Universal Serial Interface Controller Set
SM131-132

SM131 Ten x 10 AMP Output Relays	SM132 20 x Inputs or 20 x Outputs

General Description
The SM131, SM132 card set has been produced as a generic method of controlling or monitoring a large number of devices via a single conventional RS232 PC interface. A 10 way ribbon cable bus between modules allow many modules to share a common PC interface. Any combination of inputs and outputs (in blocks of 10) may be connected to the common serial bus, totalling up to 160 ports.

The SM131 has ten 10 Amp relays on board for switching 10 outputs to a common AC or DC rail.
The SM132-O has twenty independent ‘Open Collector’ outputs for the control of external relays & devices
The SM132-I has twenty independent 8-bit inputs for monitoring analog or digital devices (sensors or switches)

After a simple null-modem DB9 cable is attached from a PC to any of the boards, then all of the ports on all modules are accessible by a simple command set at 1200 baud that may be generated by a dumb terminal or a customised windows based application. A simple Visual Basic demonstration program is available to show how a large number of devices may be monitored or controlled from within a ‘Windows’ PC environment.

Features

• Each Module May Operate From Its Own 240v Supply, Or An External 12v Dc
  (where multiple modules are used, only one needs to be connected to a power source)
  
• Modules May Be Stacked For Compact Installation
  (L:178 W:101 H: 42mm)
  
• All Output Port Conditions Are Stored In Non-Volatile Memory
  ( In the event of power interruption, previous output states are remembered at power up)
  
• On-Board Led Indicators Show The Present State Of All Outputs
  
• Modules May Be Connected Direct To A Pc, Or Via Modem
  ( As the data transmission speeds are low, this may even happen via cell-phone modem)

The command language resembles the Hayes ‘AT’ modem command set. For example, sending the text string ‘AE03+’ would access a 10 port group strapped to address ‘0’, then activate output ‘3’ Sending ‘AE03-‘ would turn it off. All successful commands trigger an ‘OK’ confirmation

Other commands may reset an entire 10 port output group, check the present state of an output group or perform a simple ‘Echo’ test to prove that communications to a particular module are open.

Inputs in any 10 port group are checked by sending a AEnIP command (where ‘n’ is a 0 to F card address) A reply such as AEn0001001001OK will indicate which switched inputs are on or off. If the DIG-ON jumper is removed in a 10 port block, the reply will contain an 8bit (0-255) decimal value to represent the analogue value on each channel. Every input has a switchable ‘10K pullup’ resistor available to tie un-terminated inputs to ‘logic 1’.

SM131 / SM132 Supported Commands

• Terminal protocol is 1200 baud, N,8,1 Characters are not echo’ed back to the host, so the user must turn on ‘Local Echo’ on their terminal to view any characters sent.
  
• All commands must be in UPPER CASE. Backspace characters are not supported.
  
• Letter ‘n’ in the table below represents one of sixteen card addresses (0-9,ABCDEF) as selected by the four ‘Card Identity’ jumpers for each group of 10 inputs or outputs.