Digital Peripherals / SDM-SIO1A
SDM-SIO1A 1-Channel Serial I/O Module
Serial I/O Expansion for Dataloggers
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Overview

The SDM-SIO1A is a serial I/O expansion module for Campbell Scientific dataloggers. It is designed to add an additional RS-232, RS-422, or RS-485 (half- or full-duplex) serial port to an SDM-capable datalogger for the purposes of interfacing with an intelligent sensor, actuator, or display. Up to 15 SDM-SIO1A modules can be connected to a single datalogger SDM port. The SDM-SIO1A behaves much like a native datalogger serial port and uses the same familiar serial I/O commands. The SDM-SIO1A is transient and surge protected to IEC61000-4-5 level 4 on the serial port interface, avoiding the need for separate transient protection in most applications.

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Benefits and Features

  • Easy and compact method to add up to 15 additional serial ports to an SDM-capable Campbell Scientific datalogger
  • Fully compliant with the RS-232, RS-422, and RS-485 (half- and full-duplex) standards
  • Can buffer large amounts of serial sensor data between datalogger processing events
  • Supports datalogger terminal "talk-through" mode, facilitating serial device testing and diagnostics
  • Includes transient and surge protection on the serial port interface, eliminating the need for separate transient protection
  • Low idle power consumption, which is ideal for battery-powered stations

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Detailed Description

The SDM-SIO1A connects to a remote serial device using industry-standard hardware that can be set to true RS-232, RS-485, or RS-422 signal levels. When operating in RS-232 mode, the module also supports hardware handshaking. RS-422 mode is functionally the same as RS-485 mode, except the connection is limited to a point-to-point system. Connections and programming for RS-422 are otherwise identical to RS-485.

The SDM-SIO1A will accept serial data up to 6143 bytes and store it in its buffer. This allows remote equipment to transmit large amounts of data without needing to stop other processes in the datalogger.

Up to 15 SDM-SIO1A modules can be connected to a single datalogger using the SDM port, allowing a user to connect 15 different serial devices to a datalogger with ease. This is in addition to any connections made to the dataloggers via other serial ports.

The SDM Jumper Wire Kit (pn 32505) connects up to four SDMs to the datalogger. This kit is recommended when multiple SDMs are connected to one datalogger or for extremely short distances between the SDM and datalogger. The CABLE5CBL-L cable is recommended for connecting a single SDM to the datalogger, and for longer distances between the SDM and datalogger.

Specifications

Supported Data Rates 300, 1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115200 bits/s
Supported Modes of Operation
  • Hardware CTS/RTS flow control is supported in RS-232 mode. The handshaking lines can also be used as general purpose I/O lines.
  • RS-232 (full duplex and receive only)
  • RS-485 (half and full duplex)
  • RS-422 (half and full duplex)
Supported Data Format
  • In 7-bit mode with no parity, the user must ensure that the characters received by the SDM-SIO1A have a delay of at least one bit period or greater between them. This does not affect any other configuration and does not affect transmissions out of the SDM-SIO1A.
  • 8, 7 bit data size; none, odd, or even parity; one or two stops bits
Auto Baud Rate Detection Not supported
PakBus Communications Use of the serial port for general PakBus communications is not currently supported.
Voltage
  • Power supply +12 V connection
  • 7 V (minimum)
  • 12 V (nominal)
  • 30 V (maximum)
Temperature Range -40°C to +70°C (standard)
Standard Humidity Range 0 to 95% (non-condensing)
EMC Compliance The SDM-SIO1A has been tested and shown to comply with IEC 61326. The device incorporates transient and surge protection that is designed to meet IEC61000-4-5, level 4, providing the device is adequately grounded.
Mounting Clips Optional DIN rail mounting clips are available, which can be fitted to the base of the case.
Mounting Holes Two spaced 7.6 cm (3 in.) apart
Dimensions 6.4 x 6.25 x 2.2 cm (2.51 x 2.46 x 0.86 in.) excluding mounting tabs

Buffer Sizes

-NOTE- Both transmit and receive buffers are fill and discard type. That is, after the buffers become full, no new information is accepted and all further data is discarded until space is made when the datalogger requests data from the SDM-SIO1A.
Transmit Buffer Size 767 bytes (buffer from the datalogger to the sensor)
Receive Buffer Size 6143 bytes (buffer from the sensor to the datalogger)

Current Consumption

Standby Current
  • 110 µA (nominal)
  • 150µA (max)
Active Current 9.6 to 11.7 mA (depending on transmit mode and connections made)

Compatibility

Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.

Data Loggers

Product Compatible Note
CR1000
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR295X (retired)
CR3000 On the CR3000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3.
CR5000 (retired) The CR5000 is compatible with the SDM-SIO1A, but the operating system must be OS 6 or higher. On the CR5000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3.
CR6
CR800
CR850
CR9000X The CR9000X's operating system must be OS 6 or higher.

Mounting Equipment

Product Compatible Note
ENC10/12
ENC10/12R
ENC12/14
ENC14/16
ENC16/18

Additional Compatibility Information

Datalogger Considerations

The SDM-SIO1A does NOT support auto baud rate detection nor the use of the serial port for general PakBus communications.

Enclosure Considerations

The SDM-SIO1A requires a desiccated, non-condensing environment; a Campbell Scientific enclosure is recommended. The SDM-SIO1A has built-in keyhole flanges for mounting to the backplates of Campbell Scientific enclosures.


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