Danfoss AK-SC255 - Communication and Network Issues; I;O Communication Failure; Scanning and Network Failure

1.0 Intended application (Hardware / Software)
The following important points dene the intended application scope for a Com-Trol (local bus) retro-t installation. Please
read these fundamental requirements before continuing.
• One Com-Trol 4K/4K2e should be replaced with one Danfoss AK-SC255 unit
• The Danfoss AK-SC255 RS-485 (Modbus) port is used for communication to the Com-Trol I/O boards (gure 1). Host
communication to other AK -SC255 and/or AK-SC255 Loggers must be done via the Ethernet port.
• Only one local bus loop can be connected to the AK-SC255 (gure 1) - No star wiring congurations allowed
• Valid local bus termination and wiring rules must be applied and maintained (see gure 3 below)
• Existing system capacity for number of Com-Trol I/O boards (dened by Com-Trol documentation) must be maintained
• AK-SC255 software version R2.151 and above must be used in order to provide Com-Trol support
• The AK-SC255 being used in the application must have a valid Com-Trol license installed. If a license is required contact
Danfoss Customer service on 410-931-8714 with the AK-SC255 MAC address
Power Connection
(100 - 240 V a.c.)
LonWorks© Port(s)
RS485 Modbus - Used for COM-Trol local bus
Alarm Relay
External Modem
Port
Ethernet
Fuse (1 Amp) 30 V d.c.
Direct
Connect
Port
Door latch
CPU Card
Battery
Battery Jumper
circuit
Address
Switch
Figure 2- AK-SC255 Internal port and connection layout
Figure 3- Com-Trol recommended wiring standard
(extract from Com-Trol MCS-4xxx and 4K2e Install manual (F-27262-4)