Mastech MS7220 - User Manual

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Summary

Introduction to Thermocouple Calibrator

Device Safety Information

Safety Precautions

Essential safety warnings to prevent electric shock, injury, and equipment damage during operation.

Operation: Measuring a Thermocouple

Operation: Simulating a Thermocouple

Technical Specifications

Temperature Measure and Thermocouple Simulate Specifications

Details on resolution, error, and reference junction error for temperature measurement and thermocouple simulation.

Millivolt Measure and Source Specifications

Details on range, resolution, and accuracy for millivolt measurement and source functions.

Device Maintenance

Cleaning Instructions

Guidance on cleaning the calibrator case using a damp cloth and detergent.

Calibration Procedure

Recommendation to calibrate the calibrator annually to ensure performance according to specifications.

Battery and Fuse Replacement

Information on replacing the battery when indicated and troubleshooting fuse issues.

The Thermocouple Calibrator is a versatile and precise instrument designed for both sourcing and measuring in thermocouple applications. It serves as an essential tool for calibrating thermocouple instruments, offering the flexibility to operate in units of degrees Celsius (°C), degrees Fahrenheit (°F), or millivolts (mV) through a standard thermocouple minijack. This broad range of measurement and sourcing capabilities makes it suitable for a wide array of industrial and laboratory settings where accurate temperature and voltage calibration is critical.

Function Description

The primary function of the Thermocouple Calibrator is to provide a reliable means of calibrating thermocouple instruments. This involves two main modes of operation: measuring a thermocouple and simulating a thermocouple.

In the Measuring a Thermocouple mode, the calibrator acts as a high-precision thermometer, reading the temperature or millivolt output from an attached thermocouple. Users can select the desired thermocouple type (J, K, T, E, R, S, B, N) and view the measurement in either °C or °F. The device displays the input value and the selected thermocouple type, allowing for direct and accurate temperature readings. The input is connected via a thermocouple minijack, ensuring compatibility with standard thermocouple wires and plugs. This mode is crucial for verifying the accuracy of existing thermocouples or for taking precise temperature measurements in various processes.

In the Simulating a Thermocouple mode, the calibrator functions as a signal generator, outputting a specific temperature or millivolt value to an external device. This allows users to test the response of thermocouple-based instruments by feeding them a known, precise signal. Similar to the measurement mode, users can select the thermocouple type and the desired output unit (°C, °F, or mV). The calibrator provides controls to step up or down the output value in increments of 10° or 1mV, and fine-tune it with 0.1° or 0.01mV resolution. Holding down the scroll buttons enables faster adjustment of the output. This simulation capability is invaluable for troubleshooting, calibrating, and verifying the performance of temperature controllers, data loggers, and other instruments that rely on thermocouple inputs.

The calibrator supports a comprehensive range of thermocouple types, including J, K, T, E, R, S, B, and N. For each type, it adheres to the NIST 175 standard and the ITS-90 scale, ensuring accuracy and traceability to international standards. The ability to measure and source millivolts directly means that the calibrator can be used with any thermocouple type, even those not explicitly listed, by performing manual calculations or referring to external tables. This flexibility enhances its utility across diverse applications.

Usage Features

The Thermocouple Calibrator is designed with user-friendliness and safety in mind, incorporating several features that streamline its operation and ensure reliable performance.

Intuitive Interface: The device features a clear digital display that shows the current input or output value, the selected thermocouple type, and the unit of measurement (°C, °F, or mV). Dedicated buttons for "INPUT" and "OUTPUT" modes, "TC TYPE," and "°C/°F" allow for quick and easy selection of operating parameters. Up and down arrow buttons facilitate precise adjustment of values during simulation.
Thermocouple Type Selection: Users can easily cycle through the supported thermocouple types (J, K, T, E, R, S, B, N) to match the specific application. This ensures that measurements and simulations are performed with the correct linearization curves.
Unit Toggle: A dedicated button allows users to toggle between °C and °F, providing flexibility for different regional standards and user preferences.
Millivolt Mode: Beyond temperature, the calibrator offers a millivolt mode, enabling direct measurement and sourcing of mV signals. This is particularly useful for working with raw thermocouple voltages or for calibrating devices that accept mV inputs.
Resolution Control: In simulation mode, users can adjust the output in coarse (10° or 1mV) or fine (0.1° or 0.01mV) increments, allowing for precise control over the simulated signal. Holding down the scroll buttons accelerates the adjustment process.
Minijack Connection: The calibrator utilizes a standard thermocouple minijack for connecting thermocouple wires and plugs, ensuring broad compatibility with existing equipment.
Portability: The compact and lightweight design of the calibrator, powered by a single 9V battery, makes it highly portable and suitable for field use.
Safety Warnings: The device includes clear safety guidelines to prevent electric shock and personal injury. These include warnings against applying excessive voltage, ensuring the battery door is closed and latched, removing miniplugs before opening the battery door, and not operating the calibrator if damaged or in hazardous environments (explosive gas, vapor, or dust).
International Symbols: The calibrator and its documentation use international symbols (e.g., Earth ground, CE for European Union directives, and a warning triangle for important manual information) to ensure clear communication across different regions.

Maintenance Features

Proper maintenance is essential for ensuring the long-term accuracy and reliability of the Thermocouple Calibrator. The manual provides clear instructions for routine care and troubleshooting.

Cleaning: The calibrator's case can be periodically wiped with a damp cloth and mild detergent. It is important to avoid using abrasive cleaners or solvents, as these could damage the device's finish or internal components.
Calibration: To maintain its specified accuracy, the calibrator should be calibrated once a year. This regular calibration ensures that the device continues to perform within its stated specifications, which is crucial for applications requiring high precision.
Battery Replacement: The calibrator is powered by a single 9V alkaline battery (ANSI/NEDA 1604A or IEC 6LR61). A battery symbol on the display indicates when the battery needs to be replaced. This visual cue helps users avoid unexpected power loss during critical operations.
Fuse Replacement: If the calibrator consistently reads "OL" (Overload) in input mode, even with a thermocouple connected, it suggests that the fuse may be blown. While the manual indicates this possibility, it implies that fuse replacement might be a user-serviceable task or require professional attention, depending on the device's design.
Repair and Service: In the event that the calibrator requires repair, users are instructed to contact the service center. Information regarding warranty terms, fixed-fee repairs for out-of-warranty devices, and pricing is available through the service center. When servicing the calibrator, only specified replacement parts should be used to ensure proper function and safety.

Overall, the Thermocouple Calibrator is a robust and user-friendly instrument designed to meet the demanding requirements of thermocouple calibration and measurement, supported by clear operational guidelines and straightforward maintenance procedures.

Mastech MS7220 Specifications

General

Model	MS7220
Category	Test Equipment
Type	Digital Multimeter
Display	LCD
Max Display	1999
Diode Test	Yes
Continuity Test	Yes
Battery Type	9V Battery
DC Voltage Range	200mV/2V/20V/200V/600V
AC Voltage Range	2V/20V/200V/600V
DC Current Range	200µA - 10A
Resistance Range	200Ω - 20MΩ
Resolution	0.1
Sampling Rate	2.5 times/sec