64
Remote I/O Communications Characteristics
Section 5-1
• Communications time per Slave:
Time required for each Slave. (See the following page.)
For a Slice I/O Terminal, this is the communications time for one of the
Communications Unit’s Slaves.
The “
Σ
(communications time per Slave)” is the total of the processing
times for the Slaves in the Network.
• SmartSlice processing time:
This processing time is 3.5 ms, only when there isn’t a single input,
output or mixed I/O Slave in the network with more than 8 bytes of I/O
data.
• Explicit message communications time:
0.11 × T
B
+ 0.6 [ms]
Added as a delay time when explicit message communications (send
or receive) are used.
T
B
: Constant (500 kbps: TB = 2; 125 kbps: TB = 4; 125 kbps: TB = 8)
• COS/Cyclic connection communications time:
(0.05 + 0.008 × S) × TB × n [ms]
Added as a delay time when COS/Cyclic connection is used for com-
munications.
S: Total size (bytes) of the COS/Cyclic connection’s input size and out-
put size.
n: Number of nodes for which COS/Cyclic connections occur at the
same time during one communications cycle.
• N: Number of Slaves
Communications
Time per Slave
T
RT-IN
and T
RT-OUT
The communications time per Slave is the time required for communications
to be performed with a single Slave.
The following equations show the communications time per Slave (T
RT
) for
each kind of Slave Unit. For a Slice I/O Terminal, the communications time per
Slave is the communications time per Slave with the DeviceNet Communica-
tions Unit. In the Slice I/O Terminal, 2 input words (4 bytes) are used for the I/
O Unit interface’s status flags, so those 4 bytes must be included in the total
when calculating the number of input bytes.
Output Slaves with up to 8
Bytes of Output
T
RT
= 0.016 × T
B
× S
OUT1
+ 0.11 × T
B
+ 0.07 [ms]
S
OUT1
: The number of Output Slave output words
T
B
: T
B
= 2 at 500 kbps; T
B
= 4 at 250 kbps; T
B
= 8 at 125 kbps
Input Slaves with up to 8
Bytes of Input
T
RT
= 0.016 × T
B
× S
IN1
+ 0.06 × T
B
+ 0.05 [ms]
S
IN1
: The number of Input Slave input words
T
B
: T
B
= 2 at 500 kbps; T
B
= 4 at 250 kbps; T
B
= 8 at 125 kbps
Mixed I/O Slaves with up
to 8 Bytes of I/O Words
T
RT
= 0.016 × T
B
× (S
OUT2
+ S
IN2
) + 0.11 × T
B
+ 0.07 [ms]
S
OUT2
: The number of Mixed I/O Slave output words
S
IN2
: The number of Mixed I/O Slave input word
T
B
: T
B
= 2 at 500 kbps; T
B
= 4 at 250 kbps; T
B
= 8 at 125 kbps
Input, Output, or Mixed I/O
Slaves with More than 8
Bytes of I/O Words
T
RT
= T
OH
+ T
BYTE-IN
× B
IN
+ T
BYTE-OUT
× B
OUT
[ms]
T
OH
: The overhead protocol
T
BYTE-IN
: The input byte transmission time
B
IN
: The number of input bytes
Summary of Contents for SMARTSLICE - 04-2008
Page 1: ...DeviceNet Communications Unit Cat No W454 E1 03 SmartSlice GRT1 DRT OPERATION MANUAL ...
Page 2: ...SmartSlice GRT1 DRT DeviceNet Communications Unit Operation Manual Revised April 2008 ...
Page 3: ...iv ...
Page 5: ...vi ...
Page 13: ...xiv ...
Page 27: ...8 Basic Operating Procedure Section 1 5 ...
Page 57: ...38 Unit Functions Section 2 3 ...
Page 101: ...82 DeviceNet Explicit Messages Appendix A ...
Page 113: ...94 Standard Models Appendix C ...
Page 115: ...96 Power Consumption Tables Appendix D ...
Page 117: ...98 I O Current Consumption Appendix E ...
Page 119: ...100 Glossary ...