Campbell Scientific CR9000X Measurement and Control System - Manual (Page 252)

Section 7. Measurement Instructions
7-28
Remarks
This Instruction allows the use of the SDM-INT8, 8 Channel Interval Timer,
with the CR9000X. The SDM-INT8 is a Synchronous Device for the
Measurement of Intervals, counts between events, frequencies, periods, and/or
time since an event. See the SDM-INT8 manual for more information about its
capabilities.
This instruction must NOT be placed inside a conditional
statement or SubScan.
Parameter Enter SDMINT8 PARAMETERS
Dest
Variable or
Array
The array where the results of the instruction are stored. For all output options except
Capture All Events, the Dest argument should be a one dimensional array with as many
elements as there are programmed SDM-INT8 channels. If the "Capture All Events"
OutputOption is selected, then the Dest array must be two dimensional. The magnitude of
first dimension should be set to the number of functions (up to 8), and the magnitude of the
second dimension should be set to at least the number of events to be captured. The values
will be loaded into the array in the sequence of all of the time ordered events captured from
the lowest programmed channel to the time ordered events of the highest programmed
channel.
Address
Constant
The INT8 is addressable using internal jumpers. The jumpers are set at the factory for address
00. See Appendix A of the INT8 manual for details on changing the INT8 address.
Config8_5
Config4_1
Constants
Each of the 8 input channels can be configured for either high or low level voltage inputs, and
for rising or falling edges. Config8_5 is a four digit code to configure the INT8's channels 5
through 8. Config4_1 is a four digit code to configure the INT8's channels 1 through 4. The
digits represent the channels in descending order left to right. For example, the code entered
for Config8_5 to program channels 8 and 6 to capture the rising edge of a high level voltage,
and channels 5 and 7 to capture the falling edge of a low level voltage would be "0303". See
section 2 of the INT8 manual for requirements of high and low level voltage signals.
Digit Edge
0 High level, rising edge
1 High level, falling edge
2 Low level, rising edge
3 Low level falling edge
Funct8_5
Funct4_1
Constants
Each of the 8 input channels can be independently programmed for one of eight different
timing functions. Funct8_5 is a four digit code to program the timing functions of INT8
channels 5 through 8. Funct4_1 is a four digit code to program the timing functions of SDM-
INT8 channels 1 through 4. See section 5.3 of the INT8 manual for further details.
Digit Results
0 None
1 Period (msec) between edges on this channel
2 Frequency (kHz) of edges on the channel
3 Time between an edge on the previous channel and the edge on this channel
(msec)
4 time between an edge on channel 1 and the edge on this channel (msec)
5 Number of edges on channel 2 between the last edge on channel 1 and the edge
on this channel using linear interpolation
6 Low resolution frequency (kHz) of edges on this channel
7 Total number of edges on this channel since last interrogation
8 Integer number of edges on channel 2 between the last edge on channel 1 and the
edge on this channel.
NOTE