13-4
BCD Option
13
13.4 50-LINE CABLE COMPATIBILITY
The 40 lines of the BCD connector are compatible with lines 9 through 48 of
some 50-line busses (left-most 8 and right-most 2 are not used by this BCD
option).
13.5 SELECTING THE SOURCE OF BCD DATA: “OUT.CNF”
If “L3C.7=0” has been selected to unlock the OUTput CoNFiguration byte,
set “OUT.3=1” to send data to this BCD board. “OUT.4=0” selects that data
as the DISPLAYED (current) measurement value. “OUT.4=1” sends the
PEAK (HI) value to the BCD. Save your selection by pressing the
‘MENU’
button.
13.6 HOLD CONTROL
P8-U17 is the HOLD line, referenced to the same ground as the BCD
outputs (on P8-L15 and P8-L3). Pulling this line low freezes the BCD outputs
(useful for a slow reading device or asymmetric cable delays).
When released, all 6 digits of the BCD data are updated together.
13.7 DATA READY TIMING PULSES
The tri-state BCD outputs are always valid (to within a few nanoseconds; a
single update pulse controls all the digits).
To generate a timing marker, P8-L16, DATA READY, goes active low for
approximately 200 microseconds at the time of each BCD update. The
polarity of this line is NOT CHANGED by S8, the data polarity control jumper.
13.8 BRINGING OUT THE BCD OVERFLOW LINE
P8-U18 can be used for BCD OVERFLOW by inserting jumper S1A. If this
line is used for another purpose by some other equipment on the BCD bus,
remove this jumper.
13.9 3 DIGIT AT A TIME MULTIPLEX
When jumpers S2A, S3A, and S4A are used, P8-L20 and S5C control when
the upper 3 digits of the 6-digit BCD value appear on the output line (P8-U9
through P8-L14).
With jumper S5C, a LOW level on P8-L20 activates those upper 3 digit
outputs; a high or open level disables those digits.
With jumper S5C removed, a high or open level on P8-L20 enables those
upper 3 digits and a low level disables them.
When the upper 3 digits are NOT enabled, the lower 3 digits can be enabled
in just the same way by jumper S5A and P8-U20, and they now appear on
the same 12 lines.
Summary of Contents for DP461-S
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