The SDM-SIO4 is a legacy product and should be purchased only as a replacement or for use with legacy dataloggers such as the CR10X. When considering the purchase of an SDM-SIO4, first consider using the SDM-SIO1 instead. Please note that the SDM-SIO4 is not compatible with all dataloggers.
Primarily for legacy dataloggers, the SDM-SIO4 adds serial I/O capacity and flexibility. It has four serial ports that communicate with serial sensors, display boards, printers, and other serial devices. After being programmed, the SDM-SIO4 communicates with connected devices in parallel with the datalogger's own program sequence.Read More
The SDM-SIO4 is a legacy product and should be purchased only as a replacement or for use with legacy dataloggers such the CR10X. When considering the purchase of an SDM-SIO4, first consider using the SDM-SIO1 instead. Please note that the SDM-SIO4 is not compatible will all dataloggers.
|Communication Rate||Speed at which data is transferred is controlled by the datalogger and can vary with the microprocessor activity as well as the length of the SDM cables.|
|Typical Transfer Rate||One byte per millisecond|
|Power Supply||Unregulated 12 V supply, 9 to 18 Vdc|
|Internal Battery||Retains configuration information only. (Lithium battery has an estimated life of 10 years.)|
|Number of Ports||4 (independently configurable for different serial data formats)|
|Serial Ports Baud Rate||25 to 115,200 bps|
|Port Configuration||9-pin D connectors|
|Data Flow Control||By datalogger or SDM-SIO4, if required, using hardware or software protocols|
|Onboard Diagnostics||Built-in system watchdog resets the processor in the event of a crash caused by transients and a built-in LED gives an indication of SDM-SIO4 status on power-up.|
|Input Voltage Limits||±25 V|
|Operating Temperature Range||-25° to +50°C|
|Weight||499 g (1.1 lb)|
|All Ports Active||40 mA|
|Quiescent||0.7 mA (quiescent state entered if there is no SDM or port activity for ~30 ms)|
Buffers (each port)
|Type||Fill & stop (Once filled, additional data received is lost.)|
|Receive (Rx)||981 bytes + 16-byte hardware buffer|
|Transmit (Tx)||981 bytes + 16-byte hardware buffer|
|Processed Data Storage||891 bytes (suitable for storing 224 4-byte Campbell Scientific floating point values)|
|Floating Point Buffer||Used only when the datalogger outputs floating point data via the SDM. This buffer is 241 bytes—sufficient for 60 floating-point values.|
Note: Future dataloggers may not support the SDM-SIO4, and therefore it is only recommended for existing networks that already contain this interface.
The SDMSIO4 Instruction controls the SDM-SIO4 operation in CRBasic. Instruction 113 controls SDM-SIO4 operation in Edlog (a Library Special PROM may be required in older dataloggers).
†Although the SDM-SIO4 is technically compatible with the CR800/CR850, CR1000, and CR3000, Campbell Scientific recommends using one or more of the SDM-SIO1 instead.
*With the CR3000 and CR5000, SDMs are connected to the ports labeled SDM-C1, SDM-C2, and SDM-C3.
Because of the minimal current drain (0.7 mA quiescent, 40 mA with all four ports active), the SDM-SIO4 is typically powered directly from the datalogger. A supplementary power supply may be required for some applications, especially where more than one SDM is operated by a single datalogger.
The SDM-SIO4 requires a desiccated, non-condensing environment; a Campbell Scientific enclosure is recommended. The SDM-SIO4's case has mounting flanges for attachment to the 1"-on-center hole grid of Campbell Scientific enclosures. Grommets and screws are provided to attach the flanges to the backplate of our enclosures.
Number of FAQs related to SDM-SIO4: 5
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The battery is a CR2032 button cell lithium battery that is user replaceable. However, after the case is opened, proper ESD (electrostatic discharge) protection is required.
Use four SDM-SIO1s or a single SDM-SIO4.
Load the string to a buffer in the SDM-SIO4, and issue the command to send the string. For details, see the SDM-SIO4 Instruction Manual.
It depends. It is possible to connect serial sensors to a datalogger without the use of an SDM-SIO4. However, if the sensors require hardware flow control or true RS-232 voltage levels, an SDM-SIO4 may be needed. The SDM-SIO1 also works with RS-485 signals and is a preferred alternative to the SDM-SIO4.
Not the same, but similar. The SDM-SIO4 provides RS-232 voltage levels; the CR1000 control ports provide 0 to 5 V only. Both usually work with all sensors, and both devices are compatible with RS-232 and TTL logic. The CR1000 is easier to set up and program for serial input. The SDM-SIO1 is a preferred alternative to the SDM-SIO4.
When compared to the CR10X, the CR1000 can handle strings as a specific data type. It also has more integrated serial interfaces including the following:
The serial I/O capabilities of the CR1000/CR3000 are similar to, and faster than, the SDM-SIO4 capabilities on a CR10X or CR23X. SDM devices are addressable and are connected to a datalogger on C1 through C3. Therefore, one benefit of using multiple SDM devices on a CR1000 datalogger is that only three control ports are used.