Rs-232 Interface - Knauer K-120 Handbuch

14

RS-232 interface

Table 2
The serial interface at the rear of the instrument, item 2 in Fig. 3 on
page 8, allows direct pump control from a computer. If you are
going to integrate your pump in a HPLC system controlled by a
software package like EuroChrom® follow the instructions of the
software manual.
Also simple ASCII codes are able to control the pump. ESC
sequences are not needed. Thus, a simple terminal program may
be used. The specifications for data transfer are:
9600 baud
8 bit
1 stop-bit
no parity check
The following functions can be controlled by the PC. After
successful command transfer, the receipt OK will be sent back
from the pump. Inadmissible commands are answered by a
question mark "?". Each command and each answer must be
↵
confirmed using (=<ENTER>)
The flow rate will be adjusted by the command Fxxxxx. Here is
xxxxx a 5-digit number (representing the flow rate in µl in ASCII
code using the numerals 0 to 9. The permissible range depends
on the pump head and the corresponding internal setting:
10 ml pump head:
50 ml pump head:
If the selected flow rate lies outside these limits, the command will
be ignored and the last entered flow rate will be maintained.
Controlling the pump via the serial interface enables a flow rate
selection resolution of 1µl/min, i.e. better than it can be achieved
via the keypad. Please keep in mind that this resolution cannot be
shown in the display.
The following Table 2 gives a communication example for the
10 ml pump head.
Input Reply
F200 OK
F2200 OK
F22000 ?
0 up to 9990
0 up to 50000
Description
Set the flow rate to 200 µl/min Command
correctly understood and executed
Set the flow rate to 2200 µl/min Command
correctly understood and executed
Set the flow rate to 22000 µl/min
Command not understood. Flow rate
remains at 2200 µl/min
External control