Impulse 1105 - Manual (Page 11)

Technical Description
Sealevel Systems DIN485+I Page 9
Technical Description
The Sealevel Systems DIN485+I converts an existing RS-232 serial port into an isolated, DIN rail mountable, 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.
Ground loop current is a commonly neglected and misunderstood phenomenon that leads to data loss and the
destruction of communications interfaces.
Connector Pin Assignments
Power/RS-232 Pin Assignments (6 Position Screw Terminal)
Signal Name Pin # Mode
TD Transmit Data 1 Input
RD Receive Data 2 Output
RT Request to Send 3 Input
+V +DC Supply Input 4 Input
-DC Supply Input 5 Input
Shield 6 Input
Technical Note: The modem control signals are biased in the following fashion when using Sealevel’s CA-186
cable: RTS and CTS are connected, DTR is connected to DCD and DSR, and RI is tied inactive.
RS-422/485 Pin Assignments (6 Position Screw Terminal)
Signal Name Pin # Mode
RDB R+ Receive Data Positive 7 Input
RDA R- Receive Data Negative 8 Input
TDB T+ Transmit Data Positive 9 Output
TDA T- Transmit Data Negative 10 Output
GND Ground 11
SHIELD Shield 12