The following chapter describes the available connections on
your AK-SM 850.
Please note that not all connection points are currently
active, please refer to the drawing below for more details
Connections
Your AK-SM supports both Modbus and Lon RS485 local bus
connections. For further detailed description of network
connections please refer to document ‘
Data Communication
between ADAP-KOOL® Refrigeration controllers_RC8AC602
’
Lon RS485
Follow standard topology guidelines for Lon RS485, with
particular respect to maximum cable length, when to use a
repeater and ensuring suitable resistors are in place.
Network topology
Power Supply
Alarm relay
not currently
used
not currently
used
Boot switch
(used to place unit in
boot loader mode)
Address swicth
(used when configuring
multiple SM units
Modbus field
bus
Lon (RS485)
field bus
Cable type
Cables twisted in pairs must be used, and they may be provided
with a screen. Some types of communication require a cable with
a screen to be used. The conductor’s cross section must be at
least 0.60 mm. Examples of cable types:
Belden 7701NH, single-thread 1 x 2 x 0.65 mm, without screen
Belden 7702NH, single-thread 2 x 2 x 0.65 mm, without screen
Belden 7703NH, single-thread 1 x 2 x 0.65 mm, with screen
Belden 7704NH, single-thread 2 x 2 x 0.65 mm, with screen
LAPP UNITRONIC Li2YCY (TP), multi-thread 2 x 2 x 0.65 mm, with
screen
Dätwyler Uninet 3002 4P, single-thread 4 x 2 x 0.6 mm, with
screen
When using the Lon RS485 network, ensure the
Term. Switch on the AK-SM is in the ‘ON’ position
(enable internal resistor). Any repeaters must
also have 120 Ohm resistor in place. Finally, en-
sure that the last controller on the network run
also has its end of line on line resistor enabled.
RJ 45 LAN, Use shielded Ethernet cable
8
User Guide
Lit. no.
USCO.PI.R1.E1.02 © Danfoss 07-2013
AK-SM
850