Chapter 1 - Introduction

Congratulations! You have just purchased one of the most valuable pieces of test equipment you'll ever own. Today, even simple electronic systems are complex - with sophisticated switching power supplies and IC's performing unbelievably complicated tasks. If not designed just right, these systems can occasionally fail to operate following power up. Do you know if your design will work every time you power it up? Even if it fails only once every thousand times and you only sell a thousand of these systems, every day some customer is going to wonder "What's wrong with my unit?"

Poc-it makes it easy to power-cycle and test your new design before trouble occurs downstream, in manufacturing or even in the field. Poc-it can also be used in the manufacturing cycle to power-cycle and test a product during burn-in. Because of its compact size and limited number of connections, power-up problems can be detected with Poc-it on a system being tested in a burn-in chamber.

The philosophy behind Poc-it is quite simple. Most modern electronic equipment has some kind of power-up test or initialization sequence. Sometimes, a system will fail to initialize or pass the power-up test for a variety of reasons. If the unit contains software, a subtle race condition or uninitialized hardware port can cause the unit to intermittently fail to start-up properly. The hardware may also have a subtle race condition or be using a part that is being stressed beyond its design specification. In addition, most systems have some output that can be used to indicate when initialization is complete. For example, a system that incorporates a printer with a parallel port will strobe the printer initialization line at startup. If such an output is not available, during the design phase, one output can be designated for this purpose. Poc-it can be configured to cycle power to the system under test and count the number of transitions of this output.

At MicroTools, we have a philosophy that says "If it's not tested, it doesn't work." We have found this to be true more often than we care to admit. Poc-it provides a simple way for you to verify that a design or a product will work day after day without a glitch.

Chapter 2 - How to Set-up Poc-it

What Poc-it Controls

To provide maximum flexibility in a small package, Poc-it provides two outputs to control power cycling. The first is a ten amp AC output which is available in a standard three prong outlet on the back panel. The second is a five amp relay contact (8 amps non-inductive). DC or AC can be switched by feeding the power into the Relay In banana jack and taking the switched power out of the Relay Out banana jack.

What Poc-it Monitors

One high speed 5 volt input (Input #2) and one opto-isolated 10-30 VDC input (Input #3) are provided. The minimum detectable pulse width on the high speed input is 2 microseconds. The minimum detectable pulse width on the opto-isolated input must be greater than 1 millisecond. Each input can be used independently during power cycling. Input pulses that occur more frequently than every 1 millisecond will not be counted. Input #1 is reserved for Remote Turn-on.

What Needs to be Setup?

Poc-it allows you to select from two timing modes (Vary Time and Fixed Time), from two failure modes (Pause on Failure or Count Failures) and two modes of turn-on (from the keyboard or remotely from a PC).

Timing Mode - Poc-it provides two timing modes. In the Fixed Timing Mode, the On and the Off times are programmable. The Vary Time mode allows you to randomize the power cycling. When set to Vary Time, Poc-it will vary the On and the Off times within the limits entered. In this mode, timing is set by setting a Min and a Max On Time and a Min and a Max Off Time. Varying on and off times can greatly increase the chances of finding power related problems that occur only in a specific time window. Even with the Max and the Min times identical, the Phase Angle at turn-on will be random.

Remote Mode - The Remote parameter can be set to On or Off. When set to Off, the starting and stopping of the test are controlled from Poc-it's keyboard. When set to On, the starting and stopping are controlled via a serial connection with a PC. This is an add-on option for Poc-it. If you did not purchase this option, it can be purchased for $100 by calling 1-800-651-6170.

Failure Mode - Using the On Failure Pause/On Failure Count parameter, Poc-it allows you to perform one of two actions when a failure occurs: Either Pause the test (i.e., stop testing but keep the outputs on) or keep running the test and count the number of failures.

In addition, the various parameters for these modes need to be set up including the On and Off times (with maximum and minimum ranges), the Input Delay, and the Failure Conditions.

On Time - This parameter defines how long the AC output will remain On and the relay will remain closed for each cycle. When in Vary Time mode, both a Min & Max On Time can be set. The Max Time will not be allowed to go below the Min Time. If the Min Time is increased above the Max Time, the Max Time will be set to the same value as the Min Time once the test is started. The algorithm that varies the time is pseudo random and can cover all cycle times including the Min and the Max with the 10 msec resolution. The approximate number of cycles to cover each 10 msec value in the range is 15 times the number of possible values. Note: In all modes, the AC output is not turned off until zero crossing. This will affect the On and Off times by at most 8.3 milliseconds.

Off Time - This parameter defines how long the AC output will remain Off and the relay will remain closed for each cycle. When in Vary Time mode both a Min and a Max Off Time can be set. The Max Time will not be allowed to go below the Min Time. If the Min Time is increased above the Max Time, the Max Time will be set to the same value as the Min Time. The algorithm is the same as used for the On Time.

Input Delay - This parameter defines how long after the On Time starts before the inputs are considered valid to start sampling. This value provides a hold off period for the system under test to stabilize and complete initialization. The inputs are sampled at the end of the delay time to define the "initial value." Any Transitions to the opposite value during the remaining On Time are counted in the input counters. If the input is high at the end of the Input Delay, then falling edges will be counted. Likewise, if the input is low at the end of the Input Delay, then rising edges will be counted. A delay time of zero means that the "initial value" will be sampled and defined at the time the outputs are turned on.

Threshold - This parameter is used only as a part of the "Pause If, At End" conditions that compare the "Input Counter" (IN CNT) to the Threshold (TH). The value may be set with a 0 - 99. This parameter is used to set the threshold of the valid transitions following a power turn on. The default is 0.

Fail If, At End - This parameter defines under what condition the testing should be failed. One of ten conditions may be selected to define a failure condition of the Unit Under Test. If the condition is met at the end of the On Time, Poc-it will go into either a paused state or keep running (based on the On Failure Pause/Count) menu parameter. The On Time, Off Time and counters may be read to see what conditions caused the testing to suspend. The fail conditions are sampled at the end of the On Time before the start of the Off Time. The possible conditions are:

In X Never - The default - prevents any failure events.

In 2 On - Fail test at the end of the on cycle if Input 2 is high.

In 2 Off - Fail test at the end of the on cycle if Input 2 is low.

In 2 Cnt > Th - Fail test at the end of the on cycle if the count for Input 2 is greater than the Threshold.

In 2 Cnt < Th - Fail test at the end of the on cycle if the count for Input 2 is less than the Threshold.

In 3 On - Fail test at the end of the on cycle if Input 3 is high.

In 3 Off - Fail test at the end of the on cycle if Input 3 is low.

In 3 Cnt > Th - Fail test at the end of the on cycle if the cnt for Input 3 is greater than the Threshold.

In 3 Cnt < Th - Fail test at the end of the on cycle if the cnt for Input 3 is less than the Threshold.

In X Always - Fail test at the end of the first on cycle.

All time parameters have a range from 0 ms to 99 min 59.99 sec in 10 millisecond increments. The default value is 0 for each.

What Results can be Monitored

Both during testing and at the completion of a test, the following parameters can be monitored:

Variable On/Off Times- When the timing mode is set to Vary Time, the On and Off time at which the failure occurred can be monitored.

Cycle Counters - The total number of power-on cycles performed can be monitored.

Input Counters - The number of transitions of Inputs #2 and #3 can be monitored dynamically and after a failure (In x Cnt). In addition, Input #3 can be used to maintain a total count when the system is in the On Failure Pause mode (Totl In 3 xxxxxx).

The maximum number of counts is 999,999 for Cycles, Input 3 Total Counter and Failures. Above this number, the counters roll over. The maximum number of counts for Input counters 2 (In 2) and 3 (In 3) is 99. Above this, the counters remain at 99. These counters are cleared at the start of each cycle.

What Control Operations can be Performed

The user can start, stop, pause and continue the test. (With the Remote Turn-on Option, the user can start and stop from their PC). Starting the test sets all counters to zero. Stopping the test turns the AC Power off and opens the relay. Counters are not cleared. All counters are updated in real time.

Pause suspends operation in the current state. Continue resumes operation from the current state if Poc-it was Paused. If Continue is selected while it was stopped, Poc-it will perform a start without clearing the counters.

The Menu Tree

The following defines Poc-it's menu tree when the timing mode is set to Fixed Timing:

Upper Level	Lower Level
(C)1996 MTI V2.1
Set Phase Shift	Set Vary Time*
Remote: On	Remote:Off*
On Time	MM:SS xx:xx.xx
Phase Shift	% xx
Off Time	MM:SS xx:xx.xx
Input Delay	MM:SS xx:xx.xx
On Failure Pause	On Failure Count*
Threshold	Th Cnt xx
Fail If, At End
	In X Never
	In 2 On
	In 2 Off
	In 2 Cnt > Th
	In 2 Cnt < Th
	In 3 On
	In 3 Off
	In 3 Cnt > Th
	In 3 Cnt < Th
	In X Always
Start Test	Stop Test*
Pause Test	Continue Test*
Cycles xxxxxx // Number of cycles run
Phase Shift xx //Current Phase Shift
In 2 Cnt xx
Totl In 3 xxxxxx or Failures xxxxxx (in On Failure Count mode)
In 3 Cnt xx

The following defines Poc-it's menu tree when the timing mode is set to Vary Time:

Upper Level	Lower Level
(C)1996 MTI V2.1
Set Vary Time	Set Phase Shift*
Remote: On	Remote:Off*
On Time Min	MM:SS xx:xx.xx
On Time Max	MM:SS xx:xx.xx
Off Time Min	MM:SS xx:xx.xx
Off Time Max	MM:SS xx:xx.xx
Input Delay	MM:SS xx:xx.xx
On Failure Pause	On Failure Count*
Threshold	Th Cnt xx
Fail If, At End
	In X Never
	In 2 On
	In 2 Off
	In 2 Cnt > Th
	In 2 Cnt < Th
	In 3 On
	In 3 Off
	In 3 Cnt > Th
	In 3 Cnt < Th
	In X Always
Start Test	Stop Test*
Pause Test	Continue Test*
Cycles xxxxxx // Number of cycles run
Phase Shift xx
In 2 Cnt xx
Totl In 3 xxxxxx or Failures xxxxxx (in On Failure Count mode)
In 3 Cnt xx

* Not truly a lower level

The Push Buttons

There are four push buttons available for configuring, monitoring and controlling Poc-it.

Next/+ This push button serves two purposes. While navigating the menu, pushing this button will cause Poc-it to display the next menu item on the same level of the menu tree. When configuring Poc-it, pushing this button will increment the blinking digit pair by one. Holding this button down, will cause the digit to automatically increment.

Prev/- This push button serves two purposes. While navigating the menu, pushing this button will cause Poc-it to display the previous menu item on the same level of the menu tree. When configuring Poc-it, pushing this button will decrement the blinking digit pair by one. Holding this button down, will cause the digit to automatically decrement.

Select This push button serves three purposes. While navigating the menus, pushing this button will cause Poc-it to select the displayed menu item. If this menu item is a control operation (Start or Stop the test), the operation will be performed. If the menu item has additional menu items below it in the menu tree, Poc-it will display the next level of menu tree. When configuring Poc-it, the Select push button causes the next digit pair to blink (indicating that it can be changed using the + or - push buttons).

Exit This push button will cause Poc-it to exit a lower menu level and display the entry in the upper menu level.

Navigating through the Menus

The Poc-it menu tree is easily navigated using the four push buttons. The menu tree is transversed on the same level using the Next and Previous buttons. Lower level menus are accessed with the Select button. When a lower level menu is selected, higher level menus are accessed by pushing the Exit button.

Changing Settings/Viewing Results

All configuration settings can be set by selecting the proper digit pair using the Select push button and then using the + and - to increment or decrement the value. From the top level menu, the values of the counters can be viewed.

Chapter 3 - Test Examples

AC Power Cycle Testing

Imagine that your system used AC power (less than 10 amps). It's power-up diagnostic takes 3 seconds. Outputs are valid within 1 second after AC application. If the diagnostic fails, a message is displayed and an acknowledge is required by the user. If the diagnostic passes, the printer port will be initialized. The AC power cord can be plugged directly into the Poc-it AC output. In this case, we will use the Vary Time Option. The On Time Max can be set to 6 seconds and the On Time Min set to 4 seconds. The Off Time Max can be set to 2 seconds and the Off Time Min to 1 second. The printer port Init line can be connected to the high speed input #2. The Input Delay can be set to 1 second.

We will set the Failure Mode to On Failure Count. The Failure Condition will be set to Fail If at End - In 2 Cnt < 1 (we also set the threshold to 1). Start the test. After one hour, Poc-it will have cycled power ~600 times (Cycles). The Failure counter should read 0.

Alternatively, we could stop on the first failure. In this case, we would set the Failure Mode to On Failure Pause. If you were interested, on a failure you could read the On and Off times at which the failure occurred.

DC Power Cycle Testing

Imagine that your board is powered by 5 VDC (less than 5 amps). Your hardware initialization circuitry is complex. Upon successful completion (typically 40 microseconds after power up), a 5 volt signal is set. In this setup, a 5 VDC input is connected to Relay In and a switched 5 VDC output is connected from the Relay Out to your board. The 5 volt output from your board is connected to Input #2. We configure the timing mode to Vary Time. The On Time Max and Min are programmed for 50 milliseconds and the Off Time Max and Min are programmed for 50 milliseconds. The Failure Mode is set to On Failure Count. The Input Delay Time is set for zero. After one hour of testing, Poc-it will have cycled power to the board 36,000 times. The Cycle Counter should also read 36,000 and the Failure counter should read 0.

To stop on a failure, select:

Power Supply Testing

A switching power supply may not come up under all phases of AC turn on if incorrectly designed. The supply also may have trouble with very short power outages. We will assume the power supply takes 40 msec to come up fully and give a good output. To test such a design with Poc-it, use the Vary Time mode and set the On Time to cover a range from .50 to 1.00 seconds and the Off Time to cover the range 0.01 to 1.00. Since we want to identify as much information as possible about the failure case if it occurs, set the "Pause If, At End" condition to "In 2 Off"and connect the output of the power supply to input # 2. (If the power supply output is greater than 5v input # 3 should be used.) Start the test and allow the test to run for one hour. It should execute approximately 2800 cycles of testing, using the above On and Off times. If a problem is found during testing, the On Time & Off Time can be looked at to determine what values may be problematic for the design. The Cycles menu will tell the number of cycles completed.

Processor Reset Testing

Any system with a processor may have a problem when power off conditions are short. If a power supply sees a brown out condition or a short power off condition, the voltage to the processor and other complex logic components can drop partially without going fully to ground. For many systems this condition will give the processor or other complex logic components problems since the level needed to maintain operation was not present and the level to trigger a reset was also not reached.

To test this condition, connect Input # 2 to some logic level output on the processor that is active when the processor is running. This could be an address line, data bus line or some other changing output. Set the On Time Min to 2.00 and the On Time Max to 4.00. Set the Off Time Min to 0.01 & the Off Time Max to 2.00. The Off Time Max should be several times longer than the hold up time of the power supply's capacitors. Set the threshold count value for 10 or an appropriate value that represents the number of times the signal should change for a normal operating system in 2 seconds. Caution: Input #2 can see a signal change of 2 usec wide but is only checked every 1/msec. Thus, a high speed bus may not run up as many counts as expected. Set the "Pause If, At End" to "In 2 Cnt < Th." Start the test. After an hour the system should have completed around 900 cycles. If a problem is found during testing the On and Off Times can be looked at to determine what values may be problematic for the design. The Cycles menu will tell the number of cycles completed.

Chapter 4 - Poc-it Specification

Although the AC output is rated at 10 amps, in order to minimize an internal temperature rise, the following table represents the maximum AC On/Off duty cycle:

Larger duty cycles and longer on times could be maintained by providing external cooling to Poc-it.

Chapter 5 - Warranty and Technical Support

MicroTools will guarantee Poc-it against all defects of material or workmanship which develop for any reason whatsoever, except abuse, within a period of one (1) year from the date of purchase by the original buyer. This warranty is extended only to the original buyer or original user who must present proof of purchase at the time of warranty service

In the USA, any unit claimed to be defective during the warranty period should be returned to:

MicroTools Inc.

PO Box 624

714 Hopmeadow St. Suite 14

Simsbury CT 06070

For technical support, please call 1-860-651-6170.