Acces WM-IIRO-8 User Manual - Chapter 1: Introduction
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Man ual W M-IIRO -8
Chapter 1: Introduction
Features
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RS2 32 Serial Interface to Host Co m puter.
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900 MHz W ireless Connection Between Host Computer Modem and W M-IIRO-8.
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8 Optically-Isolated, Non-Polarized Digital Inputs with Change of State(COS) Detection.
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8 SPDT Electro-Mechanical Relay Outputs that Switch Up to 1 Amp Each.
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Digital Outputs May Be Either Level or Pulsed.
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Type 8031 Microc on troller w ith 8 K R AM and 8K E EP ROM. (32K X 8 option al)
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Ability to Program with Custom Firmware over W ireless Connection
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NEMA 4 Enclosure for Harsh Atmospheric or Marine Environments.
Functional Description
The W M-IIRO-8 is an intelligent 8-bit parallel digital I/O unit that comm unicates with ACCES’s
W ireless Serial Modem via a 900 MH z wireles s co nne ction. T he W ireless Serial Mo dem con nec ts
to a host com puter’s standard C OM port using an RS232 (or RS485) serial com m un ica tion s protoc ol.
Both the W M-IIRO -8 and the W ireless Serial Modem are packaged in NEMA4 enc losures for re m ote
installation in harsh environments. ASCII-based comm and/response protocol permits comm unication
with virtually any co m pute r syste m . It can operate at bau d rate s up to 9600 b aud at dista nce s up to
7 m iles line-o f-sigh t.
Th e 8 iso lated inputs can be d riven b y either A C o r DC signa ls and are n ot po larity sens itive.
Input signals are rectified by photocoupler diodes. Standard 12/24 AC control transformer
outp uts c an b e ac cep ted a s we ll as DC voltag es. T he inp ut voltage ra nge is 3 to 28 volts (rm s).
Unused power dissipates through a 1.8KS resis tor. Ex terna l resisto rs conn ecte d in se ries w ith
this m ay be use d to exten d th e inpu t voltag e ra ng e. E ac h inpu t circu it co nta ins a switc ha ble
slow/fast filter that has a 4.7 ms time constant. (W ithout filtering, the response is 10 :s) The filter
must be selec ted for AC inputs in order to e lim inate res po ns e to zero cross ings, h ow ever, it is
also valuable for use with slow DC signals in a noisy environment. A filter is individually selected
wh en a jum per is ins talled onto any of the position s ‘FILT ER 0' thru ‘FILT ER 7'.
The electro-mechanical relay outputs may be programm ed individually or as an 8-bit byte. These
outputs m ay be latched, pulsed, or set to free-run for a prescribed period of time . The relays are
Form C, S PD T, a nd a re de -ene rgized at power -on.
A type 8031 microcontroller (with 8K x 8 RAM, 8K x 8 non-volatile EEPROM, and a watchdog timer
circu it) gives the W M-IIRO-8 the capability and versatility expected from a m odern distributed control
system. To accom modate special programs, the RAM and EEPR OM 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
po d can be sto red in local R AM and acc es se d later throu gh the com pu ter's s erial port. This
facilitates stand-alone operation.
The module, or p od , ad dres s is pro gram m ab le from 00 to F F h ex . W ha tever addres s is ass igned to
the pod gets stored in EEPRO M and used as the default address at the next Power-ON. The use of
m od ule add ressing allows as m any as 256 W M- IIRO -8 un its may be connected to a single host
computer & wireless serial modem .