Campbell Scientific recently replaced the SDM-SIO1 with the SDM-SIO1A I/O Expansion Module. Improvements over the SDM-SIO1 include a smaller size, lower cost, and a larger data input buffer. Like its predecessor, the SDM-SIO1A adds an RS-232, RS-422, or RS-485 (half- or full-duplex) serial port to an SDM-capable datalogger for interfacing an intelligent sensor, actuator, or display. The serial port interface is transient and surge protected, eliminating the need for separate transient protection in most applications. Up to 15 SDM-SIO1A modules can be connected to a single datalogger SDM port.
Campbell Scientific is also adding the SDM-SIO4A Four-Channel I/O Expansion Module to our product line. Although it has a similar name, the SDM-SIO4A is not a direct replacement for the SDM-SIO4, which is mostly used with retired dataloggers. The new SDM-SIO4A consists of four SDM-SIO1A modules contained in a single package. It adds four individually configurable and addressable RS-232, RS-422, or RS-485 (half- or full-duplex) serial ports. Each serial port interface is transient and surge protected. Up to three SDM-SIO4A modules can be connected to a single datalogger SDM port. The SDM-SIO4A will be available soon.