Instrument Basic Operations and Factory Reset

1. Panel Description

PV Window: Displays the measured value.

SV Window: Shows the setpoint value.

MV Window: Indicates the output percentage.

Key Functions:

Arc Key: Enters parameter settings and confirms modifications.

Left Key (A/M): Shifts data positions (also used for point control).

Down Key (RUN): Decreases values (also toggles Run/Pause).

Up Key (STOP): Increases values (also stops operations).

Indicator Lights: Display output status for corresponding channels.

2. Modifying the Setpoint (SV)

For Fixed-Value Control:

In normal operation mode, press the Left Key briefly to enter the SV setup interface.

Use the Left, Up, and Down Keys to adjust the SV value.

Troubleshooting:

If unable to modify the SV, set LOC = 0.

For Programmed Instruments:

Enter the parameter menu and set Pn0 to the required number of program segments.

Return to the main display, then press the Left Key to enter program editing mode.

Define values and timing for each segment.

3. Accessing and Modifying Internal Parameters

Parameter Categories:

Field Parameters: Basic settings accessible directly.

Full Parameters: Advanced configurations requiring deeper access.

Steps to Enter Full Parameters:

Press and hold the Arc Key for 2 seconds to open the settings menu.

If only a few parameters are visible, exit and retry.

In the settings menu, locate LOC (if absent, hold the Left Key to display it).

Enter the default password (808) to access full parameters.

Modifying Parameters:

Use Up/Down Keys to adjust values.

Press the Arc Key once to save changes and advance to the next parameter.

Timeout: 25 seconds of inactivity will discard changes and exit.

Immediate Save: Press Left Key + Arc Key simultaneously to save and return.

4. Factory Reset

Single-Loop Instruments (Version V9.2+):

Set LDAL = 995.8, BAUD = 995, and CTRL = APID to restore factory defaults.

Multi-Loop Instruments:

No one-click factory reset function is available.

Key Terms

LOC: Local Control Mode (parameter for access level).

Pn0: Program Segment Count (for programmed instruments).

LDAL/BAUD/CTRL: Critical parameters for system configuration (reset to defaults as specified).

Note: Ensure the instrument is powered on and in the correct mode before performing operations. For complex configurations, refer to the user manual or contact technical support.

To initiate auto-tuning, ensure the control mode (Ctrl) is set to APID or nPID. For single-loop instruments, when the measured value (PV) is stable, set the SV (setpoint) to approximately 60% of the typical operating temperature. Press and hold the Left Key for 2 seconds to access the At parameter, then toggle it from OFF to ON and confirm with the Arc Key. The instrument will display a flashing "At" indicator during the process. Once the flashing stops, reset the SV to the desired temperature to resume normal operation. For multi-loop instruments, activate auto-tuning by setting AtX = 1 (e.g., At2 = 1 for Channel 2); the parameter will revert to 0 automatically after completion.

If auto-tuning fails to initiate on a single-loop instrument, first verify the control mode and enter the full parameter menu (ensuring LOC = 0 for access). Adjust the At parameter from OFF to ON (or FOFF to ON) and confirm LOC = 0 before retrying.

To terminate auto-tuning, press and hold the Left Key for 2 seconds to reset At from ON to OFF on single-loop instruments. For added safety, set At to FOFF to lock the parameter and prevent accidental reactivation. On multi-loop instruments, simply set the corresponding channel’s AtX parameter to 0 (e.g., At2 = 0 for Channel 2). Avoid interrupting the process abruptly to ensure accurate calibration.

Notes:

LOC must be 0 to modify critical parameters like At.

FOFF locks the auto-tuning parameter to prevent unintended activation.

If the instrument displays non numeric codes, you can refer to the code meanings and corresponding methods shown in the picture:

1. 1. Single channel instrument:

Note: If necessary, the flashing display for upper/lower limit and deviation alarms can be disabled to reduce excessive flickering (set the ADIS parameter to OFF).

2.Multi-channel Instrument:

Note: For multi-channel instruments, an out-of-range condition is indicated by the PV flashing while displaying either the maximum or minimum value. In such cases, verify the following:

· Input specification parameters are set correctly.

· Input wiring is properly connected.

· Input signal is functioning normally.

1. Inaccurate Display Resolution:

For minor discrepancies, correct the SCB parameter. Press and hold the circular button to access the menu interface, set LOC to 808, then press the circular button again to locate the SCB setting. For significant errors, verify the integrity of the input signal. In addition to SCB adjustments, advanced instruments may provide multi-point calibration for measurement values.

2. Large PV Measurement Value Fluctuations:

Ensure the sensor input uses a shielded cable; unshielded cables are only permissible for short-distance applications with minimal electromagnetic interference. Validate the sensor’s operational status. Some thermocouples exhibit poor internal insulation, leading to contact between the negative pole and the housing. Unless required for high-speed temperature sensing, avoid such products in multiplexed measurements sharing a common negative pole. High-temperature leakage from furnace insulation materials may induce measurement fluctuations and compromise system safety. If high measurement speed is unnecessary, adjust the instrument’s filter parameters to mitigate data instability when required.

1. Output Signal Settings

The instrument’s output signal is pre-configured based on the factory-installed module type and typically requires no adjustment. Control modes include PID control and ON/OFF control, which can be selected via the Ctrl parameter.

2. Determining Output Functionality

Check Output Status:

· Verify if the OP1 indicator light is illuminated. A lit light indicates normal output.

· Use a multimeter to confirm the signal at the output terminal is normal.

· If the signal is valid but the downstream actuator fails, inspect wiring or peripheral devices for faults.

· Absence of an output signal suggests an issue with the instrument’s output module.

3. Output Behavior When PV Exceeds SV

· Persistent PV > SV:

Improper PID/MPT parameter settings (e.g., reverse action set to positive via CF/ACT parameters, or non-zero OPL lower limit) may trigger output.

· Adjust parameters or perform self-tuning to resolve instability.

· Control Logic Explanation:

Even when PV exceeds SV in heating systems, output may persist due to proportional action reduction and integral/derivative terms accounting for trend and historical data.

4. Addressing Control Instability

New System Setup:

· Perform self-tuning once before deployment to optimize parameters.

·Allow the instrument to run for 10–60 minutes after tuning to stabilize performance.

· For identical systems (e.g., same furnace model), reuse validated PID/MPT parameters to avoid redundant tuning.

Manual parameter adjustments may be required under special conditions.

5. Alarm Output Issues

No Alarm Signal Despite Indicators:

Verify alarm parameter settings, AOP configurations, and ensure the alarm module is properly installed.

6. Excessive Relay Cycling

Mitigation:

· Increase the output cycle parameter (CTI) to 15–60 seconds.

· For longevity, recommend using solid-state relays or thyristors instead of mechanical relays.

The instrument’s program segment mode operates in either Slope Mode (default) or Platform Mode.

Slope Mode: Enable the Measurement Value Preparation Function by setting PAF.H = 1.

Platform Mode: Activate the preparation function by configuring both PAF.A = 1 and PAF.B = 1 simultaneously.

Note: The measurement preparation function requires coordination with the Lower Limit Alarm Bias (LDAL) and Hysteresis (AHYS) parameters. Typically, set LDAL = -3.0 and AHYS = 2.0 to ensure proper functionality.

When the program time is set to a negative value, it activates the jump + event output function. The integer part specifies the target segment number for program jump, while the decimal part defines the event output configuration. Event outputs can be assigned to trigger alarm actions after program execution or segment completion alerts (by setting parameter PAF.E=1, event outputs for AU1 and AU2 can be configured as follows):

XXX.1: AL1 action, AL2 reset;

XXX.2: AL1 reset, AL2 action;

XXX.3: Both AL1 and AL2 actions;

XXX.4: Both AL1 and AL2 resets.

The configuration is divided into two parameter groups: AXX (temperature segmentation values) and dXX (power segmentation values). d00-d59 units are defined as 100% × (1/2000). To activate the settings:

A00 = 1: Fixed value.

A01 = 1050: Fixed value.

A02: Starting temperature for output limitation.

A03: Temperature range for output limitation (highest temperature – lowest temperature).

A04: Segment length for non-linear temperature division (A03/N, where N is the number of segments).

d00: Maximum output power when temperature < A02 (starting temperature).

d01: Maximum output power when temperature < A02 + 1 × A04.

d02: Maximum output power when temperature < A02 + 2 × A04.

d0N: Maximum output power when temperature < A02 + N × A04.

Recommendation: Add a power limit after d0N, setting d0(N+1) = d0N for consistency.

To configure manual output on single-channel instruments with manual/auto control functions, ensure the A-M parameter is set to either MAN (Manual) or Auto mode. In the normal display state, press the circular button to access the manual/auto interface. If the first digit displayed on the SV screen shows "A," the system is in automatic output mode; press the left key to toggle between automatic and manual states. If the first digit displays "M," manual output is active, indicated by the illuminated MAN indicator light, allowing adjustment of the output percentage via the down/up keys. Exit the interface by briefly pressing the circular button. For multi-channel instruments, set the At parameter to 3 (for AI-8xx8 models) or 20 (for AI-7xxx models) to enable manual output, then modify the corresponding channel’s OP parameter to specify the desired manual output percentage.

Notes:

1、Maintains technical terms (A-M, At, OP, SV) for accuracy.

2、Streamlined into a cohesive paragraph for formal, website-appropriate presentation.

YUDIAN meters of version V8.X and above fully support the MODBUS protocol, while for certain V7.X models (e.g., AI-708H), can support MODBUS by installing the S6 module.