MKS PR4000 CONTROLLER driver for labview 8.6

Question

Hello BZajec,
Thanks for your reply.
I have set up the instrument via null modem (crossed) RS232 cable and have communicated with the instrument via hyperterminal in Microsoft XP. The only command to which I have had a response is 'v' which has returned 'PR41413602' and what is I think the instrument ID.
I have tried sending the command 'AV1' but I get no response.
I am very unclear from the PR4000 manual as to what the command syntax is.
Also I have tried running one of the PR4000 Labview Vi's. I am having a VISA problem which I don't know how to solve. Are you able to help me with this. (Please see attachment for screenshot of the problem.)
Also I have the latest vesion of Labview (9) and I cannot run your vi because it is an earlier version. Could you please tell me which version you are running?
Thanks for you help,
Nevica

Answer 1

Hello everybody !
It took me some days to figure out how to control the PR4000 single channel (PR4000S).
The commands are written in ASCII but very strangely. For example, you want to send "update all values" to set the setpoint.
In the manual the command is :
0x21 @cmd Setpoint.
You have to send everything in ASCII. 0x21 is "!" but as there are some unprintable characters I will write it (0x21)ASCII.
@cmd is (0x60)ASCII (`) if you want the setpoint off and (0x42)ASCII (B) if you want the setpoint on.
What is impossible to understand from the manual is that the ASCII codes you send for the setpoint are not the ASCII translation of the setpoint. It is a modified value.
You have to change your setpoint value (float=sgl) to ASCII. You have 4 bytes. Then you change these for bytes to binary. The you cut the last two bits. To have 8-bit bytes, you have to send the missing two bits in the header. You fullfill the setpoint bits with a 1 and the parity and you have SETPOINTMODIF (4bytes)
The header is actually made of the missing bits of the following bytes.
header2(b7 b6 b5 b4 b3 b2 b1 b0) SPByte3 SPByte 2 0x0  header1(b7 b6 b5 b4 b3 b2 b1 b0) SPByte1 SPByte 0 0x0
In all the commands, Byte 1 is 0x0 ! So bits 0 and 1 of the header are always 0
bits 2 and 3 of header 1 are the "missing bits" of your setpoint Byte 0
bits 4 and 5 of header 1 are the "missing bits" of your setpoint Byte 1
bits 2 and 3 of header 2 are the "missing bits" of your setpoint Byte 2
bits 4 and 5 of header 2 are the "missing bits" of your setpoint Byte 3
You fullfill the bits 6 and 7 of your header with the parity
Then you send all your string :
(0x21)ASCII (0x60)ASCII (head2)ASCII (SPMODIFB3)ASCII (SPMODIFB2)ASCII (0x0)ASCII (head1)ASCII (SPMODIFB1)ASCII (SPMODIFB0)ASCII (0x0)ASCII (Carriage return)ASCII
The guy who invented that should be totally crazy...
As a reward, a VI (LV7.1) to set the setpoint and read the actual value (on COM1)