44 45
The meaning of B
1
and B
2
is:
B
2
bit 0 green LED (1: ON; 0: OFF)
B
2
bit 1,2 red LED (bit 2 = 0 and bit 1 = 0: LED is OFF;
bit 2 = 1 and bit 1 = 0: LED is fixed
ON; bit 2 = 1 and bit 1 = 1: LED blinks)
B
2
bit 3 free for future use (and set to 0)
B
2
bit 4 free for future use (and set to 0)
B
2
bit 5 free for future use (and set to 0)
B
2
bit 6 free for future use (and set to 0)
B
2
bit 7 free for future use (and set to 0)
B
1
bit 0 free for future use (and set to 0)
B
1
bit 1,2 setup mode (bit 2=0 and bit 1=0: not in setup
mode; bit 2=1 and bit 1=0: setup mode, view
only; bit 2=1 and bit 1=1: setup mode, unlocked)
B
1
bit 3 calibration mode with device unlocked
(1: yes, 0: no)
B
1
bit 4 setup updated (set to 1 after a device power-up or
a device reset or a change in setup made through
the instrument keyboard; reset to 0 after receiving
a GET command)
B
1
bit 5 calibration made (set to 1 after a device power-up
or whatever complete calibration; reset to 0 after
receiving a CAR command)
B
1
bit 6 hold mode (1: ON, 0: OFF)
B
1
bit 7 free for future use (and set to 0)
The NNCAR request produces the following answer:
1) Instrument configured for pH:
If pH is not calibrated: “NN<STX>0<ETX>”
If calibration has been performed: “NN<STX>1 date time offset
slope1 slope2 buf1 buf2 N<ETX>”
The items in italic are separated by blank spaces and have the
following formats:
date ddmmyy (“020498” for April 2, 1998)
time hhmm (“1623” for 4:23 pm)
offset ASCII string for a float (example: “-0.2”)
slope1 ASCII string for a float (example: “62.5”)
slope2 ASCII string for a float (example: “60.4”)
The “NNSET...” and “NNGET...” commands when used for
password items, baud rate, F.00 and F.10 items, are answered
with “NN<CAN>”.
As soon as the instrument realizes that a command has been
received, it sends one of the following answers:
1) “NN”, ACK (char 0x06) if the instrument recognizes the set
command and performs the requested task;
2) “NN”, STX (char 0x02), DATA, ETX (char 0x03) if the re-
ceived command is a request of data;
3) “NN”, NAK (char 0x15) if the instrument does not recog-
nize the command or if the command syntax is wrong;
4) “NN”, CAN (char 0x18) if the instrument can not answer
to the request (because the given general password is
wrong, etc.)
The “NN” in the front of the answer is the Instrument
ID (“00” to “99”).
The time-out for the above answers is:
1) answer to “STS”, “PHR”, “MVR”, “TMR”, “AER” commands:
30 ms @ 19200 or 9600 bit/s, 40 ms @ 4800 bit/s, 60 ms
@ 1200 bit/s (for the complete answer, from STX to ETX).
2) answer to other commands: 2s (for the first character of the
answer).
The minimum delay between the last received and the first
sent character is 15 ms to allow the master to set itself into
receiving mode.
Here are descriptions of the answers format (for setup item
request see above):
The NNMDR request produces the following answer:
“NN<STX>FP504910VV--ABCD<ETX>”
where VV is the firmware version, e.g. ”10” for 1.0 and ABCD
is a special code used by HI 92500.
The NNPHR, NNMVR, NNTMR requests produce the fol-
lowing answer:
“NN<STX><ASCII string for a float>N<ETX>”.
The answer to the NNSTS command is:
“NN<STX>C
1
C
2
C
3
C
4
<ETX>”
where C
1
C
2
are the ASCII representation of byte B
1
described
below (e.g. B
1
= 0xF3 C
1
= “F”, C
2
= “3”), C
3
C
4
are the
ASCII representation of byte B
2
described below (e.g. B
2
= 0x1D
C
3
= “1”, C
4
= “D”).
