Advantech PCM-3780 manual Mode L Waveforms, Hardware-Triggered Delayed Pulse One-Shot

D.13 Mode L Waveforms

Hardware-Triggered Delayed Pulse One-Shot

Mode L is similar to Mode J except that counting will not begin before 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. The counter will start counting source edges and counting will proceed until the second TC.

Note that after application of a triggering gate edge, the gate input will be disregarded for the remainder of the count cycle. This differs from Mode K, where the gate can be modulated throughout the count cycle to stop and start the counter. On the first TC after application of the triggering gate edge, the counter will be reloaded from the Hold register. On the sec- ond TC, the counter will be reloaded from the Load register and counting will stop until a new edge is issued to the counter. Note that unlike Mode K, new gate edges must be altered every second TC to continue counting.

SOURCE

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 L Waveforms

PCM-3780 User Manual 58