Malvern Instruments Spraytec, User Manual

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Data collection – trigger advance or delay
Use the Data collection settings in the above dialogue to determine when data
collection starts, relative to the trigger. A trigger advance or delay can be applied to
all trigger options. In the above example data collection starts 2ms before the
trigger. The options are:
.
Advance – measurement begins a set time before the trigger. This is possi-
ble because data is collected in advance and buffered.
.
Delay – measurement begins a set time after the trigger.
External triggers
With an external trigger, measurement begins on receipt of an electrical signal
from an external device. The external device must be connected to the TRIGGER
INPUT port on the back of the Receiver module.
The Spraytec can respond to two types of trigger signal:
.
Closed Switch Trigger – here a simple switch trigger is used to start the
Spraytec measurement. If this is required set the slope and impedance set-
tings to the defaults for the external trigger.
.
TTL Trigger – this is an industry standard trigger configuration, trigger-
ing a system by an electronic input moving between two states: a "low" state
where the applied voltage is 0 volts and a "high" state where the applied
voltage is 5 volts. The trigger can activate the Spraytec measurement, either
based on a move from low to high voltage (a positive slope trigger) or a
move from high to low voltage (a negative slope trigger).
The Spraytec can be used with low impedance (<50 Ohm) sources or high
impedance (up to 1kOhm) sources. Select the correct slope and impedance
settings for the trigger during SOP creation.
Grouping
To display the Grouping option, click the Advanced button on the Rapid
Measurement dialogue shown above. Grouping allows users to specify different
data groups within a given event. The start and end time for each data group is
defined by the receipt of an external trigger. This trigger must be defined in the
same way as an external trigger which is used to indicate the start of a
measurement event.
The available options for grouping are:
.
No grouping – in this case the Spraytec will not record any external trig-
ger activity during an event.
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