputs.

    Digital output - Digital output consists of two 8-bit dedicated output paths. To write data out of these two paths a user simply writes to the I/O ports; base+8 is the output port for CON1, base+9 is the output port for CON3.

    Digital input - Digital input consists of two 8-bit dedicated input paths. To read data from these two paths a user simply reads from the I/O ports; base+8 is the input port for CON2, base+9 is the intput port for CON4.

    The digital I/O connectors - There are four connectors for the digital I/O. Each consists of a 20 pin dual-in-line box header. Connectors 1 and 3 (CON1 & CON3) are output and connectors 2 and 4 (CON2 & CON4) are input.


    Port Default Direction Function
    +0 02E0H I/O read A/D LSB data
    I/O write Start A/D conversion
    +1 02E1H I/O read A/D MSB data
    I/O write None
    +2 02E2H I/O read A/D channel select
    I/O write
    +3 02E3H I/O read A/D status
    I/O write A/D command
    +4 02E4H I/O write D/A 1 LSB data
    +5 02E5H I/O write D/A 2 MSB data
    +6 02E6H I/O write D/A 1 LSB data
    +7 02E7H I/O write D/A 2 MSB data
    +8 02E8H I/O read Digital I/P 1
    I/O write Digital O/P 1
    +9 02E9H I/O read Digital I/P 2
    I/O write Digital O/P 2
    +12 02ECHI/O read8254 counter 0 data
    I/O write
    +13 02EDHI/O read8254 counter 1 data (A/D timer conversion)
    I/O write
    +14 02EEHI/O read8254 counter 2 data (A/D timer conversion)
    I/O write
    +15 02EFHI/O read8254 read-back status
    I/O write8254 command


    Shipped with this board are Utility, Library and Sample Programs. These programs are included at no additional expense with this product.

    Utility Program - This program will provide comprehensive testing of various functions of the board to ensure proper operation.
    Library And Sample Programs - The library program provides the interface to Turbo-C, Microsoft Quick Basic, Microsoft Quick C, Microsoft GW-BASIC, IBM BASIC and Assembler.
    Labtech Notebook Driver - A Labtech's Notebook driver interface is available as an optional product.
    Window Driver - Window 3.1 and Window NT driver interface is available as an optional product.


    Analog Input (A/D)
    Resolution 12 Bits
    Input channel 32 Channels (single-ended)
    16 Channels (differential)
    Input voltage range -5V to +5V, -10V to +10V
    0V to +5V, 0V to +10V
    Accuracy 1 Bits
    Conversion time 20 us (PA-ST12)
    10 us (PA-ST12-H)
    Overvoltage 35V
    Gain controller 1, 2, 5, 10, 20, 50 or user define by
    H/W jumper setting or S/W programming
    Conversion method S/W trig External clock trig
    Internal 8254 timer trig
    Internal 8254 timer trig (perced)
    Connector 37 pins D-type male connector
    (shared with D/A)
    Analog Output (D/A)
    Resolution 12 bits
    Channel l 2
    Output voltage range-5V to +5V, -10V to +10V
    0V to +5V, 0V to +10V
    Accuracy 1 bit
    Conversion time 10 us
    Connector 37 pins D-type male connector
    (shared with A/D)
    Digital I/O (DIO)
    Number of digital input 16 bits
    Input type 74LS244
    Input high/low voltage 2.0V/0.8V
    Number of digital output16 bits
    Output type 74LS273
    Output high/low voltage 2.4V/0.5V
    Digital I/O connector 4 XDI connectors 20 pin
    dual-in-line male box header
    Counter Timer (CLK)
    Controller 8254
    Counters 3 16-Bit down counter
    2 for A/D timer conversion
    1 for user's application
    Clock source 4 MHz
    Input/output type TTL
    Interface Characters
    Compatible bus IBM PC and compatibles
    Data path 8 Bits
    Interface type 12 Bit I/O mapped
    I/O location occupied 16
    Port address range 100H to FF0H
    Interrupt IRQ2,3,4,5,7,10,11,12,14,15
    Interrupt source A/D end of conversion (EOC)
    Power consumption 1.25A / +5V
    Operating temperature +5 ° C to +5 ° C
    Storage temperature -25 ° C to +85 ° C
    Operating humidity 0 to 90% non-condensing
    storage humidity 0 to 90% non-condensing
    Weight 280 g
    Dimension 33.6 x 12.6 x 2.0 cm

Copyright © 1996 - 2000 by Acqutek Corporation, Inc.