Selector Switch
Settings:
The function and
address of the WIEG-EXT module is selected via the Selector switch SW1.
When Switch 1 is set ON it defines the unit as being a master unit with
address 0000. There must always be one unit set as a master unit in any
network of units. Other than having control functions the Master unit
will behave as a Sender unit at address 0000.
When switch 2 is set ON it defines the unit as being a Sender unit of
which the address is defined by the switch setting at positions 3 to 6.
Sender units output the wiegand data received from the Remote units, as
well as controlling the I/O lines and on board Relay of the Remote
units.
When switch 2 is set OFF it defines the unit as being a Remote unit of
which the address is defined by the switch setting on positions 3 to 6.
Remote units collect wiegand data and send the information to their
matching Sender units. Additionally the on board relay on the Sender
units may be controlled via the Relay control line on the Remote unit.
Similarly the on board relay of the Remote unit is controlled by the
Relay control line on the Sender unit.
General Operation:
Master Units:
A single pair of cable using RS485 protocol communications is only
capable of using half duplex protocol for all data transfer on the
line. For this reason a Master unit is required to coordinate data
transfer between all units on the bus. Setting switch 1 on the Switch
selector will designate a unit as the Master.
On power up the Master unit will scan the RS485 bus to determine which
Sender and Remote units are connected. This allows it to build up an
image of the complete network so that time is not wasted
polling
units that are not connected. Up to 16 Remote units, 15 Sender units,
and the Master can exist on a single RS485 bus network. The Master unit
also operates as a Sender unit with the address 0000.
The minimum size network that can exist comprises of one Master unit
and one Remote unit at address 0000.
Every 20 seconds the Master unit will rescan the network to see if any
new units have been added or removed from the network.
Remote Units:
The remote units allow a keypad, card Readers, or any wiegand device to
be connected. Wiegand data streams are collected of any length up to 45
bits. When a delay is encountered after the data stream is received the
unit assumes that the wiegand data is complete and signals the network
that data is ready to be transmitted. The on board led will illuminate
to indicate that data is waiting to be sent.
When the RS485 bus is free of traffic the Master unit will signal the
Remote unit to send its data to the corresponding Sender unit with the
same switch address. When the Sender receives the data it then
recreates the wiegand stream as detected by the Remote unit and outputs
it in standard wiegand format for the access control system to receive.
At this point the on board LED on the Remote unit will de-activate to
indicate that data has been sent.
Each Remote unit has a relay for external control of peripherals. It
can be activated with an active low signal at the RELAY IN input
located on the matching Sender unit. Similarly the Relay located on the
matching Sender unit can be activated with an active low signal to the
RELAY IN input of the Remote unit.
Connectors J1 and J2 include an I/O OUT output. This is an open
collector output commonly used to activate a LED on a keypad, or give
some other feedback response. This output activates when the I/O IN
signal located on the matching Sender unit becomes active low.
Similarly the I/O OUT on the matching Sender unit can be activated with
an active low signal to the I/O IN input on the Remote unit.
Sender Units:
Sender units are used to collect wiegand data sent by the Remote units
and to output it in standard wiegand format to the receiving access
controller. Wiegand data streams are sent in exact format as received.
Parity bits are not checked and are transmitted as received.
Each Sender unit has a relay for external control of peripherals. It
can be activated with an active low signal at the RELAY IN input
located on the matching Remote unit. Similarly the Relay located on the
matching Remote unit can be activated with an active low signal to the
RELAY IN input of the Sender unit.
Connectors J1 and J2 include an I/O OUT output. This is an open
collector output commonly used to activate a LED on a keypad, or give
some other feedback response. This output activates when the I/O IN
signal located on the matching Remote unit becomes active low.
Similarly the I/O OUT on the matching Remote unit can be activated with
an active low signal to the I/O IN input on the Sender unit.
