Series 3700A Switch and Control Cards Reference Manual
Section 13: Model 3750 multifunction control card
3700AS-909-01 Rev. A / Preliminary
13-9
•
To read the current total closure counts:
channel.setmode("1009", channel.MODE_RISING_TTL_EDGE)
count = channel.read("1009")
•
To reset the counter to zero using an explicit command:
channel.write("1009", 0)
•
To preset the counter to a value (for example, 100) using an explicit command:
channel.write("1009", 100)
•
To automatically reset the counter back to zero for a read command:
channel.setmode("1009", channel.MODE_RISING_TTL_EDGE_READ_RESET)
Using the gating function
The gate input determines whether the totalizer ignores or counts when the appropriate totalizer
threshold is crossed. Gating is enabled by default; that is, the two inputs that control gating are biased
to the appropriate level so that no connections have to be made for the totalizer to count. Gating of
the count is accomplished in one of two ways:
•
Driving the GATE + input below a TTL threshold (inhibit counting).
•
Driving the GATE - input above a TTL threshold (inhibit counting).
The following diagram illustrates how gating works using the GATE + input with a totalizer configured
for TTL threshold and a rising edge trigger.
Figure: Model 3750 Gate Setup Time Example
Figure 70: Model 3750 Gate Setup Time Example
NOTE
The minimum gate input setup time must be satisfied for the event to be counted.