Spectrum Controls 140 ACI 052 00sc - Manual (Page 50)

6.2 Demultiplexing Channel Data - Autosequence Mode
The autosequence mode of operation is intended to simplify the demultiplexing
of channel data from the eight input registers into storage for the 32 channels.
The autosequence mode is enabled under the following conditions:
• Input Mode = Data Mode (Configuration Word Bits 11 & 12 = 0)
• Autosequence Disable is not active (Configuration Word Bit 10 = 0)
In the autosequence mode, the group select bits in the configuration word are
ignored. Instead, the module samples channel data in groups of eight (8),
presents the data to the PLC and then scans the next group automatically.
The ladder logic then reads the status word to determine which data is being
presented and copies the data to the appropriate storage locations for those
channels.
The module update rate is determined by the number of channels enabled and
the filter frequencies selected. For example, if all 32 channles are enabled
and the filter frequency for all groups is 60 Hz, then the cycle time for a full
set of 32 channels is 32 x 58 msec or 1.856 seconds.
It takes four ladder logic scans of the eight registers to see all 32 channels.
These four scans must be completed at least twice as fast as the module update
time to ensure no data is missed. In the example above the ladder scan time
would need to run at 1.856 sec/8 or 232 msec or faster to ensure no data is
missed.
Refer to Section 4.4 Channel Update Rate for channel update times.
6.3 Using ladder to move data to a block of 32 consecutive registers
The following ladder logic shows how to move data from the 8 multiplexed input
words to a block of 32 output words starting at location 400101 with the autosequence
mode disabled. This example file for use only with Modsoft programming software
can be found on the install disk shipped with your module. The file is under the
A:\Programs subdirectory. To install:
1. Insert the install disk into drive A:
2. Copy A:\Programs\QAI32_AC.* C:\Modsoft\Programs
3. Select File QAI32_AC under Modsoft to run.
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Installation Instructions
32-Channel Analog Input Module
Quantum 140 ACI 052 00sc