10
…8
COMMUNICATION
…8.4
Communication Examples
11
W
STX
11
End of text
e) Command –
STX
W11A170
E
ETX
A1 70
Command understood
Alarm A setting is 70
Reply –
11LA70
ACK
LA 70 ETX
Write
to
70
Alarm A trip point
Controller number eleven
'Write' command
Start of text
ACK
Controller number eleven
05
W
STX
05
End of text
f) Command –
STX
W05L21
E
ETX
03
Command not understood
Error code 3
Reply –
0503
N
NAK
L2
1 ETX
Relay 2
energised
Relay 2 state
Controller number five
'Write' command
Start of text
NAK
Controller number five
i.e. 'L2' in the original command is not
a recognised 'Write' parameter. The
'L2' mnemonic can only be used with
the 'Read' command.
Self-tune state
(0 = off, 1 = on)
Auto/Manual state
(0 = auto, 1 = manual)
Set Point type
(0 = local, 1 = second)
Security level 1 access
(0 = no access, 1 = access)
Security level 2 access
(0 = no access, 1 = access)
Power failure status
(0 = no power failure, 1 = power failure)
Process variable failure
(0 = no failure, 1 = failure)
Remote set point failure
(0 = no failure, 1 = failure)
Position feedback failure
(0 = no failure, 1 = failure)
11 10 9 8 7 6 5 4 3 2 1 0
MSB
LSB
Unacknowledged alarm
(0 = no alarms unacknowledged,
1 = alarms unacknowledged)
Alarm 2 relay state
(0 = relay off, 1 = relay on)
Alarm 1 relay state
(0 = relay off, 1 = relay on)
Fig. 8.7 Instrument Status
