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M’Ax User Guide 89
Issue Number: 4
Repeat the previous request for a parameter value
Host to Drive
A Drive will respond to this message only if the previous read-command
issued by the host was addressed to and understood by the Drive.
Otherwise, the host must send a new read-command.
Request the value of the next parameter in the menu
Host to Drive
A Drive will respond to this message only if the previous read-command
issued by the host was addressed to and understood by the Drive.
Otherwise, the host must send a new read-command.
Request the value of the previous parameter in the
menu
Host to Drive
A Drive will respond to this message only if the previous read-command
issued by the host was addressed to and understood by the Drive.
Otherwise, the host must send a new read-command.
Change the value of a parameter (write-command)
Host to Drive
Example
Group 4, Unit 6
Set parameter
1.17 at +76.4
Host sends:
EOT 4466 STX 0117 +076.4 ETX $
Acknowledge response to a command
Drive to host
When a write-command has been understood and performed by the
Drive:
If a write-command has not been understood (hence not been
performed) by the Drive:
Sending a re-write command
Host to Drive
The re-write command can be used for changing the value of any
parameter in the last Drive that was addressed by the host in a write-
command. The re-write command eliminates the need to include the
address in the message. This function can be used irrespective of
whether the Drive had understood the write-command.
Calculating the block checksum
Calculation of the BCC is performed on the binary number for the hex
code of each character that follows the STX character in a message.
The calculation applies, in turn, an exclusive-OR (XOR) logic function
between each binary number and the XOR result from the previous
number.
Procedure
To calculate the BCC for a write-command that is to set parameter 1.21
Preset reference 1 at –34.5RPM in a Drive whose address is 1.2.
The message to be calculated is as follows:
The first character of the BCC calculation is
0.TheASCIIcodeforthis
character (48) is
0011 0000 in binary format. This binary number is then
taken as a starting or result value. The next character is
1 (0011 0001 in
binary). The exclusive-OR (XOR ) operator is now applied to this number
In conjunction with the previous result. This yields a new result of
0000
0001
. The process is repeated as follows to produce a final result:
The final binary value is used for the BCC, provided that its decimal
equivalent is greater than
31 (ASCII characters from 0 to 31 areusedas
control codes). If it is less than
32, 32 must be added.
In this example, the decimal equivalent of
0011 0000 is 48 which
exceeds
31; 48 is then used for defining the BCC character. ASCII code
48 is the character 0 (zero).
The complete message will be as follows:
C.7 Making new values take effect
Parameters that are indicated by the letter R in Chapters M0 to M13
require the Drive to be reset for the new value(s) to take effect. (New
values given to other parameters take effect immediately.)
To reset the Drive, send a write-command to set parameter
10.38 at 100.
When using 10.38 to 100 to reset the Drive after certain
function (i.e. PrXX.00 to either 1233, 1244 or 1255, or
setting Pr0.50 to either boot1, boot2, no or Prog), the
Drive will not send back an ack signal to the host. It can
also take 15 seconds for the flash memory to be
updated before the next function can be carried out.
NAK
ACK
BS
EOT G G U U STX m1 m3 p1 p2 ...
... v1 ... vn ETX BCC
ACK
NAK
or
EOT (depending on the reason)
STX m1 m2 p1 p2 v1 ... vn ETX BCC
XOR truth table
ABResult
00 0
01 1
10 1
11 0
EOT1122STX0121STX...
Excluded from the calculation
...0121-34.5ETX
Included in the calculation
Character Binary value XOR result
0 0011 0000 (0011 0000)
1 0011 0001 0000 0001
2 0000 0010 0011 0011
1 0011 0001 0000 0010
- 0010 1101 0010 1111
3 0011 0011 0001 1100
4 0011 0100 0010 1000
. 0010 1110 0000 0110
5 0011 0101 0011 0011
ETX 0000 0011 0011 0000
EOT1122STX0121STX...
...0121-34.5ETX0
CAUTION
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