Factory Line - Wireless LAN
3-52
PHOENIX CONTACT
7190_en_02
–
16 (0x10) Write Multiple Registers
–
3 (0x3) Read Holding Registers
Valid read requests for APs and clients for "Read Holding Registers" functions:
–
Current number of dialed-in stations
–
Current receive level, transmit level, and MAC address of all dialed-in stations or of the
AP for a client.
Table 3-3
Modbus request for the current number of dialed-in stations
Request
Function code
0x03
Starting address
0x2
Quantity of registers
1
Table 3-4
Modbus response for the current number of dialed-in stations
Request
Function code
0x03
Starting address
0x2
Register value
2 bytes
The return value corresponds to the current number of dialed-in stations with a size of
2 bytes each. A maximum of 256 stations can be included in the list. For a client, the value
is always 1.
Table 3-5
Modbus request for the current number of dialed-in stations
Request
Function code
0x03
Starting address
0x3, 0x80
Quantity of registers
1 - 125 (N)
Table 3-6
Modbus response for the current receive level, transmit level, and MAC
address
Request
Function code
0x03
Starting address
2 x N
Register value
N x 2 bytes
The return value contains 8 bytes per station (4 registers wide). Bytes 1 to 6 contain the
MAC address of the station. Byte 7 contains the RSSI receive level and byte 8 contains
the current transmission power for this station.
The first 125 stations are from address 0x2 onwards, and the next 125 stations are from
address 0x80 onwards. If fewer stations are available, the registers are filled with 0x0. For
a client, there is only one value at address 0x36, which applies for the access point used.
