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I-1
Appendix I. Control Bits
For diagnosing a problem using data saved in the output table,
ts_data
, the
state of fans and heaters is encoded into variable
ControlBits
to conserve
memory space. A user unfamiliar with converting a decimal number to binary
may find it convenient to use a decimal-to-binary converter that can be found
on the Internet. Alternately, follow the step-by-step troubleshooting
instructions as a guide through the conversion process.
Note: the CPEC300 controls power to the heaters and fans with a 16-channel
control module, the SDM-CD16S. This same module controls the valves and
the scrub pump, as noted in the table. The state of the valves and scrub module
are set by
valve_number
, and are not reported in
ControlBits
.
TABLE I-1. CPEC300 temperature control bits encoded in ControlBits
Binary Bit
(LSB = 1)
Numeric
Value
Corresponding
public variable
(bit is set if
variable=True)
Notes
14 - 16
Not used
13
4096
scrubFan_ON
Scrub module fan is on
12
2048
scrubHeat_ON
Scrub module heater is on
11
Used for scrub pump (not included in
ControlBits
)
10
512
pump_fan_ON
Sample pump fan is on
9
256
pump_heat_ON
Sample pump heater is on
8
128
valveFan_ON
Valve module fan is on
7
64
valveHeat_ON
Valve module heater is on
1 – 6
Used to switch valves (not included in
ControlBits
)
none
0
All heaters and fans are off
If
ControlBits
is greater than 4095, this indicates bit 13 of
ControlBits
is set.
This means the scrub module fan is on. To decode other temperature control
bits, subtract 4096 from
ControlBits
and compare the remainder to the bit
values below.
If
ControlBits
is greater than 2047, this indicates bit 12 of
ControlBits
is set.
This means the scrub module heater is on. To decode other temperature control
bits, subtract 2048 from
ControlBits
and compare the remainder to the bit
values below.
If
ControlBits
is greater than 511, this indicates bit 10 of
ControlBits
is set.
This means the sample pump fan is on. To decode other temperature control
bits, subtract 512 from
ControlBits
and compare the remainder to the bit
values below.
If
ControlBits
is greater than 255, this indicates bit 9 of
ControlBits
is set.
This means the sample pump heater is on. To decode other temperature control