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15 DF1 AND ETHERNET/IP PROTOCOL SUPPORT
DF1. The EtherMeter provides elementary support for Rockwell Automation’s DF1 serial
protocol. This manual assumes that the user is well-versed in the DF1 Protocol. In order to learn
more about the DF1 protocol, visit rockwellautomation.com.
The following functional subset of the DF1 protocol is supported by the EtherMeter:
[CMD,FNC] = [0F,A2] - “Protected Typed Logical Read With 3 Address Fields”
[CMD,FNC] = [0F,AA] - “Protected Typed Logical Write With 3 Address Fields”
To a polling master PLC or computer, the EtherMeter’s data is available within the Integer and Bit
registers documented within this section. Read-only, Integer data is stored within the N7:0
register, and read-only Bit data is stored within B250 registers. The two (2) auxiliary digital
outputs are mapped to the N10:0 register. When addressing Bit registers, is important to note
that misaligned bit blocks, partial words, and masked/scattered bit reads are not supported.
DF1-RadioModem and DF1-FullDuplex are both supported; and DF1-HalfDuplex is not
supported. For error checking, either CRC-16 or BCC error checking may be selected.
In the DF1 protocol, the byte-order is “low-byte / high-byte” and the word order is “low-word /
high-word”. This method of ordering is also known as “Little-Endian”. The DF1 byte-order and
word-order are fixed within the EtherMeter. To ensure Allen-Bradley compatibility, DF1 and
EtherNet/IP byte and word ordering cannot be modified through the Setup Menu.
To test and/or verify DF1 communications with the EtherMeter, there are several useful computer
programs available. SCADAmetrics recommends KepServerEx from Kepware Technologies
(kepware.com
), or RSLinx™ from Rockwell Automation (rockwellautomation.com). Assistance
and support for these programs (and all 3
rd
-party software) may be obtained from their respective
manufacturers.
KepServerEx (Kepware Technologies)
RSLinx (Rockwell Automation)
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