Ethernet Tcp/Ip Functions; Function 3 (3Hex): "Read Multiple Registers; Function 16 (10Hex): "Write Multiple Registers - Pepperl+Fuchs VBG-ENXK20-DMD-EV Manual

AS-i 3.0 EtherNet/IP+Modbus TCP Gateway
Operation via Ethernet IP (Modbus/TCP)
Information!
Checksum fields are not needed, because the TCP/IP and link layer (eg. Ethernet)
instad are used to verfiy accurate delivery of the packet.
Example transaction:
Read 1 register at offset 4 from UI 9. Return value is 5
request
response
12.2

Ethernet TCP/IP functions

In the following chapter are shown the support functions. Please note, that only
the related bytes are shown (bytes 0 - 3 are let away, because the values are 0).
12.2.1

Function 3 (3hex): "Read multiple registers"

This function allows to read the value of read/write-registers.
request:
response:
12.2.2

Function 16 (10hex): "Write multiple registers"

This function allows the setting of several read/write-registers:
request:
response:
80
00 00 00 00
00 00 00 00
3 R1 R2 N1
high low high
3 B D1 D1
high low
R1/R2: reference number (high byte / low byte)
N1/N2: word count (range 1 - 125) (high byte / low byte)
response:
B: byte count of response (b = 2 x word count)
D: register values
10 R1 R2 N1
high low high
10 R1 R2 N1
high low high
R1/R2: reference number (2 byte hex-value of register
e.g. 8192 = 0x2000)
N1/N2: Word count (1 - 100) (2 byte)
B: byte count of response (B = 2 x word count / 1 byte)
(redundant information to word count but necessary).
D1 ... Dn: register values
00 06 09 03
00 05 09 03
N2
low
... Dn Dn
high low
N2 B D1 D1
low high low
N2
low
00 04 00 01
02 00 05
... Dn Dn
high low