Question: I have multiple C1900's existing in our plant and we interchange boards when problems occur. I want to buy some new units for spare parts, but I was told that the Commander 1900 has newly designed boards. Are the old and new C1900's compatible?
Answer: The new Commander 1900 has been designed to be backwards compatible to your existing equipment, but there are limitations.
See photos below for comparison purposes
I/O Boards and Processor Boards:
- Original design I/O (C1900-0255) will work with the new processor board (C1900-0425)
- New design I/O (C1900-0405) will work with the original processor (C1900-0265) ONLY if the processor has the updated 12MHz clock*, and C1900-2101 ISS. 7** or later MUST be installed.
- New design I/O (C1900-0405) will work with the second generation processor (C1900-0365) as long as C1900-2101 ISS.7 or later is installed.
Processor Boards and Software Keys:
- Software Keys are NOT interchangeable. The structure and connectors are completely different.
- Display boards (1900-0275/0276) have not been updated, so no compatibility issues exist.
* If your existing firmware (IC23) is C1900/2101, then you have a 12Mhz processor board. If you have a C1900/2001, then the only sure way to verify system speed is to find the Crystal located next to the processor chip (XTAL2). The speed should be stamped on the side of the crystal. A Secondary method is to examine the part number of the processor (IC20) itself. If the part number ends in a 3 (MC68HC11D0CFN3), you more than likely have a 12MHz processor board.
** We have received complaints of early processor boards (C1900-0265) spontaneously recycling power during programming of the instrument. I was able to duplicate this problem in our shop (in particular, when changing input types) and the problem seems to only affect early processor boards with ISS. 7 firmware. The processor board works fine with ISS. 6, but any issues earlier than ISS. 7 will not support the new style I/O card. ABB Automation is currently researching this 'glitch', and I will post their findings here when available.
Photos of the older and newer design printed circuit boards
* The Display Board (C1900-0275/0276) is the only board that has remained the same