Mastech MS7221 Volt/mA Voltage Current Calibrator Instruction Manual

1. Introduction

The Mastech MS7221 Volt/mA Calibrator is a precision instrument designed for sourcing and measuring DC voltage and current signals. This device is essential for testing, calibrating, and troubleshooting industrial process control systems, PLCs, and transmitters. It offers high accuracy for both measurement and output functions, making it a versatile tool for professionals in various fields.

2. Safety Information

• Read this manual thoroughly before operating the device.
• Always observe local and national safety codes and regulations.
• Do not operate the calibrator if it appears damaged or is not functioning properly.
• Ensure proper connection of test leads to avoid electrical shock or damage to the device.
• Do not exceed the maximum input ratings specified in this manual.
• The calibrator cannot be used for measurement and source simultaneously.

3. Product Overview

The Mastech MS7221 features a clear display, intuitive controls, and robust input/output terminals. Familiarize yourself with the components shown below.

Figure 1: Mastech MS7221 Front Panel. This image displays the front of the Mastech MS7221 Volt/mA Calibrator. Key features visible include the large digital display at the top, showing "OUTPUT 0.000 V". Below the display are the power button (circular, labeled with a circle and vertical line), and two function selection buttons: "V/mV" (yellow) and "mA/%" (yellow). Further down, there's an "INPUT/OUTPUT" button and four arrow buttons for navigation and value adjustment. At the bottom, various input and output terminals are visible: "+LOOP", "mA INPUT", "COM", and "V INPUT/OUTPUT". Each terminal is clearly labeled with its function and maximum voltage/current ratings.

3.1. Controls and Display

• Display: 24000 counts, shows measured or sourced values.
• Power Button (①): Turns the device on/off.
• V/mV Button: Selects voltage measurement or source mode.
• mA/% Button: Selects current measurement or source mode.
• INPUT/OUTPUT Button: Toggles between input (measurement) and output (source) functions.
• Arrow Buttons (▲, ▼): Adjust output values or navigate menus.

3.2. Input/Output Terminals

• +LOOP: 24V loop supply output.
• mA INPUT: Current measurement input (Max 30V).
• COM: Common terminal for all measurements and sources.
• V INPUT/OUTPUT: Voltage measurement input and voltage source output (Max 30V).

4. Setup

4.1. Battery Installation

1. Ensure the calibrator is powered off.
2. Locate the battery compartment on the rear of the device.
3. Open the compartment and insert the required batteries, observing correct polarity.
4. Close the battery compartment securely.

4.2. Initial Power On

Press the Power button (①) to turn on the device. The display will illuminate and show the default operating mode.

5. Operating Instructions

The MS7221 can either measure or source signals, but not simultaneously.

5.1. Measuring DC Voltage (0-10V)

1. Connect the test leads to the V INPUT/OUTPUT and COM terminals.
2. Press the V/mV button to select voltage mode.
3. Press the INPUT/OUTPUT button to ensure "INPUT" mode is selected.
4. Connect the test leads to the voltage source to be measured.
5. Read the voltage value on the display.

5.2. Sourcing DC Voltage (0-10V)

1. Connect the test leads to the V INPUT/OUTPUT and COM terminals.
2. Press the V/mV button to select voltage mode.
3. Press the INPUT/OUTPUT button to ensure "OUTPUT" mode is selected.
4. Use the Arrow Buttons (▲, ▼) to adjust the desired output voltage.
5. Connect the test leads to the device requiring the voltage input.

5.3. Measuring DC Current (0-24mA)

1. Connect the test leads to the mA INPUT and COM terminals.
2. Press the mA/% button to select current mode.
3. Press the INPUT/OUTPUT button to ensure "INPUT" mode is selected.
4. Connect the calibrator in series with the circuit where current is to be measured.
5. Read the current value on the display.

5.4. Sourcing DC Current (0-24mA)

1. Connect the test leads to the mA INPUT and COM terminals.
2. Press the mA/% button to select current mode.
3. Press the INPUT/OUTPUT button to ensure "OUTPUT" mode is selected.
4. Use the Arrow Buttons (▲, ▼) to adjust the desired output current.
5. Connect the test leads to the device requiring the current input.

5.5. 24V Loop Supply with Current Measurement

1. Connect the +LOOP terminal to the positive input of the device under test.
2. Connect the negative input of the device under test to the mA INPUT terminal.
3. Connect the COM terminal to the common ground of the system.
4. Press the mA/% button to select current mode.
5. Press the INPUT/OUTPUT button to ensure "INPUT" mode is selected.
6. The display will show the current flowing through the loop.

6. Maintenance

6.1. Cleaning

Wipe the device with a damp cloth and mild detergent. Do not use abrasive cleaners or solvents. Ensure the device is powered off and disconnected from all circuits before cleaning.

6.2. Storage

Store the calibrator in a cool, dry place, away from direct sunlight and extreme temperatures. If storing for extended periods, remove the batteries to prevent leakage.

6.3. Battery Replacement

When the low battery indicator appears on the display, replace the batteries as described in Section 4.1. Use only the specified battery type.

7. Troubleshooting

8. Specifications

9. Warranty and Support

Mastech products are designed for reliability and performance. For warranty information, technical support, or service inquiries, please refer to the contact information provided with your purchase or visit the official Mastech website. Keep your proof of purchase for warranty claims.