LDM-100D Simulator

Serial Port Config

Baud Rate

Parity

Data Bits

Stop Bits

Device Addr (hex)

Response Delay (ms)

Interface Mode

Strips own TX echo from RX buffer automatically

Sensor Output Values

Soot Concentration (mg/m³)

110.6142

float32 BE → [25–28] → 42 DD 3A AE

Override Soot Bytes (hex, leave blank to use slider)

Paste exact bytes from real device capture. Overrides slider float conversion.
▶ 42 DD 3A AE (110.61) ▶ 40 C4 F5 1E (6.15)

Env Temperature (°C)

34.16

raw=1065−(T−25)×4096/1250 → [19–20] → 04 0B

LD Light Detect (0–65535)

26425

uint16 BE → [5–6] → 67 39

PD Photo Detect (0–65535)

36875

uint16 BE → [7–8] → 90 0B

Flow Velocity (m/s)

0.0000

float32 BE → [29–32] → 00 00 00 00

Current Loop (mA)

5.76

×100 uint16 BE → [33–34] → 02 40

Reserved [21–24] — 4 bytes hex

Normally 0. Try 00 00 C8 0E if vendor software still rejects.

Master

–

TX/A+

idle

RX/B–

Simulator

Offline

Response Timing

Rx→Decode

–

Delay

–

Total

–

Soot

–

mg/m³

Env Temp

–

°C

raw –

–

ADC

–

ADC

Flow

–

m/s

Loop

–

raw –

Last RX Command

–

Last TX Response

–

Frame Decoder ▶ Ref-0F ▶ Ref-10 ▶ Preview TX

Byte Diff — Working vs Generated ▶ Auto-fill

WORKING (known good):

GENERATED (simulator output):

IGN

ERR

Fault Injection

Add Noise

Slow Reply

Drop 40%

Bad Checksum

Truncate

No Response

Wrong Addr

Garbage

C9 Frame Map — 39 Bytes

[0]FA — start

[1]27 — total=39

[2–3]Device address

[4]C9 cmd echo

[5–6]LD uint16 BE

[7–8]PD uint16 BE

[9–10]Reserved (2B)

[11–12]AD4+AD7

[13–14]AD8

[15–16]0x00+AD5

[17–18]0x00+AD6

[19–20]EnvTemp uint16 BE ★

[21–24]Reserved (4B) configurable

[25–28]Soot float32 BE ★

[29–32]Flow float32 BE

[33–34]Loop×100 uint16 BE ★

[35–36]Reserved (2B)

[37]CHK = Σ[1..36]&FF ★

[38]F5 — end

RS232 Echo Cancellation

How it works:

On RS232 full-duplex, every TX byte echoes back on RX.

Without cancel:
RX sees: FA 00 0F C9 FF 00 D1 FA 27 00 0F…
Parser gets confused by own echo.

With cancel:
TX echo stripped from RX buffer.
Vendor SW receives clean response.

All Commands

0xC9 Return test results (39B)

0x98 Read system params (63B)

0xCE 0x97 0x8C 0x9E

0xA5 0x9D 0x9A 0xCF 0xD0

↑ All return 11B stub ACK