1
                                                                     EXHIBIT 4.6

                      SECOND AMENDMENT TO CREDIT AGREEMENT


         THIS SECOND AMENDMENT TO CREDIT AGREEMENT, dated as of June 30, 2000
(this "Amendment"), is by and between PERCEPTRON, INC., a Michigan corporation
(the "Borrower"), and BANK ONE, MICHIGAN, a Michigan banking corporation (the
"Bank").

                                    RECITALS

         A. The Borrower and the Bank have entered into the Credit Agreement,
dated May 28, 1999, as amended by the First Amendment to Credit Agreement dated
as of August 24, 1999 (the "Credit Agreement"), pursuant to which the Bank
provides to the Borrower a revolving credit facility, including letters of
credit, in the aggregate principal amount not to exceed $15,000,000.

         B. The Borrower now desires that the Credit Agreement be amended in
order to extend the termination date of the revolving credit facility and modify
certain financial covenants of the Borrower thereunder, and the Bank is willing
to so amend the Credit Agreement on the terms and conditions herein set forth.

         NOW, THEREFORE, in consideration of the premises and of the mutual
agreements herein and in the Credit Agreement contained, the parties hereto
agree as follows:


                    ARTICLE 1. AMENDMENTS TO CREDIT AGREEMENT

         The Credit Agreement hereby is amended as follows:

         1.1 The definition of the term "Revolving Credit Termination Date" in
Article 1 is amended and restated in full as follows:

                  "Revolving Credit Termination Date" means July 31, 2002.

         1.2 Subparagraph "(v)" of Section 6.1 is relabeled as subparagraph
"(vi)", and new subparagraph "(v)" is added to Section 6.1, as follows:

                  (v) As soon as available and in any event not later than the
                  close of each of the Borrower's fiscal years, the Borrower's
                  financial projections for the immediately following fiscal
                  year, in form and detail satisfactory to the Bank.


         1.3 Sections 6.12, 6.13 and 6.14 are amended and restated in full as
follows:

   2


                  6.12 FUNDED DEBT TO EBITDA RATIO. The Borrower will not permit
                  or suffer the ratio of (i) the Funded Debt of the Borrower as
                  of the fiscal year end corresponding to the determination date
                  to (ii) the EBITDA of the Borrower for such fiscal year to
                  exceed (A) 3.00 to 1.00 as of June 30, 2000, (B) 3.25 to 1.00
                  as of June 30, 2001 and (C) 3.00 to 1.00 as of June 30, 2002
                  and as of each subsequent fiscal year end of the Borrower.

                  6.13 EBITDA. The Borrower will not permit its EBITDA to be
                  less than (i) ($4,300,000) for the period from January 1, 1999
                  through the end of its fiscal quarter ending on or about March
                  31, 1999, (ii) ($6,200,000) for the period from January 1,
                  1999 through the end of its fiscal quarter ending on or about
                  June 30, 1999, (iii) $1,500,000 for the period from July 1,
                  1999 through the end of its fiscal quarter ending on or about
                  September 30, 1999, (iv) $2,100,000 for the period from July
                  1, 1999 through the end of its fiscal quarter ending on or
                  about December 31, 1999, (v) $3,000,000 for the period from
                  July 1, 1999 through the end of its fiscal quarter ending on
                  or about March 31, 2000, (vi) $5,500,000 for the period from
                  July 1, 1999 through the end of its fiscal quarter ending on
                  or about June 30, 2000, (vii) $500,000 for the period from
                  July 1, 2000 through the end of its fiscal quarter ending on
                  or about September 30, 2000, (viii) $1,200,000 from the period
                  from July 1, 2000 through the end of its fiscal quarter ending
                  on or about December 31, 2000, (ix) $675,000 for the period
                  from July 1, 2000 through the end of its fiscal quarter ending
                  on or about March 31, 2001, (x) $3,575,000 for the period from
                  July 1, 2000 through the end of its fiscal quarter ending on
                  or about June 30, 2001, (xi) $500,000 for the period from July
                  1, 2001 through the end of its fiscal quarter ending on or
                  about September 30, 2001, (xii) $1,200,000 for the period from
                  July 1, 2001 through the end of its fiscal quarter ending on
                  or about December 31, 2001, (xiii) $675,000 for the period
                  from July 1, 2001 through the end of its fiscal quarter ending
                  on or about March 31, 2002, and (xiv) $3,575,000 for the
                  period from July 1, 2001 through the end of its fiscal quarter
                  ending on or about June 30, 2002.

                  6.14 FIXED CHARGE COVERAGE RATIO. The Borrower will not permit
                  its Fixed Charge Coverage Ratio for the fiscal year ending on
                  or about the determination date to be less than (i) 1.50 to
                  1.00 at June 30, 2000, (ii) 1.10 to 1.00 at June 30, 2001 and
                  (iii) 1.20 to 1.00 at June 30, 2002 and thereafter as of each
                  subsequent fiscal year end of the Borrower.




                                      -2-

                     [SECOND AMENDMENT TO CREDIT AGREEMENT]


   3

                    ARTICLE 2. REPRESENTATIONS AND WARRANTIES

         In order to induce the Bank to enter into this Amendment, the Borrower
represents and warrants that:

         2.1 The execution, delivery and performance by the Borrower of this
Amendment are within its corporate powers, have been duly authorized by all
necessary corporate action and are not in contravention of any law, rule or
regulation, or any judgment, decree, writ, injunction, order or award of any
arbitrator, court or governmental authority, or of the terms of the Borrower's
charter or by-laws, or of any contract or undertaking to which the Borrower is a
party or by which the Borrower or its property is or may be bound or affected.

         2.2 This Amendment is a legal, valid and binding obligation of the
Borrower, enforceable against the Borrower in accordance with its terms.

         2.3 No consent, approval or authorization of or declaration,
registration or filing with any governmental authority or any nongovernmental
person or entity, including without limitation any creditor or stockholder of
the Borrower, is required on the part of the Borrower in connection with the
execution, delivery and performance of this Amendment or the transactions
contemplated hereby or as a condition to the legality, validity or
enforceability of this Amendment.

         2.4 After giving effect to the amendments contained in Article 1 of
this Amendment, the representations and warranties contained in Article 5 of the
Credit Agreement are true on and as of the date hereof with the same force and
effect as if made on and as of the date hereof.

         2.5 No Default or Unmatured Default has occurred and is continuing.


                            ARTICLE 3. MISCELLANEOUS

         3.1 If the Borrower shall fail to perform or observe any term, covenant
or agreement in this Amendment, or any representation or warranty made by the
Borrower in this Amendment shall prove to have been incorrect in any material
respect when made, such occurrence shall be deemed to constitute a Default.

         3.2 All references to the Credit Agreement in any other document,
instrument or certificate referred to in the Credit Agreement or delivered in
connection therewith or pursuant thereto, hereafter shall be deemed references
to the Credit Agreement, as amended hereby.

         3.3 Subject to the amendments herein provided, the Credit Agreement
shall in all respects continue in full force and effect.

         3.4 Capitalized terms used but not defined herein shall have the
respective meanings ascribed thereto in the Credit Agreement.



                                      -3-


                     [SECOND AMENDMENT TO CREDIT AGREEMENT]
   4


         3.5 This Amendment shall be governed by and construed in accordance
with the laws of the State of Michigan.

         3.6 The Borrower agrees to pay the reasonable fees and expenses of
Dickinson Wright PLLC, counsel for the Bank, in connection with the negotiation
and preparation of this Amendment and the documents referred to herein and the
consummation of the transactions contemplated hereby, and in connection with
advising the Bank as to its rights and responsibilities with respect thereto.

         3.7 This Amendment may be executed upon any number of counterparts with
the same effect as if the signatures thereto were upon the same instrument.


         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be
duly executed and delivered as of the day and year first-above written.


                                          PERCEPTRON, INC.


                                          By: John J. Garber

                                               Its: Vice President


                                          BANK ONE, MICHIGAN
                                          (formerly known as NBD Bank)


                                          By: Donna M. Boris

                                               Its: Vice President





                                      -4-


                     [SECOND AMENDMENT TO CREDIT AGREEMENT]