MD485 port pin descriptions

CS I/O Port

The CS I/O port is Campbell Scientific's input/output port. It is not a standard RS-232 pin-out. The following table provides pin-out information on the port when connected to a data logger.

CS I/O connector, 9-pin D-sub male

Pin

I/O

Function

Description

1

NC

5 V supplied by data logger

Data logger sources 5 VDC to power peripherals

2

GND

GND

GND

3

O

Ring

Raised by modem to put data logger into telecommunications mode

4

O

RX

Serial data receive line

5

I

Modem enable

Raised when data logger determines that associated modem raised the ring line

6

I

Synchronous device enable

Used by data logger to address synchronous devices; can be used as a printer enable

7

I

CLK/Handshake

Used by data logger with SDE and TX lines to transfer data to synchronous devices

8

PWR

12 V supplied by data logger

Data logger sources 12 VDC to power peripherals

9

I

TX

Serial data transmit line

I = Signal into the MD485, O = Signal out of the MD485, NC = No connection

RS-232 Port

The RS-232 port is a partial implementation of RS-232C. It is configured as Data Communications Equipment (DCE) for direct cable connection to Data Terminal Equipment (DTE) such as a computer serial port.

RS-232 connector, 9-pin D-sub female

Pin

I/O

Function

1

+5V

DCD

2

O

RXD

3

I

TXD

4

NC

DTR

5

GND

GND

6

+5V

DSR

7

NC

RTS

8

O

CTS

9

NC

RI

I = Signal into the MD485, O = Signal out of the MD485, NC = No connection

RS-485 Port

RS-485 connector, 3-pin terminal block

Pin

I/O

Function

1

GND

Signal ground

2

I/O

485_IO- (A)

3

I/O

485_IO+ (B)

I = Signal into the MD485, O = Signal out of the MD485