WIKA CTD4000, Operating Instructions Manual

Page: 24 / 68

22 WIKA operating instructions, model CTD4000
14366831.01 05/2020 EN/DE
EN
8. Serial communication
8. Serial communication
On the front of the calibrator there is a 9-pole socket
connected to the temperature controller, which enables the
calibrator to be completely controlled by a PC (see figure) by
the RS-232 input.
Pin assignment, front view
The external PC must comply with the IEC 950
standard.
▶
After switching the calibrator on and connecting the serial
interface, wait until the system has booted up.
▶
To activate the serial communication, press the [E] button
on the display.
General characteristics
Baud rate 9600
N. Bit 8
Parity No
Stop bit 1
The communication operates in half-duplex format which
means that transmission and reception cannot happen
simultaneously.
The controller replies only after receiving a command; it
never replies by itself.
The command and reply are ASCII character strings, as
detailed below. The communication program will be able
to convert ASCII to decimal to extract numeric values. The
default address is 1.
8.1 List of the variables and parameters
Variable Designation Parameters
Adjustable Readable
0 Set point x ... 9999

1 Ramp 1 = On
0 = Off
1 = On
0 = Off
2 Set point 2 x ... 9999

3 Gradient x ... 9999

5 Proportional band 0 ... 100 %

6 Integral time in seconds xxx

5 4 3 2 1
6 7 8 9
Tx
Rx
Variable Designation Parameters
Adjustable Readable
7 Derivative time in
seconds
xxx

10 Units 0 = °C
1 = °F
0 = °C
1 = °F
13 Cod1 (access key)
2 = preset
 
14 Baud rate
9600 (preset)
- 2400
4800
9600
19200
15 Address
 
16 Serial number
 
19 Min. set point -

20 Cod2
3 = preset
- 3
21 Delay ON
OFF

22 Switch-on temperature -

23 Switch-off temperature -

24 Firmware version -

27 Internal sensor type - 0 = Pt100
2 = type K
28 Stability range -

29 Stability symbol - 0 = no
1 = yes
31 Alarm setting -

33 Offset of ambient
temperature
-

Each commands string is ASCII character succession.
First is $ character; the next must indicate the instrument
address (default 1) and then is the command (4 characters).
Possibility
RVAR = Data reading
WVAR = Data writing
The final part of string depends on the type of command. The
character <cr> concludes the sequence.