D.10 Mode I Waveforms

Hardware-Triggered Delayed Pulse Strobe

Mode I is identical to Mode G, except that counting will not begin until a gate edge is applied to an armed counter. The counter must be armed before application of the triggering gate edge. Gate edges applied to a dis- armed counter are disregarded. An armed counter will start counting on the first source edge after the triggering gate edge. Countering will then proceed in the same manner as in Mode G. After the second TC, the counter will disarm itself. An ARM command and gate edge must be issued in this order to restart counting.

Note that after application of a triggering gate edge, the gate input will be disregarded until the second TC. This differs from Mode H, where the gate can be modulated throughout the count cycle to stop and start the counter.

SOURCE

WR

ARM

COMMAND

GATE

COUNT

X

L

L-1

L-2

2

1

0

H

H-1

H-2

2

1

0

L

VALUE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

TC OUTPUT

TC TOGGLED

OUTPUT

Mode I Waveforms

55

AppendixD

Page 63
Image 63
Advantech PCM-3780 manual Mode I Waveforms, Hardware-Triggered Delayed Pulse Strobe