Milestone LD-15U User manual

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RS232C < - > RS485 CONVERTER’S MANUAL
Model: LD15U

Phone: [phone] / 97 / 98 (M) 0-98253-50221
www.interfaceproducts.info
INTRODUCTION
Milestone’s model LD-15U is a RS232 to RS 485 converter is designed for high-
speed data transmission between computer system and or peripherals over long
distance under high noise conditions. They provides dual line interface per signal.
APPLICATIONS
Application for these converters can be for factory automation, programmable logic
controllers, attendance recording systems, Barcode Readers, remote data
transmission, remote terminals, EPABX etc.
Technical Specifications
Input (RS232C) RS232C - TxD, RxD, DSR (for control), GND
Output (RS485) RS485 – Tx+, Tx-, Rx+, Rx-
Signal Protection
Each signal is protected by spike suppressor,
Opto-Isolation
Fuse protection
Selection Switch – 1 Rear side has 2 way Select switch for
Selecting 2 wire or 4 wire mode in RS422 / RS485.
Selection Switch – 2
1. Rear side has 3 way Select switch for selecting AUTO
Mode (no Handshaking Signal),
2. DSR+ Mode (+12V Control) for controlling data flow
3. DSR– Mode ( -12V Control) for controlling data flow
Maximum Distance 1.2 Kms. @ 19,200 bps
Output Cable Shielded twisted pair cable –90 Ohms/km. (Not supplied)
Transient Protection 2500 V Peak
Indication Power LED Rx LED Tx LED DSR
Power Supply 230 V, 50 Hz
Size 117 mm x 105 mm x 55mm

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INSTALLATION INSTRUCTIONS
Switch Settings
1. 2-WAY SELECT SWITCH:
Select 2-wire (half duplex) or 4-wire (full duplex) mode on 2-way switch on the
back panel.
2. 3-WAY CONTROL SWITCH: (Optional / Old Models) (In new models, it is fully automatic. No selection required)
A. Position 1 - Auto - No Handshake Control
B. Position 2 - DSR + (+12V) to enables RS485 output
C. Position 3 - DSR - (–12V) to enables RS485 output
TABLE I: RS 232 Port – D9 Female Connector
Pin No. Signal Name Input / Output
2 Tx Output
3 Rx Input
4 DSR Input
5 Signal Ground -
6,8 DTR, DTS Output
TABLE II: Output port-D9 Male connector
Pin No. Signal Name Input / Output
3 -Rx
4 +Rx
5 +Tx +Tx/+Rx
6 -Tx -Tx/-Rx
7 GND. GND.
1 Frame Ground Frame Ground

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LED Indication:
A Power Power to the unit
B TD TX Data on RS485
C RD RX Data on RS485
D DSR Transmit Control
TABLE III: RS 232 Cable
Computer End RS232 Port on LD-15U
Pin No on (D-25) Pin No on (D-9) Signal Pin No (D-9, F) Signal
2 3 Tx 2 Tx
3 2 Rx 3 Rx
6 6 DSR 6 DTR
7 5 GND 5 Sig. Gnd
20 4 DTR 4 DSR
4,5 7,8 RTS.CTS 8 RTS
The above connections are for Standard PC COM Port. Please verify these
connections for any other system or terminal before making the cable.
LONG DISTANCE CABLE LAYING
Long distance cable between two RS422/RS485 interfaces must be a twisted pair
shielded cable. The pair should be used for each signal type + and – signal. This
gives high common mode noise rejection. While laying the cable, care should be
taken not to lay this cable parallel to power line cables. The cable resistance should
not be more than 90 ohms/1000 meters. The cable should be run through conduit
pipe for physical protection.

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Cable Diagram for RS-422 / 485:
TABLE IV: OUTPUT CABLE – 4 Wire (RS-422)
D9-Male (LD-15U) Pin No. Instrument
-Rx 3 -TX
+RX 4 +TX
+TX 5 +RX
-TX 6 -RX
TABLE V: OUTPUT CABLE – 2 Wire (RS-485)
D9-Male (LD-15U) Pin No Instrument
+TX / + RX 5 +TX / +RX
-TX / - RX 6 -TX / -RX
 Above Cable diagram is for, from unit to (ML LD 15 U) to P.L.C.
 DB-9 Male is on ML LD 15U. So, you need to use DB-9 Female at RS-422 /
485 LD 15U side.

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Testing Manual for
RS-232 to RS-422/RS-485 Converter
(ML LD-15 U
For testing RS-232 to RS-485 Converter, one should follow the following
steps:
1. Check the physical condition of the unit.
2. Plug-in the Converter in the power socket to check the power on the
unit.
3. Attach the input cable, which co es with the Converter to get the
input of RS-232 signal fro the co puter.
4. Prepare the Loop-back dongle and attach it on the output (RS-
422/485) Port. To prepare this dongle, you need to short pin no. “3 & 6”
and “4 & 5” of a 9 pin Fe ale connector at the soldering side. Connect
it on the Output port Do not connect any other pin.
5. Start the Hyper Ter inal Software for testing the converter. Go to “Start
-> Programs -> Accessories -> Communications -> Hyper Terminal”.

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6. Give the proper file na e when asked at the start up. (See i age 1.01)
(Image 1.01
7. Provide proper COM Port when asked to. (See i age 1.02)
(Image 1.02

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8. Set the properties of the COM Port as shown in the i age 1.03
(Image 1.03
9. Go to File Menu + Properties. Go to Setting Tab in the Properties
window. (See i age 1.04)
(Image 1.04

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10. In the Settings Tab Click on “ASCII Setup…”. In the ‘ASCII Sending’ part,
check the box of the line “Echo typed characters locally”. Then Click
OK. Again click OK for Properties window. (See i age 1.05)
(Image 1.05

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11. Set the converter to ‘4 wire’ by a slide switch, situated on the rear
panel of the converter. Now, if you type anything it will give display
typed twice. (See i age 1.06)
(Image 1.06
If you can see the ter inal window as per i age 1.06 successfully, it eans
that the converter is working properly.