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4
Reset
Clock
No Channel
Selected
1.2.2 GK-403 Mode of Operation
(Please note: The GK-403 is an obsolete model. This mode of operation has been
retained for legacy purposes.)
The GK-403 mode of operation uses a single control line to select channels. This scheme
allows individual channels to be selected without having to sequentially advance through
all channels. Multiplexers can also be connected together in a "daisy-chain" fashion using
the GK-403 protocol. In 16-channel mode, the number of clock pulses equals two times
the desired channel number. In 32-channel mode, the number of clock pulses equals the
desired channel number plus one. Note the timing for 16-channel (shown in Figure 7) and
32-channel (shown in Figure 8) switching arrangements.
The GK-403 channel selection scheme is not well suited to long cable lengths. The
maximum recommended distance between the GK-403 and multiplexer is 50 feet (15
meters).
T1
T2
T3
T4
Clock
Channel Selected
T1
T2
T3
Pulse 1
Pulse 2
Channel 1
Selected
Timing:
T1 = 50 mSec (min)
T2 = 2 mSec (min)
T3 = 4 mSec (min)
Figure 6 - 32-Channel Datalogger Channel Selection Timing
1
2
Figure 7 - 16-Channel GK-403 Channel Selection Timing
Channel 2
Selected
Timing:
T1 = min 20 usec
T2 = min 20 usec
T3 = min 40 µsec (25kHz)
T4 = 500 µsec
1
2
Channel 1
Pulse 32
Channel 32
No Channel
Selected
Selected
4
3
Channel 2
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