SI-INTERBUS User Guide
45
Issue Number: 1
Sa
fety
Introd
Sup
Mec
El
G
A
Non
Vi
S
Contr
Di
S
F
CM
D tool
Glo
ssa
If all telegrams have been successful, the SI-Interbus will write the value 12553.9 to
Pr
1.021
.
The value written to the parameter will be scaled according to the number of decimal
places in the target parameter.
If there was a problem with writing the data to the parameter, e.g. the parameter does
not exist or the data is outside the range of the parameter, the ERR bit (b14) will be set
to 1.
Response (error)
Data word = 0x5663
Stamp Number = 6
Data byte = 0x63 = 99
8.1.7
Abort CT Single Word non-cyclic message
The internal state machine that controls the non-cyclic data transfer will only accept a
new telegram if it contains the next expected telegram stamp number (i.e. after
accepting telegram 2, the state machine will only respond to telegram 3. If any other
telegram stamp number is received, it will be ignored).
If an error occurs in the Interbus master controller that causes the telegrams to get out
of step, the master controller program should timeout, abort the message and reset the
non-cyclic state machine. This is done by setting the non-cyclic word to 0.
Request
Data word = 0x0000
Stamp Number = 0
Data byte = 0x00 = 0
8.1.8
Writing 16-bit parameters
Normally six telegrams would be required to access drive parameters using CT Single
Word non-cyclic data. When accessing 16-bit data only four telegrams are required.
If an attempt is made to read a 32-bit parameter from the drive, the parameter value will
be returned provided that the parameter value does not exceed signed 16-bit limits.
If the value is larger than a signed 16-bit value, the ERR bit will be set.
When writing data to a 32-bit parameter, the 16-bit data will be treated as a signed
16-bit data value. This limits the range that can be written to a 32-bit parameter.
Bit
b15 to b12
b11 to b8
b7 to b4
b3 to b0
Value
0101
0110
0110
0011
Bit
b15 to b12
b11 to b8
b7 to b4
b3 to b0
Value
0000
0000
0000
0000
