Trigger auto re-arm on positive or negative edges

The analogue trigger input is continuously sampled at the selected sample rate. If the user programmed re-arm level is crossed by the trigger signal from lower to higher values (rising edge)then the trigger engine is armed. When the separately set trigger level is now crossed the card will start to record. During recording further triggers are ignored until the record period has completed then the trigger engine will accept a new re-arm ready for the next trigger.
Auto re-arm also works for higher to lower value (falling edge) situations, where required. Choice of slope is simply made by the programmer in the appropriate register.
N.B. The re-arm option is very useful in situations where noisy signal could result in false triggers, i.e the trigger recording is only desired following a major amplitude change of known direction.