Operation
30
GA09420_002_C0 – (2016-10) –
Leybold
Synchronization
Synchronization of the master is achieved by testing three bytes:
Byte No Function
Value
Comment
0
Length of data string
7
Set value
1
Page number
5
(For ITR 90)
8
Check sum of bytes No 1 … 7
0 … 255 Low byte of check
sum
1)
1)
High order bytes are ignored in the check sum.
Status byte
Bit 1
Bit 0
Definition
0 0
Emission
off
0 1
Emission 25
μ
A
1
0
Emission 5 mA
1 1
Degas
Bit 2
Definition
0
1000 mbar adjustment off
1
1000 mbar adjustment on
Bit 3
Definition
0
⇔
1
Toggle bit, changes with every
string received correctly
Bit 5
Bit 4 Definition
0
0
Current pressure unit mbar
0
1
Current pressure unit Torr
1
0
Current pressure unit Pa
Bit 7
Bit 6 Definition
x x
Not
used
Error byte
Bit 3
Bit 2
Bit 1
Bit 0
Definition
x x x x
Not
used
Bit 7
Bit 6
Bit 5
Bit 4 Definition
0 1 0 1
Pirani
adjusted
poorly
1 0 0 0
BA
error
1 0 0 1
Pirani
error
Software version
The software version of the transmitter can be calculated from the value of byte 6
of the transmitted string according to the following rule:
Version No = Value
Byte 6
/ 20
(Example: According to the above formula, Value
Byte 6
of 32 means software ver-
sion 1.6)
