INFICON SKY CDGxxxD (RS232C) - Manual (Page 4)

4
tira49e1-a (2010-02) RS232C.cp
Bit No. Definition
0 RS232 synchronization error
1 Incorrect command, e.g. inadmissible address (syntax error)
2 Inadmissible read command
3 SP1 status
4 SP2 status
5 Not used
6 Not used
7 Extended error set ( → Read command "Extended Error
L-Byte and H-Byte")
No bit set → value = 0x00 = no error set
Errors are only recorded in the error bytes as long as they persist, except for
RS232 interface errors. Errors are not acknowledged.
RS232 errors are signaled by the "toggle bit", i.e. when an RS232 error occurs, the
"toggle bit" is not inverted. For checking the status of the "toggle bit", a read
operation is required, which also allows to read the error byte for detailed error
analysis.
If an "extended error" is set, it has to be read as variable by means of the "read
command" (
→ table "Variables for bytes No. 2 and 3"). After the read operation, the
variable is automatically erased.
The pressure is calculated from bytes 4 and 5 of the send string (decimal
presentation).
×a
p =
b
×F.S.R._Mantissa×10 (F.S.R._Exp)
Parameter Description
p Pressure value in selected pressure unit (→ Parameter a)
Pressure measurement data, composed of "low and high
byte" (16 bit value) and converted into decimal format
F.S.R._Mantissa F.S.R. factor according to "Sensor type" variable, which
has to be read separately ( → "Read command")
F.S.R._Exp F.S.R. exponent according to "Sensor type" variable, which
has to be read separately ( → "Read command")
a Conversion factor for pressure units other than "Torr".
Torr: a = 1.00
mbar: a = 1.3332
Pa: a = 133.32
b Factor for resolution
Page No. 1) b Output signal
2 32000 10.24 V
3 32000 10.24 V
4 32767 10.00 V
1) → 3, tabel "Structure of send string", byte no. 1
Error byte
(byte No. 3)
Error handling
Calculation of pressure value
Conversion formula
(byte No. 4 and 5)