STATUS SCIENTIFIC CONTROLS
Installation, Commissioning & Routine Gas Testing
FGD10A Oxygen / Toxic Gas Detector
TD18/002
Issue:
16
Change Note:
1904
Page 40
7.5. Reading a Variable
Send a read frame with the Variable ID to be read:
DLE
RD
var-
id
DLE
EOF
Csum
hi
Csum
lo
Byte
stuffing
Device response on success, where requested variable data < 255 bytes:
DLE
DAT
data-
len
data
DLE
EOF
Csum
hi
Csum
lo
Byte stuffing
Device response on failure:
DLE
NAK
reason
Where ‘reason’ is a single byte failure code, the meaning of which depends
on the device type, i.e.
Reason = 1, NotReadable,
Reason = 2, ReadOutOfRange
