Unitek 6-099-04, Operation And Maintenance Manual

Page: 11 / 88

CHAPTER 1: SYSTEM DESCRIPTION
MICROPULL
®
IV WIRE BOND PULL TESTER
990-180 1-3
with respect to the wire bond is less than 5% for misalignments of up to 5 degrees in either plane. The Zero
Drift is
r
0.3% of full scale during the first 15 minutes and negligible thereafter.
Electronic Control Unit.
The Electronic Control Unit uses a closed-loop servo system to control the vertical position and pull rate
of the Beam Module. The control unit converts the analog information received from the Beam Module
into digital data, displays the peak force, and transmits this data together with any error messages to the
optional RS-232C Interface. This Interface, which is a single board computer, is capable of transmitting
data in ASCII format to a user-supplied buffered serial printer at 1200 baud. The RS-232C interface can
also transmit and receive data, at 1200 baud, to another computer such as an IBM-XT or most other PC
compatibles.
Footswitch
– The footswitch connects into the FOOTSWITCH connector on the rear of the MP4. It is
used by the operator to signal the MP4 to start the next test and, in those cases where the printer or
computer is used, process the data from the previous test. The footswitch also resets the display. If a
customer-supplied switch is used, its contacts should be single pole, normally open, and capable of
switching 125 mA peak current.
Remote Operation - the Beam Drive Module and/or the Electronic Control Unit may be removed from
the baseplate and operated while separated by as much as 6 feet. The Control Lever potentiometer may
also be replaced by a remote potentiometer or by a multiplying digital-to-analog converter. These
modifications might be necessary if the MP4 is made part of an automatic machine and/or is controlled
by an external computer.
Data Outputs – 13-line, 15 volt, positive true, BCD data is applied to the pins of an internal 50-pin
connector. There are additional data lines for the Print Command output, the Computer Busy input, and
MP4-generated Failure Code (table 1-1). The Print Command is held high for 10 milliseconds after the
operator presses the footswitch. The data in the BCD data registers is stable during this period. The
data and error code is then reset to zero and the MP4 performs the next test. An external device cannot
clear the MP4, but can inhibit or enable it by means of the Computer Busy input. The logic levels are 0
and +15 volts for logical 0 and 1, respectively.
Table 1-1. Failure Codes
Code Definition
0 No Test or Test In Process
1 No Failure in Non-Destruct Mode
2 No bond failure prior to reaching the Preset Force or a completed test in the
Destruct Mode
3 Wire bond failure during Hold Time
5 Over-range indication in Non-Destruct Mode
8 Excessive loop height. Beam hit Upstop prior to exerting the Preset Force
9 Marginal loop height. Beam hit Upstop during Hold Time
Data Output Connector, J7
.
The signal and pin numbers on Data Output connector, J7, located on the
logic PCB, are shown in table 1-2. In the table, A is the most significant digit and 8 is the most