1838-066-E-12-16
13
ON
ON
RS-485 Configurations
RS-485 Device Addresses
Termination Switches
4000 ft Maximum (3/4 Mile)
CORRECT Configuration Samples
INCORRECT Configuration
4000 ft Maximum (3/4 Mile)
ON
ON
SW2
Terminated
End Device
Address
003
Term Sw
OFF
Address
003
Term Sw
ON
Terminated
End Device
Terminated
End Device
Terminated
End Device
Terminated
End Device
Address
004
Term Sw
OFF
Address
003
Term Sw
Term Sw
Term Sw
Term Sw
OFF
Address
004
Term Sw
OFF
Address
005
Term Sw
OFF
Address
006
Term Sw
OFF
Address
007
Term Sw
Terminated
End Device
ON
Address
008
Term Sw
ON
Terminated
End Device
Address
003
Term Sw
ON
Terminated
End Device
Address
004
Term Sw
OFF
Address
003
Term Sw
OFF
Address
006
Term Sw
OFF
Address
005
Term Sw
ON
Terminated
End Device
Address
004
Term Sw
ON
Terminated
End Device
Address
007
Term Sw
ON
Terminated
End Device
Address
008
Term Sw
OFF
Address
003
Term Sw
OFF
Address
004
Term Sw
OFF
Address
005
Term Sw
OFF
Address
006
Term Sw
Terminated
End Device
ON
Address
007
Term Sw
1
ON
Terminated
Device
Address
005
Term Sw
2 Devices “Daisy Chain”
OFF
Address
004
Term Sw
Address
008
Term Sw
OFF
Address
003
Term Sw
Address
003
Term Sw
Terminated
End Device
ON
Address
004
Term Sw
ON
Address
007
Term Sw
Internal Addresses
001
for Relay 1
002
for Relay 2
(Factory Set)
Maximum of two (2)
terminated end
devices allowed.
Maximum of six (6)
RS-485 devices allowed.
Any RS-485 Keypad,
Card Reader,
MicroPlus RF
Receiver and Access
Plus system “Daisy
Chain” wiring
sequence allowed.
Access Plus system on
end of “Daisy Chain”
wiring sequence has the
strongest signal strength.
The Access Plus system can be wired in the middle of the “Daisy Chain” if needed. It is
important that the distance restriction (4000 ft) be observed and that the devices at the end
of the chain have their termination switches
ON.
The devices in the middle of the chain have
their
termination switches turned
OFF
.
Every RS-485 device (keypad, card reader, MicroPlus RF
receiver) must have a unique address assigned to it, starting
with 003. The address selector switches are located on the
RS-485 circuit board (see instruction sheets that come with
each RS-485 device). The address order of the devices
connected to the 1838 does not matter. What is important is
that the addresses must be numbered in sequence.
Do not
skip a number in the address sequence and start the
sequence with 003
(e.g. If three (3) RS-485 devices are daisy chain wired to the
1838 and their addresses are 003, 004 and 006, this is wrong.
They must be addressed 003, 004 and 005).
The 2 internal relays on the 1838 circuit board are 001 and
002.
Valid RS-485 external device addresses for use with
the 1838 are 003, 004, 005, 006, 007 and 008.
Important Note:
The device address is referred to as a
“Relay Number” in the programming software.
A termination switch is located on
every
circuit board. The
termination switch must be
OFF
for every device wired in
the middle of the daisy chain. The devices at each end of
the daisy chain must have their termination switches
ON
.
Some Configuration Problems to Avoid:
The total distance for the complete wire run is greater than
4000 ft.
There are more than 6 RS-485 devices.
There are more than 2 wire runs coming out of the 1838.
There are more than 2 end devices
terminated and/or incorrect end device
terminations (Not turned
ON
).
There are more than 6 addresses and/or
duplicate or skipped addresses.
An RS-485 device can not have 2 RS-485
devices separately continued from it.
The 1838 must have it’s SW2 termination
switch turned OFF when 2 terminated end
devices are being used.
2
1
2
3
4
4
4
4
5
5
5
6
7
6
7
ON
ON
SW2
ON
SW2
Internal Addresses
001
for Relay 1
002
for Relay 2
(Factory Set)
OFF
SW2
FF
Term Sw
Internal Addresses
001
for Relay 1
002
for Relay 2
(Factory Set)
OFF
SW2
FF
Term Sw
Internal Addresses
001
for Relay 1
002
for Relay 2
(Factory Set)
OFF
SW2
FF
Term Sw
ON
SW2
Term Sw
3
“Daisy Chain”
End
“Daisy Chain”
End
“Daisy Chain”
End
“Daisy Chain”
Middle
“Daisy Chain”
Middle
“Daisy Chain”
Middle
Access Plus
Access Plus
Access Plus
Access Plus
Access Plus
Access Plus
ON
OFF
FF
0
9
8
7
6
5
4
3
2
1
0
9
8
7
6
5
4
3
2
1
1
0
0
0
3
BOARD ADDRESS
First Rotary Switch
Toggle
Switch
Second Rotary Switch
Setting Board Address
Summary of Contents for 1838 Access Plus
Page 39: ...1838 066 E 12 16 35...
