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WIKA operating instructions, model CTD4000
14366831.01 05/2020 EN/DE
EN
8. Serial communication
8.2 Data reading
For reading, use the command
RVAR
.
Example:
Read the current set point (variable 0):
The command string is
$1RVAR0_<cr>
Meaning of the command character string
$
= Start of message
1
= Instrument address
RVAR
= Read command
0
= Number of the variable to read (see table)
_
= Space
<cr>
= End of message
Response (example for 110.0 °C/°F)
The response string is:
*1_110.0
The character
<cr>
concludes the message.
Meaning of the response character string
*
= Start of the response
1
= Instrument address
_
= Space
110.0
= Numerical value of data with the character [.]
in order to separate the decimal part of the
number
<cr>
= End of message
The response does not include the measure unit. To read the
unit read the variable 10:
The command string is
$1RVAR10_<cr>
The response string is
*1_0
for °C
The response string is
*1_1
for °F
8.3 Data writing (FLOAT VARIABLES)
For reading, use the command
WVAR
.
Example:
Writing the set point to 132.4 °C (variable 0):
If the unit of the temperature is already
°C
, it is
sufficient to write the set point
The command string is:
$1WVAR0_132.4<cr>
Meaning of the command character string
$
= Start of message
1
= Instrument address
WVAR
= Writing command
0
= Number of the settable variable (see table)
_
= Space
132.4
= Numerical value of data with the character [.]
in order to separate the decimal part of the
number
<cr>
= End of message
At reception of the command, the answer of the instrument is:
*1<cr>
This string shows the recognition of the command.
If the unit of the temperature is not
°C
, the
variable 10 for "Units" must first be set to
"0"
.
The command string for this is:
$1WVAR10_0<cr>
Integers as variables
We have just shown the procedure for the writing of a float
data.
The variables 1 and 10 have two or more states (for example,
the unit) and to activate them it is necessary to assign these
variables the number corresponding to the one which should
be set, according to the table indicated below:
Variable
Designation
Parameters
1
Ramp
1
= ON
0
= OFF
10
Units
0
= °C
1
= °F
Example
The variable 1 corresponds to the activation of the ramp. If
you want to set it to
ON
in order to activate the ramp, you
should assign the value
0
, otherwise the value
1
.
The command string is:
$1WVAR1_1<cr>
Do likewise for the other variables.
