Impulse 1105 - Manual (Page 10)

Installation
Sealevel Systems DIN485+I Page 8
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.
Physical Installation
The DIN485+I can be connected to any existing RS-232 port. A cable such as Sealevel’s’ CA-186 can be used to
attach the DIN485+I DB-25F to the PC’s DB-9M connector.
1. Locate an existing RS-232 COM: port and connect the DIN485+I.
2. With
the DIN485+I case open, configure DIP-switches SW1 and SW2 for your application.
3. Connect the wiring to your external device via the provided 6-position screw terminal. The signals are labeled
on the board’s silkscreen. From the included hardware, select the strain relief clamp that best fits your cable.
4. Make sure all connections are secure and that strain relief is correctly installed.
5. Close
the DIN485+I case and connect the included AC adaptor.
6. If the DIN485+I is in RS-422 mode, the EN led should now be on since the transmitter is always enabled.
Installation is complete.
Please Note:
On power-up, the DIN485+I scans the Mode Select DIP-switch (SW1) one time to determine the communication
mode and then branches to the selected control logic. No attempt is made to periodically check the switch for a mode
change. This is done for two reasons. First, our experience shows that a device such as this is configured for the
required application and the mode is not changed after this. Due to this reason, the product is not burdened with the
overhead of always checking this switch. At higher baud rates this becomes especially critical due to the speed of the
onboard microcontroller. The utmost priority is given to sampling the incoming data.
Why is this important? If the DIN485+I has been configured for a particular mode, and for some reason it has
become necessary to change the communication mode, remove power, reconfigure the Mode Select DIP-switch
(SW1) for the new mode, and reapply power.