SENDING COMMANDS TO THE IMS
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
input or process value
INP
B
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
tare reading
TAR
J
tare input
---
K
analog low
ANL
L
analog high
ANH
Note: RJ - tares the input (rezeros). When the input is tared (via front panel or
“RJ”) the amount is stored in the tare reading (I). Ex. When a tare is
performed, the display reads “5.0”, the tare 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 value s that are required. The indicator will
accept
“+”
or
“-”
in front of the data value and 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.
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 input 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 tare value.
RI*
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