Installation manual

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4
4.4
Characteristics (continued),
description
Modicon TSX Micro
automation platform 0
Uni-Telway bus
The Uni-Telway bus cycle time depends on:
b The number of devices polled (datalink addresses).
b The data rate.
b The turnaround time of each device.
b The number, length and type of messages.
BCT = Bus Cycle Time, is the interval between two polls from the same device.
The curves opposite give the Uni-Telway cycle time as a function of the number of
slaves operating at 9.6 Kbit/s or 19.2Kbit/s, with a typical turnaround time of 5 ms per
device (excluding messages).
The following table shows the time to be added (in ms) to obtain the true BCT value
as a function of the traffic (N = Number of usable characters):
In a distributed control system architecture the application-to-application response
time depends not only on the communication system, but also on:
b The processing times of the message source and destination devices.
b The degree of asynchronism between the bus and processor cycle times.
This response time must be evaluated by the designer of each application according
to the devices which are connected.
The processing time of a device may vary from one to two cycle times depending on the
degrees of asynchronism.
TSX Micro/Premium PLCs provide various ways of connecting to the Uni-Telway
bus.
1 By integrated TSX Micro/Premium processor or Atrium coprocessor port
The AUX port (2) (8-way mini-DIN) has one non-isolated RS 485 serial link
channel (maximum distance 10 m).
2 By TSX SCY 21601 integrated port for Premium PLC or Atrium coprocessor
This module has one Half-duplex isolated RS 485 serial link channel, which is
multiprotocol, including Uni-Telway.
3 Via multiprotocol PCMCIA card
A slot on the TSX 37 21/22/Premium PLC processors, the Atrium coprocessor
and the TSX SCY 21601 module (3) accepts the following multiprotocol cards:
v TSX SCP114 PCMCIA card
Isolated RS 485/RS 422 link. This type of card corresponds to the Uni-Telway
standard.
v TSX SCP 111 PCMCIA card
Non isolated RS 232D link. This type of card can be used for direct point-to-point
links or via Modem.
v TSX SCP 112 PCMCIA card
20 mA current loop link. This type of card is used for a multidrop link (2 to 16 devices)
and requires a c 24V external power supply.
(1) N = Number of usable characters corresponding to the messages to be exchanged.
(2) TER port for TSX 37 05/08/10 PLC.
(3) This slot can also accept the TSX FPP 20 PCMCIA card for Fipway networks, or the
TSX JNP 112/114 PCMCIA card for JNet networks.
Performances
Time (ms)
Exchanges at 9.6 Kbit/s at 19.2 Kbit/s
Master to slave 24 + 1.2 N (1) 17 + 0.6 N (1)
Slave to Master 19 + 1.2 N (1) 12 + 0.6 N (1)
Slave to slave 44 + 2.3 N (1) 29 + 1.15 N (1)
14 8 121620242
7
1
00
2
00
3
00
4
00
1
2
BCT
(
ms)
1 = 9.6 Kbit/s
2 = 19.2 Kbit/s
Event Report
CT1 CT1 CT1 CT1
CT2 CT2
Action
Device 1
Device 2
BCT BCTUni-Telway bus
B
CT = Uni-Telway bus cycle time
C
T1 = Device 1 bus cycle time
C
T2 = Device 2 bus cycle time
Description
TSX Micro/Premium PLCs
T
SX Micro
C
onnections:
p
age 4/62
References:
page 4/63
1
2
3
TSX SCY 21601
P
remium
Courtesy of Steven Engineering, Inc. ● 230 Ryan Way, South San Francisco, CA 94080-6370 ● General Inquiries: [phone] ● www.stevenengineering.com
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