40 PCL-818L User's Manual
You can specify channel settings by writing directly to the MUX scan
register. You use the MUX scan register to point to a specified channel
when you set channel input ranges (with BASE+1). After you set the
input range, you will need to reset the MUX register for the proper
start and stop channels.
Trigger mode
You can trigger an A/D conversion from software, the card's on-board
pacer or an external pulse. Bits 1 and 0 of register BASE+9 select the
trigger source.
1. If you select software triggering, a write to the register BASE+0
with any value will trigger an A/D conversion. You would not
normally use software triggering in high speed A/D applications
because the triggering rate is too slow.
2. You can use the PCL-818L's on-board Intel 8254 programmable
interval timer/counter to generate timing related signals. Counters
1 and 2 of the Intel 8254 can provide A/D converter trigger pulses
with precise periods. The 8254 can generate pacer output between
2.5 MHz and 71 minutes per pulse. Chapter 8 covers the details of
the Intel 8254 timer/counter.
Pacer triggering is ideal for interrupt and DMA data transfer,
normally used in A/D applications which require higher conver-
sion speeds.
3. You can provide an external signal to trigger the A/D conversion.
Connect the external signal to TRIG0 (pin 35 on connector CN3).
You would normally use external triggering if your application
requires A/D conversions not periodically, but conditionally, e. g.,
measuring a voltage when a limit switch closes. The A/D conver-
sion starts at the rising edge of the external trigger pulse.
Summary of Contents for PCL-818L
Page 1: ...PCL 818L High performance DAS card with programmable gain ...
Page 5: ...Chapter 1 General information 1 1 General information C H A P T E R ...
Page 13: ...Chapter 2 Installation 9 C H A P T E R 2 Installation ...
Page 25: ...Chapter 3 Signal connections 21 3 Signal connections C H A P T E R ...
Page 31: ...Chapter 4 Register structure and format 27 4 Register structure and format C H A P T E R ...
Page 41: ...Chapter 5 A D conversion 37 C H A P T E R 5 A D conversion ...
Page 47: ...Chapter 6 D A conversion 43 6 D A conversion C H A P T E R ...
Page 50: ...46 PCL 818L User s Manual ...
Page 51: ...Chapter 7 Digital input and output 47 7 Digital input and output C H A P T E R ...
Page 53: ...Chapter 8 Programmable counter timer 49 8 Programmable timer counter C H A P T E R ...
Page 61: ...Chapter 9 Direct memory access operation 57 9 Direct memory access operation C H A P T E R ...
Page 64: ...60 PCL 818L User s Manual ...
Page 65: ......
Page 68: ...Appendix C PC I O port address map 65 C PC I O port address map A P P E N D I X ...
Page 70: ...Appendix D Calibration 67 D Calibration A P P E N D I X ...
Page 73: ...70 PCL 818L User s Manual ...
Page 75: ...2 PCL 818L User s Manual ...