32
SI-INTERBUS User Guide
Issue Number: 1
8
Non-Cyclic data
The non-cyclic data channel provides a method for the Interbus master controller to
read from or write to any parameter within the drive or option module. This channel can
be used for single infrequent data transfers, or uploading and downloading parameter
sets to or from a particular node.
The SI-Interbus provides three non-cyclic data formats, plus the option to disable non-
cyclic data.
•
CT Single Word format (mode 1, see
)
•
PPO 4 Word format (mode 2, see
)
•
Peripheral Communications Protocol V2.0 (mode 3, see
Peripheral Communications Protocol V2.0
)
The non-cyclic mode is indicated by the first digit in the value of Pr
MM.005
(
Interbus Data format
) as shown in the following table.
Table 8-1 Non-cyclic modes
8.1
Mode 1 - CT Single Word mode
The CT Single Word (mode 1) uses one cyclic channel for non-cyclic data. The non-
cyclic sub-protocol requires a specific sequence of 4 (16-bit parameters) or 6 (32-bit
parameters) telegrams to implement the parameter access. Each non-cyclic word or
telegram is split into 2 bytes to implement the sub-protocol, with the high byte containing
the control codes for each telegram, and the low byte containing the data for each
telegram.
Non-cyclic Mode
Data Format
(Pr MM.005)
Description
Disabled
0xx
Non-cyclic data disabled
CT Single Word
1xx
CT Single Word non-cyclic (mode1).
Uses 2 cyclic data words if data compression is
disabled or 1 cyclic data word if data compression is
enabled (Pr
MM.034
).
Pr
MM.010
and Pr
MM.020
will be set to the value 6150
and any existing mappings will be moved down one
place.
PPO 4 Word
2xx
PPO 4 Word non-cyclic data (mode 2).
Uses four cyclic data words.
Pr
MM.010
and Pr
MM.020
will be set to the value 6151
and any existing mappings will be moved down one
place.
PCP V2.0
3xx
Peripheral Communications Protocol (PCP) V2.0.
Existing mapping configuration will not be affected.
If cyclic data compression is disabled (Pr
MM.034
= Off), the CT Single Word non-cyclic
channel will be 32 bits wide, i.e. uses 2 words, and data must be transferred on the low
word. If cyclic data compression is enabled (Pr
MM.034
= On), the CT Single Word non-
cyclic channel will revert to 16 bits and only use 1 word.
NOTE
NOTE
