IC485+I Users Manual Part Number 1103 Sealevel Systems, Inc. PO Box 830 Liberty, SC 29657 USA Telephone: 864.843.4343 Fax: 864.843.3067 www.sealevel.
Contents INTRODUCTION .....................................................................................................................................................1 OVERVIEW................................................................................................................................................................1 WHAT’S INCLUDED...................................................................................................................................................
Introduction Introduction Overview The Sealevel Systems IC485+I is an isolated single channel RS-232 to RS-422/485 asynchronous converter. It provides one field selectable RS-422/485 serial port supporting asynchronous data rates up to 115.2K bps. The IC485+I is self-powered allowing it to correctly drive multi-drop RS-485 networks. Isolation is important in installations where the equipment being connected to the PC is either far from the PC, or on a different power transformer circuit.
Card Setup Card Setup RS-485 Enable Modes RS-485 is ideal for multi-drop or network environments. RS-485 requires a tri-state driver that will allow the electrical presence of the driver to be removed from the line. The driver is in a tri-state or high impedance condition when this occurs. Only one driver may be active at a time and the other driver(s) must be tri-stated. The output modem control signal Request To Send (RTS) is typically used to control the state of the driver.
Card Setup Communication Mode Examples (Dip switch SW1) OFF ON 1 2 Figure 1- Dip switch SW1, RS-422 OFF ON 1 2 Figure 2 – Dip switch SW1, RS-485 ‘Auto’ Enable OFF ON 1 2 Figure 3 – Dip switch SW1, RS-485 ‘RTS’ Enable OFF ON 1 2 Figure 4 – Dip switch SW1, RS-485 ‘Data’ Enable Sealevel Systems IC485+I Page 3
Card Setup Line Termination and Receiver Echo Off/On Typically, each end of the RS-485 bus must have a line-terminating resistor (RS-422 terminates at the receive end only). A 120-ohm resistor is across each RS-422/485 input in addition to a 1K-ohm pull-up/pull-down combination that biases the receiver inputs. DIP-switch SW2 allows customization of this interface to specific requirements. Each DIP-switch position corresponds to a specific portion of the interface.
Card Setup Electrical Interface Examples (DIP switch SW2) OFF ON 1 2 3 4 5 6 Figure 6 – RS-422 with Termination and Receiver Echo OFF ON 1 2 3 4 5 6 Figure 7 – RS-485 2-wire with Termination and Receiver No Echo OFF ON 1 2 3 4 5 6 Figure 8 – RS-485 2-wire no Termination and Receiver No Echo Sealevel Systems IC485+I Page 5
Installation Operating System Installation (For Windows Users) RS-422/RS-485 Four Wire Master/RS-485 Two Wire Auto Mode Installation If your application is 4-wire Full Duplex RS-422 or 4-Wire RS-485 Master, where control of the transmitter is not required, or 2-wire RS-485 and you intend to use the Auto Mode to control the transmitter, simply connect the IC485+I to an existing RS-232 COM: port. This will utilize the Operating System Serial Driver to control the COM: port.
Installation The last method is ‘Data Enable’ which uses the transmitted data stream to enable the transmitter and requires no special software drivers. When the transmitted data is a low (0), the transmitter will be enabled to drive the line. When the transmitted data is a high (1), the transmitter will be tri-stated relying on the line biasing resistors to pull the line to the proper state. Due to this, termination must not be used and thus data rate and cable length are reduced accordingly.
Installation Other Operating Systems Linux includes a full-featured serial driver that includes support not found in Microsoft’s serial driver. Most serial drivers offer a mechanism to control RTS from the application layer. While this is not as efficient and normally means using ‘Echo’ to know when to turn off the transmitter, for most applications this is adequate. The ‘Auto Enable’ and ‘Data Enable’ modes can also be used. Refer to your operating system documentation for specifics.
Technical Description Technical Description The Sealevel Systems IC485+I converts an existing RS-232 serial port into an isolated, field selectable, RS-422/485 port for industrial automation and control applications. Isolation is important in installations where the equipment being connected to the PC is either far from the PC, or on a different power transformer circuit.
Specifications Specifications Environmental Specifications Specification Temperature Range Humidity Range Operating 0º to 70º C (32º to 158º F) 10 to 90% R.H. Non-Condensing Storage -50º to 105º C (-58º to 221º F) 10 to 90% R.H. Non-Condensing Manufacturing All Sealevel Systems Printed Circuit boards are built to UL 94V0 rating and are 100% electrically tested. These printed circuit boards are solder mask over bare copper or solder mask over tin nickel.
Appendix A - Troubleshooting Appendix A - Troubleshooting Serial Utility test software is supplied with the Sealevel Systems adapter and should be used in the troubleshooting procedures. Using this software and following these simple steps, most common problems can be eliminated without the need to call Technical Support. 1. The IC485+I is a level converter and therefore requires no system resources such as I/O ports or IRQs. The I/O resources of the host RS-232 COM: port will be used to access the port.
Appendix B - How To Get Assistance Appendix B - How To Get Assistance Please refer to Troubleshooting Guide prior to calling Technical Support. 1. Begin by reading through the Trouble Shooting Guide in Appendix A. If assistance is still needed please see below. 2. When calling for technical assistance, please have your user manual and current adapter settings. If possible, please have the adapter installed in a computer ready to run diagnostics. 3.
Appendix C – Electrical Interface Appendix C - Electrical Interface RS-232 Quite possibly the most widely used communication standard is RS-232. This implementation has been defined and revised several times and is often referred to as RS-232 or EIA/TIA-232. The IBM PC computer defined the RS-232 port on a 9 pin D sub connector and subsequently the EIA/TIA approved this implementation as the EIA/TIA-574 standard.
Appendix D - Asynchronous Communications Appendix D - Asynchronous Communications Serial data communications implies that individual bits of a character are transmitted consecutively to a receiver that assembles the bits back into a character. Data rate, error checking, handshaking, and character framing (start/stop bits) are pre-defined and must correspond at both the transmitting and receiving ends.
Appendix E - Ground Loop Phenomenon Appendix E - Ground Loop Phenomenon What is Ground Loop? Ground loop Phenomenon occurs when two (or more) pieces of equipment are connected together with a common ground and a different ground potential exists at each location. This current can cause the connected equipment to experience noise that in turn causes data transmission errors. In the extreme this ground current can cause equipment malfunction or even destruction.
Appendix F - Silk-Screen Appendix F - Silk-Screen 2.688 in 2.
Appendix G - Compliance Notices Appendix G - Compliance Notices Federal Communications Commission Statement FCC - This equipment has been tested and found to comply with the limits for Class A digital device, pursuant to Part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment.
Warranty Warranty Sealevel's commitment to providing the best I/O solutions is reflected in the Lifetime Warranty that is standard on all Sealevel manufactured products. We are able to offer this warranty due to our control of manufacturing quality and the historically high reliability of our products in the field. Sealevel products are designed and manufactured at its Liberty, South Carolina facility, allowing direct control over product development, production, burn-in and testing. Sealevel Systems, Inc.
