參數(shù)資料
型號(hào)： PC-COM4
英文描述： PC(ISA)BUS I/O CARD
中文描述： 電腦（ISA）總線的I / O卡
文件頁(yè)數(shù)： 8/20頁(yè)
文件大小： 492K
代理商： PC-COM4
If you are designing your own systems implementation from scratch, you will be able to select
the appropriate type of communications standard for your system:
RS422 point-point is a good way of connecting two pieces of equipment together as the
differential communications system gives good noise immunity and the full duplex gives high
speed.
RS422 Multi-drop is suitable for systems where one piece of equipment is controlling a number
of other pieces of equipment in a master/slave type relationship. The full duplex nature of the
system provides for high speed communication. Be aware that the software must ensure that
no two transmitters are driving on to the bus at once. The line drivers have protection circuitry
in them to prevent damage occurring, but communications data will be lost.
RS485 is also a multi-drop configuration and is ideal for peer-peer networking or for systems
where cabling cost is large so there is advantages to be gained with a three wire system. Not
again that the software must ensure that only one transmitter is driving the communications
pair at once.
Configure links LK23-26 for the appropriate differential communications mode for channels A
and B.
Line Terminations
Differential communications pairs should be terminated to prevent reflections from either end
of the communications cables. Each pair should be terminated at each end of the wire run with
a resistance that matches the impedance of the cable.
The PC-COM4 is capable of terminating each of the differential pairs on channels A and B
using links LK19-22. Two types of termination network can be configured: line matching
terminators and pull apart resistors.
Line Matching Terminators
124 ohm resistors can be linked across each communications pair (see Links section). This will
be a fair match with twisted pair wiring. These should be configured on boards at either end of
the wiring run only.
Pull Apart Resistors
The PC-COM4 is also able to pull each line of a communications pair to either +5V or 0V
through a 4K7 resistor. This facility is primarily intended for use in RS422 multi-drop or RS485
systems to ensure that the communications pair floats to a known state when no transmitters
are active.
Normally, a communications pair would be pulled apart in the inactive state. This mimics the
condition where no character is being transmitted from the UART. It is however possible for the
PC- COM4 to pull the communications pair in either direction.
Care should be taken when using the pull-apart resistors in systems with multiple pieces of
equipment on the same pair as each fitted pull apart network will load the line driver devices.
Reduce the number of fitted resistor networks to prevent this causing problems.
If there are no pull-apart resistor networks fitted anywhere on a multi-drop communications
pair, it will be necessary for software to wait in excess of one character transmission time after
asserting the RTS signal before loading the first character into the UART transmit buffer. This
gives the receiving equipment time to clear any error character caused by a rogue start bit
when the line driver was enabled at the transmitter.
2192-09197-000-000
Page 8
J606 PC-COM4
CONTROL SYSTEMS
相關(guān)PDF資料
PDF描述
PC1231XNSZ PHOTOCOUPLER
PC123 European Safety Standard Approved Type Long Creepage Distance Photocoupler
PC123A DEVICE SPECIFICATION FOR PHOTOCOUPLER
PC123F European Safety Standard Approved Type Long Creepage Distance Photocoupler
PC1316 Dual Channel Audio Power Amplifier Dual Power Amplifier 2W 12V 10%
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
PCC-OST-E 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Sta 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Standard Connector, Connector Mounting:PCB, Connector Type:Thermocouple, No. of Contacts:2, Series:PCC, Thermocouple Type:E , RoHS Compliant: NA
PCC-OST-K 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Sta 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Standard Connector, Connector Mounting:PCB, Connector Type:Thermocouple, No. of Contacts:2, Series:PCC, Thermocouple Type:K , RoHS Compliant: NA
PCC-OST-T 制造商:Newport Electronics Inc 功能描述:CONNECTOR, For Use With:Standard Circuit Board, Accessory Type:Circuit Board Standard Connector, Connector Mounting:PCB, Connector Type:Thermocouple, No. of Contacts:2, Series:PCC, Thermocouple Type:T , RoHS Compliant: NA
PCCOV19001BK1 功能描述:機(jī)架和機(jī)柜配件 WIRE MANAGER COVER 1U RoHS:否 制造商:Bivar 產(chǎn)品:Rack Accessories 面板空間: 顏色:Black
PCCOV19003BK1 功能描述:機(jī)架和機(jī)柜配件 WIRE MANAGER COVER 2U RoHS:否 制造商:Bivar 產(chǎn)品:Rack Accessories 面板空間: 顏色:Black
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。

采購(gòu)需求

(若只采購(gòu)一條型號(hào)，填寫一行即可)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

發(fā)布成功！您可以繼續(xù)發(fā)布采購(gòu)。也可以進(jìn)入我的后臺(tái)，查看報(bào)價(jià)

*型號(hào) *數(shù)量 廠商 批號(hào) 封裝
添加更多采購(gòu)

我的聯(lián)系方式

*
*
*