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Need help?Do you have a question about the ITW Simco-Ion ST-4 and is the answer not in the manual?
Equipment is not for hazardous environments or corrosive materials.
Use in ESD-free processes, avoid contamination, dew, and corrosive fumes.
Handle with care, avoid radio noise, do not touch sensor, and battery care.
Inspect equipment upon receipt and report any damage.
List of items included with the ST-4 and optional accessories.
Overview of the Simco Worksurface Tester ST-4 and its purpose.
Explanation of how the ST-4 measures surface resistivity using Ohm's Law.
Technical specifications including range, voltage, accuracy, and dimensions.
Battery charging, indicator, and measurement settings.
Steps for surface resistivity and resistance to ground checks.
How to interpret exponent values less than a decimal point for accuracy.
Visual representation of the physical dimensions of the ST-4 tester.
Method for cleaning the tester probes using isopropyl alcohol and air drying.
Details of Simco's warranty, exclusions, and return procedures.
The Simco Worksurface Tester Model ST-4 is a portable and user-friendly instrument designed for evaluating a wide variety of ESD protective materials. This includes table mats, floor mats, hard laminates, and conductive floors. Its primary function is to measure surface resistivity and resistance to ground, providing crucial data for maintaining electrostatic discharge (ESD) safe environments.
The ST-4 operates by placing a potential difference (V) of either 10V or 100V DC between its parallel conductive probes. It then measures the resulting current (I) to automatically calculate the resistance between the probes using Ohm's Law (R=V/I). This resistance measurement is equivalent to the surface resistivity in ohms per square. The device then displays this resistivity as an exponent on its LCD, after logarithmic conversion, allowing for easy interpretation of results.
A key feature of the ST-4 is its ability to measure both surface resistivity and resistance to ground. For surface resistivity checks, the tester is gently placed on the surface to be tested. Upon pressing the START button, the measurement begins, indicated by a green LED in TEST mode. During this process, the LCD shows "---" (no value) and a bar graph indicates measurement progress. Once the measurement time is complete, a yellow LED lights up, and the resistivity value is displayed as an exponent with one decimal point (e.g., 10^8.4).
For resistance to ground checks, a ground lead is attached to the RESISTANCE TO GROUND jack on the side of the tester. This automatically switches the device to ground check mode, indicated by a red LED in TEST mode. The other end of the ground lead is connected to a common point grounding block or another known nearby ground. Similar to surface resistivity checks, the ST-4 is placed on the surface, and the START button initiates the measurement. The LCD and LED indicators provide feedback on the measurement progress and final value.
The ST-4 incorporates a one-chip micro-processor, enabling precise and wide-range resistivity measurements. It uses low-resistivity rubber-covered probes (10^-2 Ω/cm or below) that are charged with a standard voltage (10V or 100V) through internal protective resistance. The device also includes a timer to prevent it from remaining on unnecessarily, helping to conserve battery life.
The ST-4 is designed for straightforward operation. To begin a measurement, simply turn on the power switch, place the tester on the desired surface, and press the START button. The device automatically adjusts the measurement voltage (10V or 100V) based on the resistance range.
The LCD display provides several useful indicators:
LED indicators provide additional status information:
The measurement time can be configured to 15, 30, or 60 seconds using the SET button and UP/DOWN buttons. Users can also set maximum and minimum resistivity thresholds. If a measurement falls outside these set ranges, the indicator will blink and show either "[+]" (above maximum) or "[-]" (below minimum).
The device features an internal battery and can be charged via a USB port (mini-B-USB) using an AC/DC adapter or a PC's USB port. The red CHARGE LED indicates when charging is in progress. It is important to turn off the switch when the device is not in use and to charge the battery frequently, as the nickel-metal hydride battery can become non-chargeable if left in ON or OFF condition for longer than one year due to discharge.
Proper maintenance ensures the longevity and accuracy of the ST-4. The device is intended for use in electrostatic processes free from water, oil, solvent, and other conductive contaminants. Exposure to such contaminants can damage the electrical insulation system. Special care should be taken to prevent dew formation, and the equipment should be stored or used in a place with less than 60% relative humidity.
The probe's insulated part is made of fluorocarbon polymer, which provides high resistance and prevents dirt accumulation. However, the probe rubber can still accumulate dust, dirt, and oils, which can affect measurement accuracy. If the probe is not clean, the displayed value may be lower than the real value for high resistance objects or higher than the real value for low resistance objects.
To clean the probe, use pure isopropyl alcohol on a lightly moistened swab. After cleaning, allow the probe assembly to air dry completely before using it again. It is crucial to turn off the power switch before cleaning the electrode part to prevent electric shock. If, after cleaning, the equipment still does not function properly, it may indicate mechanical problems, and users should contact Simco Japan Inc. or an authorized agent for assistance.
The ST-4 is a delicate instrument and should be handled with care to avoid damage from dropping. If dropped, it should be examined by an authorized technician for necessary repairs. The device also contains a chip micro-computer, so it should not be used under radio wave noise. Users should avoid touching or harming the sensor and should not weigh on or push the LCD display with their fingers.
The equipment is assembled and inspected at Simco Japan, Inc. Users should not attempt to disassemble or modify its construction. If there are any questions regarding operation or maintenance, contacting Simco Japan's authorized agent is recommended. The device is not suitable for classified (hazardous) environments and should not be exposed to ignitable or corrosive materials and gases. It should also not be operated in an ambient with corrosive fumes of acid/alkali or corrosive gases such as chlorine.
General| Resolution | 10V |
|---|---|
| Display | LCD |
| Power Supply | 9V battery |
| Measurement Range | ±20 kV |
| Response Time | 1 second |
