• Fast auto TX-enable RS232 to RS485 interface converter for 2-wire, half-duplex communications, at distances up to 4000 ft. and data rates up to 115.2Kbps (with short data strings).
• Recommended for special applications only where power is not available.
• Choose from two different models.
GENERAL DESCRIPTION and TYPICAL APPLICATIONS:
The LP24 is a fast Async bi-directional RS232 to RS485 interface converter for 2-wire, half-duplex applications, with an automatic TX enable circuit, that will operate at data rates up to 115.2Kbps (with short data strings). The unit has jumpers for RS232 DTE/DCE selection, and fixed/automatic data rate selection. The Model LP24W has a spring-loaded Wago terminal strip that will accommodate 20-28AWG wire on the RS485 side of the interface. The Model LP24R provides an RJ11/12 connector for RS485 connections.
The LP24 is designed for office and/or indoor applications (non-isolated). Can be used for point to point, or multi-drop 2-wire systems.
Special notes: Even though our unique port-powered deign is very power efficient, we do NOT generally recommend port powered devices, because of potential problems with the limited power available from a typical RS232 port. Just the characteristic impedance of the cable can load down the transmitted signals to a remote device. If strings are limited to short bursts (depending on baud rate) extended distances can be achieved. Long string cause the onboard capacitance to discharge into the load/line and the signal strength degrades with time. In many applications over short distances (up to about 50 ft.) good operation can be expected. It is generally not possible to add termination in port powered applications. Light on-board bias resistors are provided (22K).
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LP24.pdf | Converter schematic |
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PHYSICAL PROPERTIES and FEATURES:
| RS232 | 3-wire interface to RJ11/12 Connector (TX, RX, Common). |
| RS485 | Optional 3-position Wago terminal strip or RJ11/12 connector. |
| Power | RS232 Port powered only (RTS, DTR) high state +7V |
| LEDs | None (See ASC24W, ASC24R, and ASC24T powered units) |
| Bias | 22K Ohm pull-up and pull-down (fixed) |
| Termination | None |
| Special | Automatic or fixed data rates of 9600,N,8,1 or 19200,N,8,1 |
| Protection | None (See ASC24W, ASC24R, and ASC24T powered units) |
SPECIFICATIONS:
| Distance | RS485 up to 4000 ft. (1250 meters) |
| Operation | 2-wire half-duplex RS485 |
| Format | Asynchronous data with any combination of bits, parity, stop (auto mode) |
| Speed | Up to 115.2Kbps |
| Temperature | 0-65C (32-150F) ambient |
| Humidity | 10-90% non-condensing |
| Voltage | +7V minimum on RTS and/or DTR |
| Power | Under 1/8 Watt (typical) + external load |
| Size | 2.50" X 2.00" X 0.9" (PC Board), with connectors: 2.50" X 2.15" |
| Mounting | 4-Holes 2.00" X 1.50" (built-in standoffs for #6 hardware) |
OPTIONS AND ORDERING INFORMATION:
| LP24W | $39.00 ea. (Circuit board only, with Wago terminals) |
| LP24R | $39.00 ea. (Circuit board only, with RJ11/12 connector) |
| Enclosure | $8.00 ea. (Small) |
| Cable | $7.50 ea. (RS232, 7 ft., specify DB9F-7 or DB25F-7) |
| Supply | N/A |
| *LP24W with all options (DB9F cable): LP24W-B9F @ $54.50 ea. (Qty. 1-9) |
| *LP24R with all options (DB9F cable): LP24R-B9F @ $54.50 ea. (Qty. 1-9) |
Please call us at: 513-874-4796
 Contact Information:R.E. Smith 10330 Chester Rd., Cincinnati, Ohio 45215 Phone: 513-874-4796 Fax: 513-874-1236 |