User manual

The following examples demonstrate the use of reading count, timed scans, delay, and
external scanning.
One of the configuration options for stepping and scanning is the reading count. The ex-
ample of Figure 3-14 shows how different settings of RDG CNT affect these operations:
• With a reading count (0010) equal to the scan list length (10), a step operation con-
secutively closes ten channels and sends an output trigger after each channel. A
scan operation also consecutively closes ten channels but sends an output trigger
only at the end of the scan.
• With a reading count (0020) greater than the scan list length (10), stepping yields 20
channel closures and 20 output triggers. Scanning also goes through the scan list
twice but sends an output trigger only at the end of each scan.
• With a reading count (0002) less than the scan list length (10), stepping yields two
channel closures and output triggers. Scanning goes through the entire scan list and
sends an output trigger but only two readings are stored.
NOTE If the reading count divided by the scan list length is not an integer, it is rounded
up. For example, if the reading count is 15 and the scan list length is 10, there will
be two output triggers for scanning.
The differences between stepping and scanning counters for bus commands are summa-
rized in Table 3-3.
TYPE: INT
MIN CHAN: 1
MAX CHAN: 10
TIMER? OFF
RDG CNT:
0010 0002
0020
STEP
20 channel closures
20 output triggers
SCAN
10 channel closures (x2)
2 output triggers
RECALL
20 Readings
STEP
10 channel closures
10 output triggers
SCAN
10 channel closures
1 output triggers
RECALL
10 Readings
STEP
2 channel closures
2 output triggers
SCAN
10 channel closures
1 output triggers
RECALL
2 Readings
Note: "Factory setup" on the
Model 2000 is assumed.
SHIFT-CONFIG
Figure 3-14
Internal scan-
ning example
with reading
count option
2000-900 (J - Aug 2010) BOOK.fm Page 27 Wednesday, October 12, 2011 12:29 PM