Datasheet

Function Chronos
The function Chronos is a timer interface which allows to measure the time
between two “events” like a chronometer.
3 functions are available:
a 32-bit timer to create a time reference,•
a 32-bit measuring timer to determinate and measure the time •
between start and stop pulse.
3 digital inputs and 3 digital outputs•
Properties
Optical isolation of the inputs and outputs through opto-couplers to •
prevent ground loops
Interrupt status at the end of the measuring time
•
Timer readable•
Input and output channels can be inverted through software, •
Software GATE possible
Function description
The pulse signals from Timer 0 are counted between the start pulse signal
and the stop pulse signal. The number of pulses is then stored in the
measuring timer and can be read through I/O read commands. The timer 0
is used as a time reference generator. The divider factor is written in timer 0
32-bit counter
32-bit reload register
Divider factor
PCI clock
(30 MHz or 33 MHz)
Time base
32-bit clear counter
Time measurement
Divider factor
Time measurement
or internal reference
of the board (10 MHz)
Timer 0
/ 4
Clock 0
OUT 0
Latch register
Clock 1
Clock
Stop
Gate 1
Start
Modes
= 1
= 1
SC
Start
Stop
Inc Cx
Inc Dx
Cx
Dx
and determines the output frequency.
The input frequency is set according to the PCI clock pulse or to the 10 MHz
onboard clock generator. Timer 0 is synchronised with the start event or
with the 40 MHz quartz of the board.
Timer 0 can be read at any time. The Chronos function can be used in 8
different modes.
Used signals
Pin name Signal type Function
Ax +/- Diff./TTL, 24 V* Digital output 1; set to “0” after reset
Bx +/- Diff./TTL, 24 V* Digital output 2; set to “0” after reset
Cx +/- Diff/TTL/24 V* Start pulse for measuring
Dx +/- Diff/TTL/24 V* Stop pulse for measuring
Ex 24 V / 5 V optional Digital input 0, inverting
Fx 24 V / 5 V optional Digital input 1, inverting
Gx 24 V / 5 V optional Digital input 2, inverting
Hx 24 V / 5 V optional Digital output 0; set to “0” after reset
Block diagram Chronos
x: Number of the function module (See pin assignment page 179)
*24 V for the APCI-1710-24V
181
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PCI, counter – APCI-1710