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Flowcon. Support. Hardware. Configuration. ISA_Boards. ISA_IRQs

Failed scale readings after moving to a new computer.

After moving the Flowcon board into a new computer, the scale readings may fail to properly display on the batching application main screen.


Most computers come with a COM2 port which is both enabled, and using IRQ3.

The Flowcon board uses IRQ3, but does not use COM2

The problem arises if the ISA motherboard does not leave this IRQ3 alone when the COM2 is not otherwise used.

It happens when the chipset does route or share its interrupts correctly.

If COM2 uses IRQ3 the Flowcon board will conflict.

When running the integrated diagnostic program, the "polling mode" scale test will work correctly but the "interrupt mode" tests will not.

Possible solutions:

1) Disable the port for COM2

The disadvantage of this solution is that you have to re-solve this issue if later you want to add a device that needs a com port; like a remote display, or data to an external machine.

2) Disable the interrupt for the COM2 port.

This is the best solution if you can do it, as remote displays and host data comm do not use an interrupt. Unfortunately, some BIOS's will not allow this option.

3) Reassign the interrupt for the COM2 port.

This is the ideal solution, because it keeps all the function of the COM2 port available for future needs. Again, this may not be allowed in the BIOS.

4) If you are not using the port, reassign it to a different COM assignment.

In choosing an address, do not use COM1 at 3F8; do not use IRQ3. Suggest trying for COM3 [at  3E8] with IRQ4, or the interrupts suggested in BIOS setup.

5) Use a different motherboard (computer).

This solution may be easier and quicker than the next solution.

6) If you are using the port, reassign the port to a different COM number, and modify the Flowcon software.

If your application does use the COM2 port (typically to communicate with some other piece of equipment) and you are unable to reassign the interrupt, you will need Flowcon to modify your application program to communicate with a different port. Reassign the port and send Flowcon a change request listing the new comm port address. (NOT RECOMMENDED)

Other Port Conflicts.
Very infrequently, there is a conflict between the Flowcon board and the printer port.

This manifests itself as a "locked up" batcher, stuck on the opening screen with the time-of-day clock in the upper left-hand corner of the screen frozen.


Reassign the printer port from LPT1 (at address 378, interrupt 7) to LPT2 (at address 278, interrupt 5).
See working with the BIOS (below) .


Working with the BIOS (or CMOS) setup screen:

Get into the computer's CMOS setup screen. You typically do this by pressing the DEL key while the computer is booting.
There should be a section in the CMOS setup menu labeled "chipset configuration" or "integrated peripherals".
The stock address for COM2 is 2F8, and the stock interrupt number is 3. Experiment with the settings for COM2 and see if you can reassign the interrupt number independently while not changing the port address.
Good choices for the interrupt number are 5, 9, 10, and 11.
You want to choose an interrupt that does not conflict with anything else in the computer.
Save the configuration and exit the setup screen.