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Product(s) Affected: Multi-level Supervised Contact Input FIM
Model or Part Number(s): 30-0076-1, -2, -3
Release Date: December 1, 1994
Subject: Current Source Adjustment Procedure
Document No.: 90-0076-005


This procedure describes how to adjust the 30-0076 Multi-level Supervised Input Module current source and scan clock.

Related Documents

If the documents described in this section are available on-line, they will be represented by a hypertext link, which you can click to go immediately to the referenced document.

If they are represented by plain text, then the document is not (yet) available in our on-line library, and must be obtained from SYSTEM SUPPORT SERVICES. Schematic diagrams are proprietary, and will not be available on-line.

1. 90-0076-006 Field Test Procedure, 30-0076
2. 35-0076 Schematic Diagram, Multi-level Supervised Input Module

Equipment Required

Item No. Quantity Description
1. (1) Suitable card cage or other source of regulated power for the board under test
2. (1) 30-0008 FIM extender Card
3. (1) 3 digit digital Multi-meter (Fluke 8024B or equivalent) with appropriate test leads
4. (1) Small flat screwdriver or adjusting tool
5. (1) 30-0076 board to be adjusted
6. (1) Resistance decade box with a 1% or better tolerance (if a decade box is not available, precision 1% resistors of the specified values may be substituted.)
7. (2) Test leads with hook type or mini alligator clips
8. (1) Document # 35-0076 Schematic diagram of the Multi-level Supervised Input Module
9. (1) Frequency Counter capable of measuring period
10. (1) 14 or 16 pin DIP clip (optional)

Current Source Adjustment Setup

  1. Power off the card cage which will be used to power the board under test.
  2. Install the 30-0008 extender card (item 2) into an unused slot in the card cage.
  3. Using the test leads (item 7,) attach one side of the decade box (item 6,) to strap No. 1 or to the "C" pin of transistor Q-2 (current source output.) Attach the other side of the decade box to ground.
  4. Set the decade box to 10.0K ohms.
  5. Plug the board under test into the extender card and power on the card cage. Allow the board to sit with power applied for at least five (5) minutes before attempting any adjustments.

Current Source Adjustment Procedure

  1. Set the meter to a suitable mode and scale to measure 4 volts DC.
  2. Connect the positive lead of the meter to the collector of transistor Q-2 or to strap No. 1 (current source output.) Connect the negative side of the meter to ground.
  3. Verify that the meter reads 4.00 volts 0.06 volts. If the reading is outside this range, then perform the adjustment outlined in step 4. Otherwise, proceed with step 5.
  4. Adjust R-3 until the meter reads 4.00 volts 0.06 volts. If the adjustment cannot be made, then the board is defective and must be repaired.
  5. Set the resistance decade box to 2.50K ohms, and verify that the voltage reading is 1.00 volts 0.015 volts. It may be necessary to adjust the meter scale to achieve the required precision.
  6. Set the resistance decade box for 20.0K ohms, and verify that the voltage reading is 8.00 volts 0.12 volts.
  7. If the end point readings are not within specified limits, repeat steps 4 through 6. If the readings are still not within limits, the board is defective and must be repaired.

Clock Adjustment Setup

  1. Set the frequency counter (item 9) function and range to measure a period of 4 milliseconds.
  2. Connect the frequency counter to Z3 pin 3.

Clock Adjustment Procedure

  1. Verify that the counter is reading 4 milliseconds 5%. It may be necessary to adjust the triggering of the counter to achieve a stable reading.
  2. If the reading is outside this range, adjust R24 until the reading is 4 milliseconds 5%.
  3. When the adjustment is complete, power off the card cage and remove the board.


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