111
Remote I/O Communications Characteristics
Section 6-1
Communications Time Per Slave:
This is the communications time required for a single Slave (see below).
“
Σ
(Communications time per Slave)” represents the total of the “Commu-
nications time per Slave” for all the Slaves in the network.
High-density Unit Processing Time:
3.5 [ms]
This is added if there are any Slaves in the network that use at least 8 bytes
for input, output, or both.
Explicit Message Processing Time:
(0.11
×
T
B
)
×
n [ms]
Only added when explicit communications (transmission or reception) are
performed.
n: Number of explicit messages that occur at the same time during one
CPU Unit cycle (including transmission and reception).
T
B
= Baud rate factor
(T
B
= 2 for 500 kbps, T
B
= 4 for 250 kbps, and T
B
= 8 for 125 kbps)
COS/Cyclic Connection Communications Time [ms]:
{(0.05 + 0.008
×
S)
×
T
B
}
×
n [ms]
S: Total input and output size (in bytes) for COS/Cyclic connection.
T
B
= 2 for 500 kbps, T
B
= 4 for 250 kbps, and T
B
= 8 for 125 kbps
n: Number of nodes for COS/Cyclic connections that are used at the
same time in one communications cycle.
N: Number of Slaves
Communications Time/
Slave
The communications time per Slave is the time required for communications
with a single Slave. Use the following equations to calculate the communica-
tions time/Slave (T
RT
) for each kind of Slave.
Output Slaves with less than 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
:
Baud rate factor
(T
B
= 2 for 500 kbps, T
B
= 4 for 250 kbps, and T
B
= 8 for 125 kbps)
Input Slaves with less than 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
:
Baud rate factor
(T
B
= 2 for 500 kbps, T
B
= 4 for 250 kbps, and T
B
= 8 for 125 kbps)
Mixed I/O Slaves with less than 8 Bytes each of Input and Output
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 words
T
B
:
Baud rate factor
(T
B
= 2 for 500 kbps, T
B
= 4 for 250 kbps, and T
B
= 8 for 125 kbps)
Slaves with more than 8 Bytes of Input or Output or both
T
RT
= T
OH
+ T
BYTE-IN
×
B
IN
+ T
BYTE-OUT
×
B
OUT
[ms]
Summary of Contents for DeviceNet 3G8F7-DRM21-E
Page 1: ...OPERATION MANUAL Cat No W381 E1 02 3G8F7 DRM21 E DeviceNet PCI Board ...
Page 2: ...3G8F7 DRM21 E DeviceNet PCI Board Operation Manual Revised July 2005 ...
Page 3: ...iv ...
Page 5: ...vi ...
Page 29: ...12 Preparation for Operation Section 1 8 ...
Page 67: ...50 PC Watchdog Timer Management Function Section 3 11 ...
Page 115: ...98 Maintenance API Functions Section 4 7 ...
Page 131: ...114 Remote I O Communications Characteristics Section 6 1 ...
Page 145: ...Index 128 ...
Page 147: ...130 Revision History ...