Exporting to CSV synphasor (PMU) data

edit

You could use a Lua script to create a new field and format the data as needed.
(See example: How to change the info column in a protobuf dissector.)

-- EASYPOST.lua
-- Replace occurrences of "easypost/EASYPOST" with protocol/dissector name.
-- Grab and format fields as needed

-- Step 1 - document as you go. See header above and set_plugin_info().
local easypost_info =
{
    version = "1.0.0",
    author = "Good Coder",
    description = "Important EASYPOST stuff",
    repository = "Floppy in top drawer"
}

set_plugin_info(easypost_info)

-- Step 2 - create a protocol to attach new fields to
local easypost_p = Proto.new("easypost","Important EASYPOST Protocol")

-- Step 3 - add some field(s) to Step 2 protocol
local pf = { payload = ProtoField.string("easypost.payload", "EASYPOST data") }

easypost_p.fields = pf

-- Step 4 - create a Field extractor to copy packet field data.
-- easypost_payload_f = Field.new("frame.protocols")
easypost_payload_f = Field.new("synphasor.phasor")

-- Step 5 - create the postdissector function that will run on each frame/packet
function easypost_p.dissector(tvb,pinfo,tree)
    local subtree = nil

    -- copy existing field(s) into table for processing
    finfo = { easypost_payload_f() }

    if (#finfo > 0) then
        if not subtree then
            subtree = tree:add(easypost_p)
        end
        for k, v in pairs(finfo) do
            -- process data and add results to the tree
            field_display = string.gsub(v.display, "^[^,]+,[ ]+", "")
            subtree:add(pf.payload, field_display)
        end
    end
end

-- Step 6 - register the new protocol as a postdissector
register_postdissector(easypost_p, true)

Using the sample file mentioned above. (Profile specified to get needed DLT config info.)

C:\>"c:\Program Files\Wireshark\tshark.exe" -C 250408_missing_experts -r 351S_synphasor_serial.pcap -V -Y frame.number==651 -T fields -e easypost.payload -E aggregator="|"
11.270A ∠-26.053° alt  10.125+j -4.950A; unscaled:    45,   -22|4.528A ∠-26.565° alt   4.050+j -2.025A; unscaled:    18,    -9|4.227A ∠-25.201° alt   3.825+j -1.800A; unscaled:    17,    -8|1.677A ∠-26.565° alt   1.500+j -0.750A; unscaled:    20,   -10|5.909V ∠-23.962° alt   5.400+j -2.400V; unscaled:     9,    -4|7.250V ∠-24.444° alt   6.600+j -3.000V; unscaled:    11,    -5|7.250V ∠-24.444° alt   6.600+j -3.000V; unscaled:    11,    -5|7.250V ∠-24.444° alt   6.600+j -3.000V; unscaled:    11,    -5|2.216A ∠-23.962° alt   2.025+j -0.900A; unscaled:     9,    -4|0.000V ∠  0.000° alt   0.000+j  0.000V; unscaled:     0,     0

The string.gsub() above deletes text up to the , and spaces before next non-space character.
To get the remainder (including the ;) it might be easier to read as two steps:

            -- process data and add results to the tree
            field_display = string.gsub(v.display, "^[^,]+,[ ]+", "")
            field_display = string.gsub(field_display, ";.+$", "")
            subtree:add(pf.payload, field_display)

C:\>"c:\Program Files\Wireshark\tshark.exe" -C 250408_missing_experts -r 351S_synphasor_serial.pcap -V -Y frame.number==651 -T fields -e easypost.payload -E aggregator="|"
11.270A ∠-26.053° alt  10.125+j -4.950A|4.528A ∠-26.565° alt   4.050+j -2.025A|4.227A ∠-25.201° alt   3.825+j -1.800A ...