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97
I/O Communication Characteristics
Section 3-5
3-5-3
Supported Data Types
The CS1/CJ1W-PRM21 PROFIBUS Master Units perform an interface func-
tion between a PROFIBUS network and the CS1/CJ1 PLC CPU. On both
sides of the interface different formats for data and data storages are used.
To ensure that I/O data transferred through the interface can be used on both
sides of the interface without additional formatting, the CS1/CJ1W-PRM21
PROFIBUS Master Units perform the necessary data formatting. This ensures
that I/O data in the PLC CPU memory can be processed by standard PLC
Instructions, and that the I/O data transferred to / from the PROFIBUS DP
slaves over the network is compliant with the PROFIBUS DP definitions.
The table below lists the I/O data formats supported by both the PROFIBUS
network and PLC CPU.
Data Type
Size
[bytes]
PROFIBUS DP
CS/CJ-series PLC
Single 8-bit Integer
signed/unsigned
1
Supported.
Data is transmitted on a byte-by-byte
basis.
Not supported
Minimum is 16-bit words. Two bytes will
be formatted in one word. Words con-
taining odd bytes will be padded with
zeros.
Single 16-bit Integer
signed/unsigned
2
Supported.
Data is transmitted on a Most-Signifi-
cant-Byte First basis.
Supported.
Single 16-bit integers are transferred to
memory words in PLC memory.
Single 32-bit Integer
signed/unsigned
4
Supported.
Data is transmitted on a Most-Signifi-
cant-Byte First basis.
Supported.
Data is stored with the Least-Significant-
Word at the lowest address.
Floating point
4
Supported.
Data is transmitted on a Most-Signifi-
cant-Byte First basis.
Supported.
Data is stored with the Least-Significant-
Word at the lowest address.
Visible string
--
Supported.
Length of string is fixed by I/O configura-
tion. Data is transmitted on a left-to-right
basis (i.e. first character is transmitted
first).
Supported.
First characters are stored at the lowest
address. String is padded with a zero
byte or a zero word, depending on the
number of characters.
Byte string
--
Supported.
Length of string is fixed by I/O configura-
tion. Data is transmitted on a left-to-right
basis (i.e. first character is transmitted
first).
Supported.
First bytes are stored at the lowest
address. String is padded with a zero
byte or a zero word, depending on the
number of characters.
Date / Clock time
7
Supported.
Date/Time format contains absolute time
with respect to start of century. Date/
Time is coded in individual bytes.
Not Supported.
Date/Time format is transferred to PLC
memory as string of words.
Time of day
6
Supported.
Time of day format contains time since
midnight.
Not Supported.
Time of day format is transferred to PLC
memory as string of words.
Time difference
6
Supported.
Time difference format is the same as
Time of day format, but contains a time
difference.
Not Supported.
Time difference format is transferred to
PLC memory as string of words.