I’ve produced a (slightly updated) table of Samsung NASA message numbers, mainly for my own reference, but which may be useful to others:
NASA_Interpreter.xlsx (71.7 KB)
This table only includes:
- message numbers included and described in NASA.ptc (a file included with SNET-Pro2 software) and
- messages that I have detected on my MIM-E03EN F1/F2 data highway
(Not all the NASA.ptc messages appear on F1/F2 – I assume that these have been configured for controllers other than the MIM-E03EN.)
The worksheet includes the following columns:
A NASA message number 0xnnn in alphanumeric order
B Message type (E = enumeration, V = variable (2 bytes), L = long variable (4 bytes), S = structure)
C Whether the message appears in NASA.ptc (and thus accessible to SNET-Pro2)
D Whether reported in default SNET-Pro2 tabulation
E Whether reported in NASAmonitor display
F Message payload content description (fields in quotes refer to SNET-Pro2 tabulation entries)
G Variable name assigned (“Protocol ID”) by NASA.ptc
H Whether 2’s complement applied for payload evaluation (negative numbers)
I Divisor to be applied to payload to derive actual value
J Frequency at which message appears on F1/F2 data highway (seconds) (see note below)
K Payload value ( may be hex 0xn… for enum, integer if constant, V if varying, SNET = appears on SNET start-up or FSV update request)
L Comments
FSVs
Most FSVs have been assigned a message number, with any new values written directly to that number (which is routinely parsed by the controller). However, #4054, #4062/3, and #6022/31/41 are handled slightly differently. Any new values for these are written to 0x4612 (the FSV Information Table, which contains the Min/Max/Default values seen in the User Manual) by changing the Default value in this table. (FSV values are written to EEPROM, which is read by the controller at start-up and updated on demand, e.g. from the remote controller or SNET or Modbus.)
Unverified Message Numbers
Many of the non-NASA.ptc messages received from the MIM-E03N (at least when connected to an HTQ series ASHP) appear to be unvarying and thus unhelpful. However there are some that do vary (e.g. 0x22F7, 0x22FB, 0x22FC, 0x22FE, 0x24FC, 0x8224, 0x824C). Also, although 0x827A appears on NASA.ptc as Desuperheater temperature, and the payload varies, the location of this instrument on the PFD is not obvious. If anybody has any insights on either of these matters it would be very helpful.
The data arrival frequency of some messages varies tremendously (depending on what’s going on in the heat pump), so the figures in the table should be regarded as a guide only.
NASA Packet Decoder
I’ve added a simple worksheet to decode NASA packets and included this on a separate tab. This is based on the EHS Wiki NASA protocol disassembly document (posted elsewhere on this forum).
To use this decoder, simply paste a data packet into cell B3. The worksheet splits the packet into individual NASA messages and evaluates the payload for each.
These packets can be copied from a VCOM monitor output. For example, copying Packet #18 from this VCOM output…
…and pasting it into cell B3 of the worksheet, results in this decoding:
(Obviously the compressor was not running when I took this screenshot – suction and discharge pressures are roughly the same, and the compressor current is zero.)
Any comments on the foregoing would be welcome…