FIELD TECHNICAL BULLETIN # 4

SCOPE

BACKGROUND

A problem has been discovered in Revision A and earlier 30-0121 Multi-level Supervised Input Modules. This problem manifests itself as an "out-of-sequence" condition when the board is polled by the COMTROL 1 host or Megaplex processor. The problem exists in all versions of the board.

When a change-of-state occurs on the 30-0121 Multi-level Supervised Input Module, the first of two or three data words are presented on the FIM bus. When the host or Megaplex processor polls the FIM, the data word is obtained. The host then performs a "DAACK" command which causes the FIM to present the next data word onto the FIM bus. If the FIM has a two-word data format, DAACKing the channel again causes the FIM to reset that channel. If the FIM has a three-word data format, the DAACK command causes the third data word to appear on the FIM bus. After all data words have been read by the host, a final DAACK resets the channel.

The problem occurs when a new change-of-state occurs before the host has obtained the last data word and reset the channel. It is possible for this new change-of-state to be processed before the old one is completed.

This problem manifests itself in two ways. If a new change-of-state occurs after the FIM has presented the final data word onto the bus, but before the host has read it, the first word of the new change-of-state will overwrite the final word of the previous change-of-state, and data will be lost. An example of this symptom using a FIM with a three-word data format is shown below:

The second manifestation of this problem is when the new change-of-state occurs after the host has read the third data word, but before it DAACKs the channel to clear it. In this case, the DAACK increments to the second data word before the host has read it, and the first word of data is lost. The sequence is as follows:

This problem exists in all versions of the 30-0121 firmware up to and including Revision A.

SOLUTION

COMPUTROL has released a new version of the firmware which corrects this problem. The firmware revision for all versions of the 30-0121 should be Revision A1 or later.*

RECOMMENDATIONS

It is recommended that all boards be upgraded with the new firmware as soon as practical. There are three alternative approaches to implementing the Revision A1 firmware update:

• The modules can be sent to SYSTEM SUPPORT SERVICES for retrofit. The cost to update the firmware and fully test, align, and repair the unit as necessary is $ 359.00 per board.

• EPROMs can be purchased from SYSTEM SUPPORT SERVICES to perform the rework. The price of a parts kit to update one board is $ 49.00, and includes all documentation necessary to install and test the update.

• A site license may be purchased for $ 1,900.00. The site license includes 3 copies of the EPROM to use as masters, all necessary documentation to install and test the update, and a limited use license which permits the site to make unlimited copies of the firmware for its own internal use.

ORDERING INFORMATION

To have SYSTEM SUPPORT SERVICES repair, test and update the modules as necessary, contact Customer Service for a Return Material Authorization number. Have available the part number of the module to be repaired and upgraded, and the quantity.

To order individual copies of the firmware, or to order a site license, please use the following part numbers:

1. When installing P/N 80-2200B firmware on a 30-0121-2 FIM, resistor R19 must be changed from a 2.49K, 1/4 W, 1% resistor to a 1.27K, 1/4 W, 1% resistor. This is because P/N 80-2200B firmware also corrects another problem with the 30-0121-2 version of the FIM (see FTB # 6: 30-0121-2 Firmware Rev. A1 and Hardware Rev. C1.)
   
2. This document is a reprint of an original COMPUTROL Field Technical Bulletin. There is a new revision level for this firmware, which was released by SYSTEM SUPPORT SERVICES. Please refer to FTB # 11, 30-0121-2 Firmware Rev. C and Part Number Change.

 E-mail: service@sysupport.com

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TEL: (727) 379-0484

FAX: (727) 379-0831

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