Spezialelektronik GmbH
iseg Spezialelektronik GmbH Email: sales@iseg-hv.de Tel ++ 49 (0) 351 / 26 996 - 0
Bautzner Landstr. 23 http://www.iseg-hv.de Fax ++ 49 (0) 351 / 26 996 - 21
D - 01454 Radeberg/ Rossendorf 13
5. Description of the RS232-Interface
The RS232-Interface is also connected to a SubD-connector on the rear side of the unit. Before
working with RS232-Interface the menu„F09“ „r232“ has to be selected.
As soon as the device receives according commands via the interface the device is under remote
control and the LED „REM“ is flashing.
Pushing „LOCAL“ again the device is back in manual mode and „HV-OFF“ . The receipt of
commands activates the devise again under remote control.
The data transfer is character oriented, while the synchronization in direction "Computer to HV PS
unit” (Input direction) is made by echoes. The transfer direction “HV-PS to computer“ (Output
direction) is free running.
It is able to disable the Echo function since software release 4.04:
1
st
On control panel via menu F13 “ECHO”.
2
nd
Common command via interface, see chapter 7.3.
Standard setting ex works is „Echo ON“.
Programming information:
The delay time between write and read instruction has to be at least 35ms (without echo) or 70ms
(with echo).
Example: Write(“Status,u”) write instruction,
wait the delay time (35 ms without Echo/ 70ms with Echo),
send read instruction
Read(String) Answer: U, RANGE=x.xxx kV, VALUE=x.xxxx kV
The unit need a time between setting new values for voltage or current control and reading out of the
updated actual values for output voltage or current.
This minimal waiting time is given through the rate of change of output voltage (according to the
command “ramp speed”) + 130ms.
The RS232-Interface is set to 9600 Bit/s, 8 Bit/character, no parity, 1 Stop-Bit.
The electrical transfer is working indirectly coupled via RxD and TxD related to GND. The pin
assignment of the D-Sub 9 is in the following table .
The cable connection to the computer is 1:1 (no zero modem-cable !). If no 9-pole cable is available ,
then the bridges mentioned in the table have to be made.
Signal HV-PS PC PC Connection
RS 232 DSUB9 Intern DSUB9 DSUB25 3-pol. cable
RxD 2 2 3
TxD 3 3 2
GND 5 5 7
4
─┐
4 20
─┐
6
─┤
6 6
─┤
8
─┘
8 5
─┘
Syntax
The transfer of commands works in ASCII-code. The end of a set of characters is made by
<CR><LF> ($0D $0A or 13 10). On input side the leading zeros are useless, the output side is in
fixed format without leading zero.