XinJe_PLC_Skill/references/plc-hmi-integration-patterns.md

PLC-HMI Integration Patterns

Use this P3 reference for practical PLC/HMI linking: address allocation, command/status separation, screen switching, alarms, parameter writes, and commissioning tables.

Source anchors:

• TouchWin manual PDF page 38: PLC-register-controlled screen change and current screen report.
• TouchWin manual PDF pages 75-77: HMI button/indicator-button objects and warning about PLC direct OUT to the same bit operated by HMI.
• TouchWin manual PDF pages 82-88: data display/input, scaling, and HMI writes to lower-device registers.
• XDPPro software manual PDF pages 130-132: data monitoring can modify coils/registers; use cautiously during commissioning.
• soft-elements-and-special-relays.md and ladder-basic-instructions.md for PLC soft-element and ladder rules.

Principle

Separate these four things:

Type	Example	Owner
Command request	M100 HMI start request	HMI writes, PLC consumes.
Internal state	M0 motor run latch	PLC owns.
Physical output	Y0 motor contactor	PLC owns.
Display status	M200 motor running display, D200 speed feedback	PLC writes, HMI reads.

Do not let HMI directly own a physical output or a PLC coil that is also driven by normal scan logic.

Address Allocation Template

Range	Purpose	Example
M100~M199	HMI command requests	start, stop, reset, jog.
M200~M299	PLC status to HMI	running, ready, fault, auto/manual.
M300~M399	HMI page/permission/maintenance commands	page request, login state.
M500~M599	Alarm active bits	motor overload, sensor timeout.
D100~D199	HMI numeric setpoints	speed, time, count.
D200~D299	PLC feedback to HMI	actual speed, cycle count, position.
D300~D349	HMI screen/interaction registers	screen command/current screen.
D500~D599	Diagnostics/error codes	communication result, step number.

Adjust ranges to the actual CPU model and project size.

Command / Acknowledge Handshake

Use when HMI requests a one-shot PLC action.

Address	Direction	Purpose
M100	HMI -> PLC	Start request.
M101	PLC -> HMI	Start accepted/ack.
M102	PLC -> HMI	Start rejected/fault reason available.
D500	PLC -> HMI	Reject/error code.

Sequence:

1. HMI sets M100.
2. PLC detects rising edge of M100.
3. PLC checks permissives.
4. If accepted, PLC sets run latch and pulses/sets M101.
5. If rejected, PLC sets M102 and writes D500.
6. HMI or PLC clears M100 after acknowledgement.

For simple buttons, a momentary bit plus PLC edge detection is often enough.

PLC-Controlled HMI Screen

Recommended registers:

Address	Purpose
D300	Screen command register.
D301	Current screen report register.

Rules:

• HMI 交互 -> 控制画面变换 reads D300.
• HMI clears D300 to 0 after jump.
• HMI 报告当前画面号 writes D301.
• PLC writes D300 only on event/edge.

Example:

Event	PLC action
Alarm requires operator attention	MOV K20 D300 to jump to alarm page 20.
Maintenance mode entered	MOV K30 D300 to maintenance page 30.
Current page confirmation	Monitor D301 = K20/K30.

HMI Parameter Write

For operator setpoints:

1. HMI writes raw setpoint to D100.
2. PLC range-checks D100.
3. PLC copies valid value to internal working register D110.
4. PLC rejects invalid value by setting alarm bit and writing reason code.

Pattern:

Address	Purpose
D100	HMI input setpoint.
D101	HMI input minimum or recipe value.
D110	PLC accepted setpoint.
M510	Setpoint invalid alarm.
D510	Invalid reason code.

Do not use HMI-entered values directly for motion/heating/pressure until PLC validates the range.

Alarm Integration

PLC owns alarm truth; HMI displays it.

PLC bit	HMI message
M500	Emergency stop active.
M501	Motor overload.
M502	Sensor timeout.
M503	Communication fault.

HMI reset button should write a request bit such as M120, not clear alarm-active bits directly. PLC clears alarms only after the condition is safe and reset is valid.

Debug Page Template

Include a hidden/maintenance screen with:

• PLC RUN/system status: SM000, fault bits.
• Current screen report: D301.
• HMI communication counters: relevant PSW counters if used.
• Command bits M100~M199.
• Status bits M200~M299.
• Alarm bits M500~M599.
• Key setpoints and feedback registers.

Protect this page with password/permission where needed.

Commissioning Checklist

• Confirm PLC and HMI use the same station/protocol/address notation.
• Test HMI buttons with PLC in safe manual mode.
• Confirm PLC does not OUT to HMI-operated command bits.
• Confirm HMI displays PLC-owned status bits, not only command bits.
• Test invalid setpoint rejection.
• Test alarm trigger, display, acknowledge, reset, and history.
• Test page switching command and current-screen report.
• Save the address table with the project.