Applied Digital SECU-16I — Input Expansion Module Manual

Manual for the Applied Digital SECU-16I™ input expansion module — adds 16 supervised or analog inputs to an ADICON™ control system.

Overview

The SECU-16I™ module allows 16 inputs to be added to an ADICON™ control system. Inputs may be supervised (switch closure) or analog.

Specifications

Setup

1. Remove the SECU-16I™ top cover.
2. Connect the power supply to the two screw terminals labeled POWER.
3. Connect the COM A and COM B terminals to the ADICON™ bus.

Two types of inputs may be used: supervised (a passive, non-current-supplying input such as a relay or switch) and analog (a varying voltage input such as a light sensor). Input types are controlled in groups of eight via jumpers JP1 and JP2:

To use an input as a supervised input, a 1K Ohm resistor (supplied) must be placed across the input.

Operation — ADICON™ LED Codes

• ACTIVE LED — Slow Blink: Module has a valid address.
• ACTIVE LED — Rapid Blink: Auto Address mode active.
• COMMS LED: Blinks rapidly during ADICON™ communications.

SECU-16I™ Parameters

Inputs are represented by I/O points within a module — the SECU-16I™ has 16 I/O points; input 1 = I/O point #0, input 2 = I/O point #1, and so on.

Supervised Inputs

A supervised input is a contact closure input such as a switch or relay. The SECU-16I™ reports OFF when the switch is open and ON when the switch is closed.

Analog Inputs

Analog inputs vary from 0–5VDC (e.g., a light sensor). The SECU-16I™ compares the reading to the low and high threshold parameters:

• If the analog value is between the low and high thresholds, the input reports OFF.
• If the value is below the low threshold or above the high threshold, the input reports ON.

Setting Threshold Values

Threshold and analog values are determined using:

• Analog Reading = Sensor Voltage × (256 / 5) = Sensor Voltage × 51.2
  Example: a 2V light sensor reading = 2 × 51.2 = 102
• Voltage = Analog Reading × (5 / 256) = Analog Reading × 0.01953
  Example: a high threshold of 192 = 192 × 0.01953 = 3.75V

Threshold values are stored in parameters 2 and 3, set via the C-Max™ module parameter utility.

Reverse Logic

Threshold values can also implement reverse logic — for example, to make a door sensor report OFF when closed and ON when open, set the low threshold to 0 and the high threshold to 128. For OFF when open / ON when closed, set the low threshold to 128 and the high threshold to 255. This works with either analog or supervised inputs.

Example: Light Sensor for Outdoor Lighting

Determine the threshold voltages for when the lights should turn on and off. In this example: 1.5V (analog reading 77) turns the lights on, and 3.5V (analog reading 179) turns the lights off. The lower the light on the sensor, the higher the analog reading — the controller logic turns lights off after sunrise (once light exceeds the threshold) and on after dusk (once light falls below the threshold).