Pcmk

[Guest zstreed]

What is the difference between series A and B?

[Chris Elston 78]

PCMK...I don't have my AB catalog handy, but isn't that a DH+ card for a laptop? Er maybe it was a device net comms card? If so, I think the A and B there is a highest BAUD rate difference. I remember something like this before. Version "B" is a higher buad rate than "A". So if you communicate faster, get the version "B" card. Good Luck.

[Guest zstreed]

Sorry, yeah it's a pcmcia card for DH+ and DH-485, and comes in a series A and a series B, which appears to greatly influence price on auctions.

[Guest Ron Beaufort]

Yes, these are Allen-Bradley's PCMCIA-type cards for laptop computers. They are usually used for programming PLC's via DH+ communications. Besides the capability to handle higher baud rates, the cables used to connect the PCMK card to the PLC are different sizes. The older A version is about 1 inch wide where it inserts into the card. The newer B version is about 1/2 inch wide. If you're going to buy a new card/cable set, it's best to ask for part number 1784-PCMC. This is a kit which gets you a card, cable, and adapter - cheaper than buying the parts separately. The PLC end of the kit's cable is a standard DB9 male connection. The adapter changes this to an 8-pin mini-DIN connector for the DH+ programming port on "enhanced" PLC-5's and on the SLC-5/04. Remove the adapter and you can plug into the front of older "classic" PLC's like PLC-5/15 (which don't have an 8-pin mini-DIN connection). There is another (neater) cable available which already ends in the 8-pin mini-DIN. You won't need to mess with the adapter, but then you also won't be able to connect to an older "classic" PLC if you run into one in the field. And incidentally, don't try using a gender changer to connect the DB9 connector into the RS-232 port on the front of an SLC. This port is not DH+ and the PCMK can't communicate through it. Next, with the proper (additional purchase) cable, the PCMK card can also be used for DH-485 communications. Even beyond this, there are other cables available to connect to other AB products. Finally, if all you need to do is program "enhanced" PLC-5's and SLC-5/03's and up, you might not need the PCMK approach at all. These processors can (more or less easily) be programmed through their RS-232 "Channel 0" ports with simple null modem cables. Downside: beside slower baud rates, programming this way can be quite annoying (and sometimes impossible) if a PanelView, etc. is normally plugged into this port. Best regards.