Hello all. We have a site with three Mark V <I> hmi's running MS-DOS 6.22. It is a typical 2 on 1 combined cycle plant. Recently, one of the hard drives failed in an <I> computer. We were able to replace it with the hard drive out of a spare <I> machine but that was our last spare. I had to configure the IO_ports.dat file to assign the correct unit's data to the modbus port used to interface with the DCS but other than that I did not have to change anything. Planning to make three backups for the hard drives in the <I>'s I purchased three Maxtor 20GB IDE hard drives. I removed the hard drive from the recently replaced I box and cloned it on to one of the new drives. When I installed the new drive in the <I> box, it recognized the hard drive model number but in the bios the size was shown as 0. The original drive I cloned an image from was an 8.0 GB Fujitsu hard drive. After some research, it appears as if the max hard drive size for MS-DOS 6.22 is 8.0 GB. Is there a work around to this issue or should I just get three more 8.0 GB hard drives? Also, can the software which has all three units be cloned on all three drives and I just change the IO_ports .dat file to assign it to a unit or is there typically Unit specific data that needs to be copied from each drive? Any of the <I> HMI's can control any of the three units currently.

Thanks for your help!

 

For the 8.0GB issue, have you tried to partition the new drive to have separate drives with a max size of 8.0GB? That should solve your problem.
For the cloning of software for all 3 units, I would expect it to work just fine after you change the IO_ports.dat to assign the HMI. That should have everything you need regardless of what unit it is assigned to.