Campbell Scientific SDM-SW8A 8-Channel Switch Closure Input Module - Manual (Page 13)

SDM-SW8A Switch Closure Input Module
6.2 Edlog Programming
Instruction 102, Table 6, is used to address and retrieve information from the
SW8A.
TABLE 6. Instruction 102 - SDM-SW8A
Parameter
Number Data
Type
Description
01: 2 Repetitions
02: 2 Module Address (00..33)
03: 2 Function Option (0=State, 1=Duty 2=Counts,
3=Signature)
04: 2 SDM-SW8A Starting Channel (1..8)
05: 4 Starting input location for results
06: FP Mult
07: FP Offset
Instruction 102 is not contained in all CR10 or 21X PROMS. To
verify that the datalogger contains the Instruction, enter 102 into
a datalogger Programming Table. If the Instruction is accepted,
the PROM contains the Instruction. NOTE
Repetitions (Reps, Parameter 1) specifies the number of SW8A channels to
read. Parameter 2 is the address of the first SW8A. If more Reps are
requested than exist in one module, the datalogger automatically increments
the address and continues to the next SW8A. The address settings for the
SW8As must be sequential. For example, assume two SW8As with addresses
of 22 and 23 are connected, and 12 Reps are requested. Eight channels from
the first SW8A and the first four channels from the next will be read.
Only one Function Option (Parameter 3) may be specified per Instruction. If
all four functions are desired, four Instructions must be entered in the
datalogger program.
Function Option 0 provides the state of the signal at the time 102 is executed.
A 1 or 0 corresponds to high or low states, respectively.
Function Option 1 provides signal duty cycle. The result is the percentage of
time the signal is high during the sample interval.
Function Option 2 provides a count of the number of positive transitions of
the signal.
Function Option 3 provides the signature of the SW8A PROM. A positive
number (signature) indicates the PROM and RAM are good, a zero (0)
indicates bad PROM, and a negative number indicates bad RAM. Function
Option 3 is not used but is helpful in "debugging." Only one Rep is required
for Option 3.
9