Hanna Instruments HI 720 Series - Manual (Page 31)

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the first HI 92500 software version compatible with the firmware, even if it may not
be able to exploit all the features of the firmware, e.g. “34” for 3.4; CD is the first HI
92500 software version fully compatible with this firmware, e.g. “45” for 4.5.
The HOP request produces the following answer:
“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
de-
scribed below (e.g. B
2
= 0x1D, C
3
= “1”, C
4
= “D”).
The meaning of B
1
and B
2
is:
B
2
bit 0 optional relay 2 (1: available; 0: not available)
B
2
bit 1 Digital Transmitter input (1: available; 0: not available)
B
2
bit 2 PID control (1: available; 0: not available)
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 serial port (1: available, 0: not available)
B
1
bit 1 serial port type (0: RS485)
B
1
bit 2 analog outputs (1: available, 0: not available)
B
1
bit 3 second analog output (1: available, 0: not available;
no meaning if bit 2 = 0)
B
1
bit 4 optional relays 3 and 4 (1: available, 0: not available)
B
1
bit 5 hold digital output (1: available)
B
1
bit 6 free for future use (and set to 0)
B
1
bit 7 relay 1,2,3,4 type (0: electromechanical)
The ECR request produces the following answer:
“NN<STX><ascii string for measure>S<ETX>”
where <ascii string for measure> contains the conductivity or TDS or concen-
tration measure displayed on the LCD, followed (without any space) by the mea-
sure unit (μS, mS, ppm, ppt or %). When the measure is out of range, all digits
are replaced with “>” character.
To distinguish between a TDS or concentration measure, request G.00 setup
item. “S” means “status” and can be equal to:
• “A”, i.e. control and alarm are ON
• “C”, i.e. control is ON and alarm is OFF
• “N”, i.e. control is OFF
For all items with a fixed set of choices, blank spaces on the left of the value
displayed are replaced with “*” (as many “*” characters are needed to reach the
maximum string length, which is for example 3 for item C.57).
Blanks must be put on the tail for all items in order to have always a total length
of 6 characters (see the setup table for item lengths).
The same parameter format used for setup item setting is also used for setup
item getting (i.e. when a “GETCNN<CR>” command is received from the PC,
the reply “NN<STX>P
1
P
2
C
1
C
2
C
3
C
4
<ETX>” is sent back).
To perform a “SETCNN...” command, the general password has to be sent in
advance through the “PWD...” command. See above for the password effective-
ness time-out. Some special setup items (see “Setup” section) can not be set
through RS485 commands. Note that no validity check of the sent item value is
performed upon reception of a “SETCNN <CR>” command. This check is done
by th
e HI 92500 software and must also be done by different programs.
The “SET...” and “GET...” commands when used for password items, b.50 item
and all items of the “Communication” group are answered with “NN<CAN>”.
As soon as the process controller realizes that a command has been received, it
sends one of the following answers:
1) “NN”, ACK (char 0x06) if the process controller recognizes the set command
and performs the requested task
2) “NN”, STX (char 0x02), DATA, ETX (char 0x03) if the received command is a
request of data
3) “NN”, NAK (char 0x15) if the process controller does not recognize the com-
mand or if the command syntax is wrong
4) “NN”, CAN (char 0x18) if the process controller can not answer to the re-
quest (e.g. the current process model does not support the request, the given
general password is wrong, etc.)
For RS485, the minimum delay between the last received and the first sent char-
acters is 15 ms to allow the master to set itself into receive mode.
The “NN” in the front of the answer is the Process ID (00 to 99).
Here are descriptions of the answer format (for setup item request see above):
The MDR request produces the following answer:
“NN<STX>FP720XYZVV--ABCD<ETX>”
where VV is the firmware version, e.g. ”10” for 1.0; XYZ are the three model
digits, e.g. XYZ=224 for dual setpoint, PID control, dual analog output; AB is