10
KWE P
/N 3940
46 Ve
rsatronik
502 a
nd 502D
MODBUS G
atewa
y V1
.0 F
eb
2
014 Te
chni
ca
l i
nformation subj
ec
t to
ch
ange
w
ithout noti
ce
3
Connection Overview—120VAC
Communication connections—Vitocontrol-S, CT3/VD2A
Modbus
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+
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Modbus
communications
120VAC
4
Refer to manual specific to boiler/
system control. Ensure necessary LON
communication card installed.
1 A 3’/91cm CAT-5 cable is supplied
with the gateway. The RJ45 is
plugged into the control and
terminates into the RJ45 socket
inside of the Versatronik 502
gateway.
Vitocontrol-S will need LON card
installed.
2 Versatronik 502 gateway.
3 Field wiring for Modbus connection
to terminals A and B.
4 Plug-in power cord for 120VAC
Versatronik 502 gateways.
Connection Overview
1
2
Modbus Wiring Connections
(RS-485 Network)
COM 1 terminals A and B are used. It is
to be noted that the A/B naming conven-
tion may differ across manufacturers.
A=(+) non-inverting
B=(—) inverting
Termination and Bias:
This device does not have a termination
resistor installed. There are two weak
(4.7Kohm) pull up/down resistors located
on the lines to maintain a bias.
Modbus Wiring Connections