SENDING COMMANDS TO THE IMR
When sending commands to the unit a command string must be constructed.
The command string may consist of command codes, value identifiers, and
numerical data. Below is a table outlining the codes the indicator will recognize.
COMMAND
FUNCTIONS
T
transmits the requested information specified by the identifier
(A-I, K, & L)
V
change a value specified by the identifier (C-F, K, & L)
N
address a particular indicator in a multiple unit loop (0-99)
R
reset a value specified by the identifier (B-D, G, H, I, & J)
P
print per programmable print options (A-I)
VALUE
IDENTIFIERS
SERIAL MNEMONICS
A
temperature
RTD
B
integrator/totalizer
TOT
C
alarm #1
AL1
D
alarm #2
AL2
E
hysteresis #1
HS1
F
hysteresis #2
HS2
G
peak reading
PEK
H
valley reading
VAL
I
zero offset
OFS
J
offset input
—
K
analog low
ANL
L
analog high
ANH
Note: RJ - offset the input (re-zeros). When the input is offset (via front panel or
“RJ”) the amount is stored in the offset reading (I). Ex. When an offset is
performed, the display reads “5.0”, the offset value will be “-00005.0” (and
the display will show 0.0).
A command string is constructed by using the above commands and
identifiers along with any data values that are required. The indicator will accept
“+”
or
“-”
in front of the data value. Numbers without
“+”
are understood to be
positive. Leading zeros can be eliminated and both lower and upper case
characters are accepted. The address command is used to allow a command to be
directed to a specific unit on the loop. If the indicator is assigned an address of
“0
”, transmission of the address command is not required. This is done where
only one indicator is in the loop.
The command string is constructed in a specific logical sequence. The
indicator will reject command strings that do not conform. Only one operation
can be performed per command string. Below is a description of how to construct
a command string.
1. If the indicator has an address other than zero, the first two characters of the
string must consist of the address command
(N)
followed by the unit
address number
(0-99)
. If the indicator has an address of 0, the address
command is optional.
2. The next two characters in the string are the actual command the indicator
must perform and the identifier on which it operates. Command P-print,
Value I-zero offset and J-offset input, have implied operators and need no
additional characters.
3. If the change value command is being used
(V)
, the next characters in the
string after the value identifier, are the numerical data. When sending
numerical data, such as change an alarm value, the correct number of digits
to the right, must be included. As an example, to change an alarm value
from 750.2 to 500.0. Sending 500 would cause the indicator to see 50.0 and
change the alarm value accordingly.
4. All commands must be terminated by an asterisk
(*)
. The indicator will not
respond to any other code. Carriage return and line feed are not valid
terminators and should be suppressed with the character
“;”
, if using a
BASIC print statement
(ex. Print “N9TA*”;)
.
COMMAND STRING EXAMPLES
Indicator with address 3, transmit temperature reading.
N3TA*
Indicator with address 0, change alarm #1 to 1500.
VC1500*
Indicator with address 1, reset totalizer.
N1RB*
Indicator with address 99, print the print options.
N99P*
Indicator with address 0, zero the offset value.
RI*
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