- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄358777 > LDM485-PE (Electronic Theatre Controls, Inc.) 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors PDF資料下載
參數(shù)資料
| 型號(hào)： | LDM485-PE |
| 廠商： | Electronic Theatre Controls, Inc. |
| 元件分類： | RS-232 |
| 英文描述： | 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors |
| 中文描述： | 5V的高速RS - 232收發(fā)器與0.1uF電容 |
| 文件頁(yè)數(shù)： | 3/4頁(yè) |
| 文件大?。?/td> | 179K |
| 代理商： | LDM485-PE |
24
2400 baud and above by a proportionate amount. For example, shielded
cable wth 50pF/ft (164pF/m) would reduce the distances by 50%.
Recommended wre gauges are #18 to #24 (0.82-0.20mm
2
).
For baud rates of 1200 and below distances are limted by DC voltage
drop. For 2400 baud and above, distances are limted by pulse
distortion. The use of low-capacitance cable can extend the distances
shown. Belden 9182 and 9184 are, respectively, single and dual
twsted-pair cables that are especially designed for high-speed data
communications applications. With these cables the distances can
be extended by 50%. However, the DC-resistance-limted distance
given under 1200 baud may not be exceeded.
Cable capacitance for individually shielded wre pairs is usually given
by manufacturers as capacitance between wres and capacitance from
each wire to the shield. The effective transmssion line capacitance
is approximately the interwire capacitance plus one-half of the wire-
to-shield capacitance.
Installation
Installation of the LDM485 consists of attaching it to its mating 25-pin
connector on the termnal of the host computer either directly or through
a cable. Optional mounting screws and screwjacks are provided.
The DCE/DTE (data-communication equipment/data terminal
equipment) swtch must be set to be complementary to the termnal
or computer port (DCE connects to DTE and DTE to DCE). Since the
LDM485 is a communications device, its normal setting is DCE.
In the event that the host port is not known, the LED indicators may
be used to find the proper swtch setting. The transmt and receive
LEDs wll be off during a MARK, which is the normal, or standby,
condition when no data is being transmtted. Set the swtch to the
position which allows these LEDs to be off. The field wring as shown
in Figure 2 must be correct. It is sometimes useful to tie the RS-485
data output back to the RS-485 input during initial check-out.
The four other LEDs indicate the status of various control conditions and
wll be on when these functions are asserted. An open circuit to Request
To Send wll be interpreted as assertion, allowng convenient operation
wth equipment not supporting this function. An open circuit on the
Receive Data line of the RS-485 circuits wll be interpreted as a MARK.
For 2-wre half-duplex and for 2-wre multi-drop installations, echo
suppression is available by strapping P1 pin 16 to P1 pin 17. Then RTS
asserted enables echo suppression and forces RD (P1 pin 3) to a MARK.
Data Termnal Ready, DTR, must be asserted before the LDM485 can
transmt data. This is normally done by the host computer. For
situations where the host equipment does not have the capability of
supplying a DTR signal, RLSD may be used to automatically assert
DTR. On the RS-232 connector P1 of each LDM485, simply connect
RLSD pin 8 to DTR pin 20. This connection is not appropriate for
multi-drop installations.
Figure 2. Field Wiring, LDM to LDM
Unit 1
Unit 2
Function
Function
Terminal
Terminal
12VAC
PWR RTN
(local)
A
B
A’
B’
A
B
A’
B’
RTS
Output
CTS
Input
TD
Output
RD
Input
SIGNAL RTN
SIGNAL RTN
12VAC
PWR RTN
(local)
A’
B’
A
B
A’
B’
A
B
SIGNAL RTN
SIGNAL RTN
1
2
3
4
5
6
7
8
10
11
9
12
1
2
3
4
5
6
1
2
5
6
3
4
10
11
7
8
9
12
7
8
9
10
11
12
Note: Signal return
not required. Shield
connection if used.
Notes: (1) For data channels MARK is A negative relative to B. (2) For control lines Assertion is A
positive relative to B. (3) RTS = Request To Send, CTS = Clear To Send, TD = TransmttedData, RD
= Received Data. (4) Recommended wre sizes are 14AWG to 22AWG. Belden 8442 or Signal 1172
are typical low cost, nonshielded, twisted pair cables for use with LDM485. (5) Signal return is not
required. Cable shield, if used, should be connected to SIGNAL RTN. (6) LDM485 units are suitable for
use in RS-422/485 applications.
For multi-drop installations, the followng points should be considered
(see Figure 3 for multi-drop wring connections):
1. If the LDM485 is not powered, it releases the transmt bus so
other RS-485 devices may use the bus.
2. Local equipment connected to the RS-232 connector must not
leave DTR in the asserted state.
3. An open circuit or zero volts on the RS-232 connector pin 20
(DTR) is equivalent to disassertion.
4. The RS-485 line should be termnated at both ends using internal
line termnation DIP swtches (see Figure 3). Stub length off the main
line should be as short as possible.
5. DTR should be asserted at least 5.0μs before start bit and
disasserted at end of last stop bit. This disables the RS-485 line after
6.0μs mn.
WARNING!
Because PWR RTNand RS-232 GND (P1-7) and Shield (P1-
1) are common, when powering more than one unit fromthe same
transformer wre all units' 12VAC's together to one side of the secondary
and all PWR RTNs together to the other side of the secondary
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LDM485-PT | 5V High-Speed RS-232 Transceivers with 0.1uF Capacitors |
| LDQ-M282RI | 0.28 inch FOUR DIGT, SEVEN SEGMENT DISPLAY, GREEN, GRAY FACE WITH MILKY WHITE DIFFUSED SEGMENTS |
| LDQ-M512RI | LDQ-M512RI |
| LDQ-M514RI | LDQ-M514RI |
| LDQ2G181MERA | ALUMINUM ELECTROLYTIC CAPACITORS |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LDM485-PT | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Fully Isolated Limited Distance Modem, RS-232/485 Converter |
| LDM485-S | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Fully Isolated Limited Distance Modem, RS-232/485 Converter |
| LDM485-SE | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Fully Isolated Limited Distance Modem, RS-232/485 Converter |
| LDM485-ST | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Fully Isolated Limited Distance Modem, RS-232/485 Converter |
| LDM60 | 制造商:General Tools 功能描述:LDM60 Laser Distance Meter 制造商:General Tools 功能描述:LASER DISTANCE METER |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。