Advance Your Tester’s Abilities – Part 1: Capacitance
What are Advanced Instructions?
Advanced Instructions—previously called Custom Instructions—provide increased flexibility and control over Cirris® CH2. For example:
- Advanced Instructions give full control of the voltage and current used in a test.
- Advanced Instructions allow you to use a wide range of external instruments that expand the capabilities of your CH2 test system.
- Some Advanced Instructions allow the CH2 tester to emulate other test equipment in the marketplace.
These instructions have all the benefits of the standard Easy-Wire™ commands—measured values, custom reporting, import/export, and Easy-Wire editor and test interfaces—but with more precise testing options.
Caution: With the added capability and flexibility of Advanced Instructions comes the increased likelihood of errors in the test setup. We suggest that the person using these instructions be skilled in setting electrical test parameters and have a technical electrical background.
A few basic Advanced Instructions come with the Easy-Wire software, but most are available when you purchase a license file. In order to get the latest Advanced Instructions, you will likely need to install a current version of the Easy-Wire software. Your Cirris sales representative can help you with both upgrading Easy-Wire software and obtaining a license file for Advanced Instructions.
From Custom to Advanced
Advanced Instructions were originally known as Custom Instructions because they were invented to answer the needs of customer-specific test requirements. Cirris recognized the value of these instructions extended to a wider audience. In most cases the instructions give the user extended or finer control over the normal algorithms executed for the measurements that are made. We decided the term “Custom” implied that these instructions service a highly specific set of circumstances. Hence the change from Custom Instructions to Advanced Instructions.
Advanced Instructions in Easy-Wire Running the CH2.
A series of Easy-Wire optional test instructions for the CH2 provides advanced control and extends the application to areas beyond general purpose cable and harness analysis. These functions fall within the capability of the CH2 but extend beyond the scope of the Easy-Wire user interface.
Collections of these advanced instructions are held in categories named by the functions they serve. The category Cirris CH2 contains advanced instructions that use the measurement functions that are exclusive to the onboard systems contained in the CH2.
There are several advanced instruction categories that make use of external instrumentation. These instructions route the test leads of the external instrument to the various terminations in the device-under-test through the CH2 test point switching matrix. There, the advanced instructions control the external instrument in making the desired measurements and pass the results to Easy-Wire. The advanced instruction evaluates each measurement and a pass or fail verdict is rendered. Easy-Wire compiles the measurement result in comprehensive test reports which are archived for reference.
The following tables show examples of Advanced Instructions for precise testing using a CH2. Advanced Instructions are necessary when using 4-wire Kelvin testing or measuring capacitance.
Note: This article is part one in a series of articles showing the benefits of Advanced Instructions. While these features may not apply to your situation, we hope to provide answers in a subsequent article in this series. If you do not find the Advanced Instructions for your situation, we encourage you to reach out to us to discuss your testing needs.
| Category | Cirris CH2 |
|---|---|
| Instruction Name | Compliance Limited 2W Resistance
Compliance Limited 4W Resistance |
| Purpose | Measure load resistance with a user-specified maximum voltage across the load. |
| Parameters | Source test point name
Sink test point name Source Compliance Voltage Source Current Dwell Time NPLC (Number of Power Line Cycles for AC noise filtering Measurement Low Limit in Ohms (Optional) Measurement High Limit in Ohms (Optional) Tare Value in Ohms (Resistance offset) |
| Advantage | Make resistance measurements where the voltage across the resistance will not exceed the Source Compliance Voltage set point.
Specify the maximum current through the resistance to produce less than the Source Compliance Voltage. NPLC filters to remove power line induced noise for greater accuracy. Tare Value offsets interface resistance from the measured value. |
| Category | Cirris CH2 |
|---|---|
| Instruction Name | Forward and Reverse 2W Resistance
Forward and Reverse 4W Resistance |
| Purpose | Measure load resistance in both directions and return the average resistance. |
| Parameters | Source test point name
Sink test point name Source Compliance Voltage Source Current Dwell Time NPLC (Number of Power Line Cycles for AC noise filtering Measurement Low Limit in Ohms (Optional) Measurement High Limit in Ohms (Optional) Tare Value in Ohms (Resistance offset) |
| Advantage | Make resistance measurements where the voltage across the resistance will not exceed the Source Compliance Voltage set point.
Specify the maximum current through the resistance to produce less than the Source Compliance Voltage. Removes thermocouple effect produced by junctions of dissimilar metals. Tare Value offsets interface resistance from the measured value. |
| Category | Cirris CH2 |
|---|---|
| Instruction Name | Measure Capacitance |
| Purpose | Measure the capacitance across two user-specified test points. |
| Parameters | Source test point name
Sink test point name Measurement Low Limit in Farads (Optional) Measurement High Limit in Farads(Optional) Tare Value in Farads (Capacitance offset) |
| Advantage | Measure capacitance across source test point and sink point while all other test points float.
Same as the Capacitance standard instruction but with component-specific tare values instead of global tare value. Tare values specific to the source and sink points to offset interface capacitance. |
| Category | Cirris CH2 |
|---|---|
| Instruction Name | Measure Total Capacitance |
| Purpose | Measure the capacitance from one point to all other points. |
| Parameters | Network test point
Measurement Low Limit in Farads (Optional) Measurement High Limit in Farads(Optional) Tare Value in Farads (Capacitance offset) |
| Advantage | Measure capacitance across specified test points to all other points at ground.
Eliminate parasitic capacitance parallel to the network containing network test points. Tare values specific to the source and sink points to offset interface capacitance. |