4 excite, delay, and measure – Campbell Scientific CR23X Micrologger User Manual
Page 139
SECTION 9. INPUT/OUTPUT INSTRUCTIONS
9-5
less than 4 seconds, control ports C5..C8
measure frequency much more precisely than
do pulse channels.
•
Pulse
Channels
Hz = counts / Execution Interval
Maximum Error (Hz) =
±
[1/(Execution
Interval - 50
µ
s)]
•
Control
Ports
Hz = counts / measured time (
±
0.5
µ
s)
since previous measurement
Error if Execution Interval < 4.0 s
Maximum Error (Hz) =
±
(0.5
µ
s)
∗
(Frequency)
2
Error if Execution Interval
≥
4.0 s
Maximum Error (Hz) =
±
[1/Execution Interval]
If there have been no new counts during the
scan interval (since last monitored), the
previous frequency is returned to the input
location. If it has been 4 seconds since a new
count has occurred, the 0 is returned to the
input location.
TABLE 9-2 Pulse Count Configuration
Codes
Code
Configuration
x0
High Frequency Pulse
(8 bit counter)
x1*
Low Level AC
x2
Switch Closure
x3*
High Frequency
(16 bit counter)
x4*
Low Level AC
(16 bit counter)
0y
No Change
1y
Long interval counts discarded
2y
Long interval counts discarded/
Frequency (Hz) output
xy*
10 Hz reset
xy--*†
100 Hz reset
* Options Applicable to Channels P1 to P4 Only
† 100 Hz reset only used with 8 bit counter
Example: 24-- Selects 16 bit, 100 Hz reset, Low Level
AC with a frequency output.
PARAM.
DATA
NUMBER
TYPE
DESCRIPTION
01:
2
Repetitions
02:
2
Pulse channel or
Control Port number for
first measurement
03:
2
Configuration code
(from above table)
04:
4
Input location for first
measurement
05:
FP
Multiplier
06:
FP
Offset
Input locations altered: 1 per repetition
TABLE 9-2A. Excitation Channel Options
0X Excite all reps with channel X
1X Increment channel with each rep
*** 4 EXCITE, DELAY, AND MEASURE ***
FUNCTION
This instruction is used to apply an excitation
voltage, delay a specified time, and then make
a single-ended voltage measurement. A 1
before the excitation channel number (1X)
causes the channel to be incremented with
each repetition.
Ranges 41-45 and 51-55 (Section 13.1) do not
have enough time between integrations to allow
a delay.
PARAM.
DATA
NUMBER
TYPE
DESCRIPTION
01:
2
Repetitions
02:
2
Range code (Table 9-1)
03:
2
Single-ended channel
number for first
measurement
04:
2
Excitation channel
number (Table 9-2A)
05:
4
Delay in hundredths of
a second
06:
4
Excitation voltage
(millivolts)
07:
4
Input location number
for first measurement
08:
FP
Multiplier
09:
FP
Offset
Input locations altered: 1 per repetition