Operator`s manual

SECTION 9. INPUT/OUTPUT INSTRUCTIONS
9-11
location number of Instruction 23 in the program
table. I
2
divided by I
3
is the multiplier and I4 the
offset (to the raw data) determined by the first
calibration. I
2
is a fixed value determined by the
input range selected. I
5
through I
n-2
are the raw
measurement data. Thus, the value of the first
measurement sent (M
1
) in millivolts is:
M
1
= I
2
/I
3
(I
5
- I
4
)
The measurement data are sent in the order that
the measurements are made (i.e., the first
measurement for each channel, then the second
measurement for each channel, etc.). The last 2
integers sent, I
n-1
and I
n
correspond to I
3
and I
4
and are the results of the final calibration.
NOTE: When the raw serial data
option is selected, the
CALIBRATION VALUES are for
CONVERSION TO MILLIVOLTS
ONLY. Parameters 11 and 12 are
ignored.
SCAN INTERVAL
Instruction 23 has its own scan interval
independent of the execution interval of the
program table in which it resides. The resolution
of the clock timing the execution interval is 813
nanoseconds. This scan interval, entered in
Parameter 5 (in milliseconds), is the time
between each scan of the specified channels
(i.e., if 4 channels are specified in Parameter 1,
and the scan interval is 5ms, then the 4
measurements will be repeated every 5ms).
The minimum time that is allowed per
measurement is 0.97ms. The maximum time
that is allowed per measurement is 50ms. If the
scan interval entered does not allow this much
time per measurement (e.g., if with 4 reps, an
interval less than 3.88ms is entered), an error
code, E 61, will be displayed when the program
is compiled. When sending data to the serial
port, the rate at which the data can be
transferred may limit the scan interval (e.g., at
9600 baud the minimum time per measurement
is 2.2ms).
NOTE: Instruction 23 can be
aborted by keying #.
Burst/Telecommunications Considerations
The 21X will not respond to attempts to enter
telecommunications while Burst measurements
are in progress.
If the Burst Measurement instruction is
encountered while telecommunications is in
progress, the destination of the data determines
whether or not the instruction is executed:
Burst data sent to input locations- If the
Burst instruction specifies that Burst data be
sent to input locations, all telecommunication
activity will be suspended. After the Burst
trigger condition is met and all Burst
measurements made, Telecommunications can
resume.
Burst data sent to Serial I/O Port- If the Burst
instruction specifies that Burst data be sent to
the serial port (i.e., Storage module), 21X
program execution will pause until
telecommunications is exited. During this pause
telecommunications (i.e., view input locations,
Monitor Mode with Term, etc.) can continue. No
Burst measurements are made while in
telecommunications and no Burst data is sent to
the serial port. After telecommunication has
ended, datalogger program execution will
resume as if the Burst instruction were just
executed.
PARAM. DATA
NUMBER TYPE DESCRIPTION
01: 2 Repetitions (no. of
channels)
02: 2 Range code (12-15)
03: 2 1st channel for analog
measurements
04: 4 Option, 4 digit code
ABCD
A Trigger
0 - Trigger on 1st
analog channel
1 - Digital trigger on
single-ended
Channel 1 (1H)
2 - Same as 0, but set
Digital Control Port
#1 high when
trigger is met, Low