192
Remote I/O Communications Characteristics
Section 6-1
• For details about the communications time required for 1 Slave refer to
page 192. For the MULTIPLE I/O TERMINAL, it equals the communica-
tions time required for 1 Slave Unit of the Communications Unit.
Σ
(com-
munications time per Slave) is the total of the communications times for all
the Slaves in the network.
• Multiple Units processing time = 3.5 (ms). It is to be added only if there is
a Slave where the input or output exceeds 8 bytes.
• Explicit message processing time = 0.11
×
T
B
+ 0.6 (ms). It is to be added
only when explicit message communications are executed. T
B
is a fixed
value (At 500 kbps = 2, 125 kbps = 4, 125 kbps = 8).
• N = Number of Slaves
Communications Time per
Slave
The communications time per Slave is the communications time required for a
single Slave. The formula for calculating the communications time per Slave
(T
RT
) for different types of Slave is shown below. For the MULTIPLE I/O TER-
MINAL, it will be the communications time per Slave of the Communications
Unit. With the MULTIPLE I/O TERMINAL, 2 input words (4 bytes) are used for
notifying the status of I/O Unit interfaces. This must be included as the num-
ber of bytes when making calculations.
Output Slave with 8 Bytes of Output or Less
T
RT
= 0.016
×
T
B
×
S
OUT1
+ 0.11
×
T
B
+ 0.07 (ms)
S
OUT1
: Number of output words for the Output Slave
T
B
:
At 500 kbps = 2, 250 kbps = 4, 125 kbps = 8
Input Slave with 8 Bytes of Input or Less
T
RT
= 0.016
×
T
B
×
S
IN1
+ 0.06
×
T
B
+ 0.05 (ms)
S
IN1
:
Number of input words for the Input Slave
T
B
:
At 500 kbps = 2, 250 kbps = 4, 125 kbps = 8
Mixed I/O Slave with 8 Bytes of Both Input and Output or Less
T
RT
= 0.016
×
T
B
×
(S
OUT2
+ S
IN2
) + 0.11
×
T
B
+ 0.07 (ms)
S
OUT2
: Number of output words for the Mixed I/O Slave
S
IN2
:
Number of input words for the Mixed I/O Slave
T
B
:
At 500 kbps = 2, 250 kbps = 4, 125 kbps = 8
Slave 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)
T
OH
:
Protocol overhead
T
BYTE-IN
:
Input byte transmission time
B
IN
:
Number of input bytes
T
BYTE-OUT
: Output byte transmission time
B
OUT
:
Number of output bytes
If there are no Output Slaves, use 0 as the value of B
OUT
. If there are no input
Slaves, use 0 as the value of B
IN
.
Communication speed
T
CH
T
BYTE-IN
T
BYTE-OUT
500 kbps
0.306 ms
0.040 ms
0.036 ms
250 kbps
0.542 ms
0.073 ms
0.069 ms
125 kbps
1.014 ms
0.139 ms
0.135 ms
Содержание DRT1-COM
Страница 1: ...OPERATION MANUAL Cat No W348 E1 05 DRT1 COM GT1 Series DeviceNet MULTIPLE I O TERMINAL ...
Страница 2: ...DRT1 COM GT1 Series DeviceNet MULTIPLE I O TERMINAL Operation Manual Revised May 2003 ...
Страница 3: ...iv ...
Страница 5: ...vi ...
Страница 13: ...xvi EC Directives 6 3 Keep DeviceNet communications cables as short as possible and ground to 100 Ω min ...
Страница 232: ...Authorized Distributor Cat No W348 E1 05 Note Specifications subject to change without notice Printed in Japan ...
Страница 233: ...DRT1 COM GT1 Series DeviceNet MULTIPLE I O TERMINAL Cat No W348 E1 05 OPERATION MANUAL ...