Advanced Micro Controls Inc. 1700 Series User Manual page 49

Chapter 5 PLC-5 BT Instructions
PLC-5 Restrictions and Warnings
hý It is important to have the 1700 module installed in a single slot pair.
Installing the Module.
hý When using the 1700 module in a remote chassis, the Remote I/O Adapter must be a
1771 - ASB, Series B, Firmware Rev. F, or later. Using a Remote I/O Adapter that has
an earlier Series or Firmware Revision may not work properly with a 1700 module.
hý When the processor enables a block transfer, it puts all of the needed information into a queue.
A queue is a data structure where the first piece of information put into the queue is the first
piece of information taken out. Once the information is queued, a separate part of the processor
performs the block transfer while the rest of the processor continues with the program scan.
Each I/O rack in the system has it's own queue. Each queue can hold 17 BT requests. When
the block transfer has its Continuous bit set to 1, Continuous Parameter is "YES", the Block
Transfer is placed permanently in the queue.
Each queue has a "Queue Full" bit in word 7 of the processor's status file. Bit 8 is for Rack 0,
Bit 9 is for Rack 1, and so on up to bit 15 for Rack 7. The appropriate bit is set when a queue is
full of BT Requests. Once set, your ladder logic program must clear these bits. We recommend
that your program monitor these bits and take appropriate action if these bits are set.
If you have more than 17 block transfers associated with one rack and you set all of their
continuous parameters to YES, only the first 17 block transfers scanned will be performed. All
other transfers cannot be put into the queue and will never be performed.
5-4
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
See chapter 3, pg. 3-1,
ADVANCED MICRO CONTROLS INC.