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SDAM 8 Channel Analog Input Smart Card

This product has been discontinued. This web page is provided so current customers using the product can have a quick reference for specifications. Please contact Automation Electronics for current products that may meet your needs.

8 channel A/D smart card8 Channel Analog Input Smart Card

The Automation and Electronics, Inc. SDAM was designed to provide analog input expansion capability for Programmable Logic Controllers (PLCs). With a low power requirement and a wide operating temperature range, the SDAM is ideal for use in remote 120 VAC, 24 VDC, or solar powered distributed I/O systems. It can also be used as a stand-alone MODBUS analog input module.

The SDAM is a microprocessor based 8 channel analog input board. The inputs can be used in either voltage or current sensing mode. Jumpers are used to configure each of the inputs. Connections are provided for end devices that provide their own loop power and also to provide the loop power to the end devices.

The analog inputs are digitized using a 12-bit analog to digital converter and put through a digital filter. The on-board option switches can be used to select the digital data filtering applied. The on-board microprocessor then makes these readings available to either host systems or master controllers via a serial data highway.

The data highway is implemented using the built in RS-485 serial port. All of the Smart Card series can be daisy chained together using these serial ports. Each Smart Card responds to MODBUS polls or commands from a master. An on-board address selector switch allows each board to be easily configured for any MODBUS address. This RS-485 data highway can then be used to create a scalable, flexible input / output expansion array.


  • Analog input value backup (24 hour via on-board capacitor)
  • MODBUS RTU protocol
  • On-board address switch (0-255)
  • Four on-board option switches
  • Two RJ45 jacks for RS-485 serial data
  • Selectable RS-485 termination
  • Expansion connector for our P-type piggyback modules


Size: 4-1/2" x 9" PC board
Mounting: Snap track
Operating temperature: -40 to +158 deg. F (-40 to +70 deg. C)
Relative humidity: 5 to 90% non-condensing
Power requirements
Typical: Processor - Less than 100 mA @ 10 to 30 VDC
CPU / Memory
CPU: 68HC11
Memory: 128 kB flash, 32 kB EEPROM, 2 kB RAM
Input configuration
Standard: Eight analog inputs; 0-5 VDC or 0-20 mA selectable, 12-bit conversion, 130 mS. sampling interval, +/- 1.0 LSB linearity
RS-485: 9,600 baud; two RJ45 connectors
Protocols: MODBUS RTU protocol