User Manual

Configuring the Adapter 3-9
20-COMM-H RS-485 HVAC Adapter User Manual
Publication 20COMM-UM009D-EN-P
Viewing the Adapter Status
Using Parameters
The following parameters provide information about the status of the
adapter. You can view these parameters at any time.
Parameter Description
04 - [Net Add Act] Displays the actual network address of the adapter.
06 - [Net Rate Act] Displays the network data rate actually used by the adapter. Only valid
values for the specified network are displayed.
08 - [Net Parity Act] Displays the actual network parity used by the adapter. Only valid values
for the specified network are displayed.
09 - [Stop Bits Act] Displays the actual number of stop bits used by the selected protocol.
This value is network-dependent:
• ModBus RTU Protocol – The number of stop bits used depends on the
value set by Parameter 30 - [Stop Bits Cfg]). If the value is “0,” the
adapter uses 1 stop bit; otherwise, it uses 2 stop bits.
• Metasys N2 Protocol – Uses only 1 bit, so the adapter shows only this
value.
• Siemens Building Technologies P1 FLN Protocol – Uses only 1 bit, so
the adapter shows only this value.
10 - [Net Chksum Type] Displays the type of checksum used by the selected protocol. The values
are as follows:
• CRC16 (0) is Cyclic Redundancy Check with 0 as a seed value. The
Siemens Building Technologies P1 FLN protocol uses this checksum.
• RLC is Run Length Checksum. The Metasys N2 protocol uses this
checksum.
CRC16 (-1) is Cyclic Redundancy Check with -1 as a seed value. The
Modbus RTU protocol uses this checksum.
17 - [DPI I/O Act] Displays the Reference/Feedback and Datalinks used by the adapter. This
value is the same as Parameter 16 - [DPI I/O Cfg] unless the parameter
was changed and the adapter was not reset.
Bit
Definition
Not Used Not Used Not Used Datalink D Datalink C Datalink B Datalink A Cmd/Ref
Default xxx00001
Bit 76543210
0 = I/O disabled
1 = I/O enabled