User manual

5
Manual WM-IIRO-8
Chapter 1: Introduction
Features
• RS232 Serial Interface to Host Computer.
• 900 MHz Wireless Connection Between Host Computer Modem and W M-IIRO-8.
• 8 Optically-Isolated, Non-Polarized Digital Inputs with Change of State(COS) Detection.
• 8 SPDT Electro-Mechanical Relay Outputs that Switch Up to 1 Amp Each.
• Digital Outputs May Be Either Level or Pulsed.
• Type 8031 Microcontroller w ith 8K RAM and 8K EEPROM. (32K X 8 optional)
• Ability to Program with Custom Firmware over Wireless Connection
• NEMA4 Enclosure for Harsh Atmospheric or Marine Environments.
Functional Description
The WM-IIRO-8 is an intelligent 8-bit parallel digital I/O unit that communicates with ACCES’s
Wireless Serial Modem via a 900 MHz wireless connection. The W ireless Serial Modem connects
to a host com puter’s standard COM port using an RS232 (or RS485) serial communications protocol.
Both the W M-IIRO-8 and the W ireless Serial Modem are packaged in NEMA4 enclosures for remote
installation in harsh environments. ASCII-based comm and/response protocol permits communication
with virtually any computer system. It can operate at baud rates up to 9600 baud at distances up to
7 miles line-of-sight.
The 8 isolated inputs can be driven by either AC or DC signals and are not polarity sensitive.
Input signals are rectified by photocoupler diodes. Standard 12/24 AC control transformer
outputs can be accepted as well as DC voltages. The input voltage range is 3 to 28 volts (rms).
Unused power dissipates through a 1.8KS resistor. External resistors connected in series with
this may be used to extend the input voltage range. Each input circuit contains a switchable
slow/fast filter that has a 4.7 ms time constant. (Without filtering, the response is 10 :s) The filter
must be selected for AC inputs in order to eliminate response to zero crossings, however, it is
also valuable for use with slow DC signals in a noisy environment. A filter is individually selected
when a jumper is installed onto any of the positions ‘FILTER 0' thru ‘FILTER 7'.
The electro-mechanical relay outputs may be programmed individually or as an 8-bit byte. These
outputs may be latched, pulsed, or set to free-run for a prescribed period of time. The relays are
Form C, SPDT, and are de-energized at power-on.
A type 8031 microcontroller (with 8K x 8 RAM, 8K x 8 non-volatile EEPROM, and a watchdog timer
circuit) gives the WM-IIRO-8 the capability and versatility expected from a modern distributed control
system. To accommodate special programs, the RAM and EEPROM can each be expanded to 32K
x 8.
The built-in watchdog timer resets the pod if the microcontroller "hangs up". Data collected by the
pod can be stored in local RAM and accessed later through the computer's serial port. This
facilitates stand-alone operation.
The module, or pod, address is program mable from 00 to FF hex. W hatever address is assigned to
the pod gets stored in EEPROM and used as the default address at the next Power-ON. The use of
module addressing allows as m any as 256 W M-IIRO-8 units may be connected to a single host
computer & wireless serial modem.