1) Resolution K vs. Minimum Detectable Size

Definition. In DAIDISIKE measuring gratings, K is the beam pitch (mm). The smaller the pitch, the smaller the reliably detected rod, edge, hole, or part.

Rule-of-thumb. For opaque targets, a conservative sizing is: Minimum object size (mm) ≥ 1.2 × K. For hole/slot inspection, use Minimum hole diameter (mm) ≥ 1.5 × K to maintain stability under vibration and misalignment.

Available K options in DQL/DQM: 2.5, 5, 10, 20, 40, 80 mm (check your local datasheet for exact availability per model length).

2) How to Size Protective Height H

Protective height (active measuring window) must fully cover the target envelope plus guard margin for installation tolerances.

Sizing formula. H ≥ Target span along light curtain + 2 × K (adds top/bottom margin approximately one beam pitch each). In most DQL/DQM models, mechanical length L relates to H by: L ≈ H + 30 mm (end caps & mounting).

Select the next higher standard model length. For multi-height scenarios (e.g., mixed cartons), choose H for the largest case or deploy two graded curtains.

3) Line Speed & Response Time Check

To avoid miss-counts on fast conveyors, ensure the beam interruption time exceeds the curtain's response time.

Check. Let v be line speed (m/s) and s the object length in travel direction (mm). The single-beam dwell time is t ≈ (s + K) / (1000 × v) seconds. Require t ≥ τ, where τ is the light curtain response time. DAIDISIKE DQL/DQM typically support 0.5–5 ms; use 5 ms as a conservative design value.

When t < τ, enable anti-jitter filtering, widen K, or increase the detected span (use two beams, virtual gate, or dual-curtain crossing).

4) Quick Application Matrix (DAIDISIKE DQL/DQM)

Matrix is indicative; always validate with onsite samples and ambient-light/reflectance conditions.

1) Terminals & Recommended Wiring

2) Example Modbus Register Map (DQL/DQM)

Actual maps may vary by firmware. DAIDISIKE can provide the register list for your exact DQL/DQM build and length.

3) PLC Code — Structured Text (IEC 61131-3) to Poll DQL/DQM (Modbus-RTU Master)

// DAIDISIKE DQL/DQM Modbus Read (ST), generic master FB
// Assumes a library FB 'MB_Master' with .Execute, .ReadHoldingRegs, .WriteSingleReg
VAR
  mb         : MB_Master;
  readOK     : BOOL;
  regs       : ARRAY[0..9] OF UINT;   // buffer for 10 holding registers
  modelCode  : UINT;  // 40001
  k_x10      : UINT;  // 40002
  span_x10   : UINT;  // 40010
  count      : UINT;  // 40012
  status     : UINT;  // 40014
  dwell_ms   : REAL;
END_VAR
// Init (once): configure serial port of COMx to 9600-8-N-1, RTU mode
// mb.Port := COM1; mb.Baud := 9600; mb.Parity := 0; mb.StopBits := 1; mb.SlaveAddr := 1;
(* Read 10 registers starting at 40001 (= index 0 if the FB takes zero-based) *)
mb.ReadHoldingRegs(Slave:=1, StartAddr:=40001, Quantity:=10, pData:=ADR(regs));
readOK := mb.Execute();
IF readOK THEN
    modelCode := regs[0];
    k_x10     := regs[1];
    span_x10  := regs[9 - (10 - (40010-40001))]; // or simply map by absolute address
    span_x10  := regs[9 -  (40010-40001)];       // adjust per your FB buffer indexing
    count     := regs[11 - (40012-40001)];       // example; replace with your platform's mapping
    status    := regs[13 - (40014-40001)];
    // Example: Reset counter when DO2 (oversize) goes high -> write 0xA55A to 40021
    IF (status AND 2#0000_0010) <> 0 THEN
        mb.WriteSingleReg(Slave:=1, Addr:=40021, Value:=16#A55A);
        mb.Execute();
    END_IF;
END_IF;
// Helper conversions
FUNCTION K_mm : REAL
VAR_INPUT k_raw : UINT; END_VAR
K_mm := REAL(k_raw) / 10.0;
FUNCTION Span_mm : REAL
VAR_INPUT s_raw : UINT; END_VAR
Span_mm := REAL(s_raw) / 10.0;

Each PLC brand names its Modbus FBs differently (e.g., MB_MASTER / MODBUS_RTU / MBUS). Map StartAddr and buffer indices to your vendor's convention (zero-based vs. 40001-based).

4) MES/IPC Snippet — Python (pyModbus) to Log Measurements

# DAIDISIKE DQL/DQM Modbus-RTU readout (Python 3.x)
from pymodbus.client import ModbusSerialClient
from datetime import datetime
import csv

client = ModbusSerialClient(
    method="rtu", port="/dev/ttyUSB0", baudrate=9600, parity="N", stopbits=1, bytesize=8, timeout=0.2
)
assert client.connect(), "Cannot open serial port"

def read_block(unit=1, start=0, count=10):
    rr = client.read_holding_registers(address=start, count=count, slave=unit)
    if rr.isError(): raise RuntimeError(rr)
    return rr.registers

with open("daisidike_dql_dqm_log.csv","a", newline="") as f:
    w = csv.writer(f)
    regs = read_block(unit=1, start=0, count=24)   # start=0 ≈ 40001 on many stacks
    model   = regs[0]
    k_x10   = regs[1]
    span10  = regs[9]   # adjust indices to your stack's mapping
    count   = regs[11]
    status  = regs[13]
    ts = datetime.utcnow().isoformat()
    w.writerow([ts, model, k_x10/10.0, span10/10.0, count, status])
    print("OK", ts)

Use an industrial USB-RS485 adapter or native RS-485 port. For Windows, set port="COM3". For long lines, prefer 19200 or 38400 only if your EMC budget allows.

5) Analog Scaling — From AI Counts to millimeters

// Siemens/TIA example (LAD/ST): 4–20 mA, raw 5530..27648
SPAN_mm := (REAL(AI_raw) - 5530.0) * H_MAX_mm / (27648.0 - 5530.0);
IF SPAN_mm < 0.0 THEN SPAN_mm := 0.0; END_IF;

// 0–10 V scaling to millimeters
SPAN_mm := REAL(AI_raw) * H_MAX_mm / 27648.0;

6) Commissioning Checklist (Production Line)

• ✓ RS-485 polarity verified (A+ to A+, B− to B−), 120 Ω at both ends, bias at master.
• ✓ PLC master can read 40001..; model and K values make sense; status toggles with a test piece.
• ✓ Analog span matches H_MAX_mm; overshoot/undershoot alarms tied to DO outputs.
• ✓ Response time vs. line speed validated (beam dwell ≥ τ); filtering tuned, no missed counts.
• ✓ MES log shows timestamped span/count; daily CSV/DB roll-over implemented.