32 VMIVME-1184* 32-bit Optically Isolated Change-of-State (COS) Input Board
Publication No. 500-001184-000 Rev. B.0
3.2.3 Counter Connectivity
Bits 31-19 and Bit 15
: Unused (reserved for future use).
3.2.4 Quadrature Counter Decoder Bits (Bits 16, 17 and 18)
Bits 18 and 17 =
Set debounce times
0 0 = 62.5nS
0 1 = 125nS
1 0 = 1uS
1 1 = 10uS
Bit 16:
1 = Disable AB debounce (note: Marker is always debounced per
debounce times below)
NOTE
The minimum, or no debounce is used in quadrature mode to help the capture of quick AB transitions
during equipment stoppage. Some debounce should be used in Counter modes. The use of differential
signaling helps reduce noise problems in long cable runs or noisy motor environments.
Bits 14 - 08 below are used for Counter Connectivity.
Bit 14:
RW, Counter Connectivity Warning.
0 = Okay
1 = Change or Conflict Warning.
The connectivity status for all six wires is latched-in as VME_SYSRESET goes
away. If a conflicting configuration is attempted, this bit is set. For example, trying
to use 2 channels without a
ʺ
B
ʺ
wire connected. Also, if a connectivity change
occurs after RESET, then this bit is set as a warning indication. Writing a
ʺ
0
ʺ
to this
bit forces a re-read of the latest wire status and may clear the warning, if it is not a
conflict warning. Conflicts cannot be cleared without actually taking care of the
conflict.
Some possible conflicts are:
No A+ connection
No B+ when CSR1_[5] (two channel operational mode) is set
No marker connection (+ or -) detected when CSR1_[1] (marker clear counter) is
set or ip_ctl[31] (marker interrupt) is set.
Bits 13-08:
Read only,
ʺ
Broken Wire
ʺ
Quadrature Counter input connectivity
status.
ʺ
0
ʺ
= okay, connected.
ʺ
1
ʺ
= Unconnected
13: A+ wire status
12: A- wire status
11: B+ wire status
10: B- wire status
09: M+ wire status
08: M- wire status
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