Measurement Computing WBK40 - Manual (Page 16)

In regard to adding thermocouples to WBK40, WBK41, or DBK84 modules, Channels 1 through 7 are used for the
first seven thermocouples, and channels 9 through 15 are used for the second set of seven. Channels “0” and “8”
are not used for thermocouple input, but instead measure the two CJCs.
In addition to thermocouple measurements, each input channel can be configured for a fixed voltage gain
of 100. When in this mode, voltage can be measured in the range of ±100 mV.
Built into the WBK40 and WBK41 is a 16 bit, 200-kHz A/D converter that samples all of the TC inputs, including
inputs attached to the DBK84 expansion modules. The SYNC connection between the WBK40 or WBK41 module
and the WaveBook/516E ensures that thermocouple measurements on the module are synchronized with higher-
speed measurements on the WaveBook. WaveBook software automatically compensates for the difference in
sampling rates between the WaveBook and WBK40 [or WBK41], ensuring that there is exact time correlation
between readings from both devices.
The WBK40 and WBK41 automatically perform thermocouple linearization and cold-junction compensation,
providing accurate and stable temperature readings in either °C, °F, or °K. Typical TC accuracy is better than 1.0°C,
with channel-to-channel variation and noise typically better than 0.2°C.
Digital I/O, WBK41 Only
Forty Digital I/O lines are built-into the WBK41. Sixteen are accessible via front-panel removable screw terminal
connectors, and can be defined under program control as either all inputs or all outputs. As inputs, these channels
can be scanned synchronously during an acquisition, or asynchronously under program control. As outputs, these
lines can be set prior to an acquisition, or changed during an acquisition if used with a programming environment
such as Visual Basic®, C, or LabVIEW®.
In addition to the 16 front-panel Digital I/O lines, 24 lines are provided on the rear panel 37-pin D connector,
designated as P2. These lines are logically divided into three 8-bit ports, with each port programmable as input or
output. As with the front-panel Digital I/O, these lines can be scanned as inputs along with other channels in a scan
group, or read during an acquisition when a programming environment is being used.
Note that P2 can be used as a Digital I/O expansion port. In this role it can be expanded up to 256 digital I/O lines
using our DBK20 Series options. DBK20 Series devices provide additional signal I/O, including optical isolation
and relay closure. The DBK Option Cards and Modules User’s Manual (457-0905), which is included in PDF
format on your data acquisition CD, contains details regarding each DBK20 Series device.
Synchronous Input Operations
The WBK40 and the WBK41 allow synchronous scanning and acquisition of Thermocouple Inputs. This type of
data can be from either the WBK40, the WBK41, or from DBK84 expansion modules. In addition to
Thermocouple Input, the WBK41 can receive Digital Input and Counter Input Data at up to 200kHz aggregate
scanning rates. The WBK41 can input Digital Data through its Digital I/O terminal blocks [on the front panel], or
via its DB37 P2 connector, which can be used to expand to a DBK20 Series card or module.
Digital Input Channels
The WBK41 allows for either synchronous scanning of digital input channels or asynchronous I/O operations for all
configured digital channels.
pg. 16, WBK40 & WBK41 926896 Thermocouple and Multifunctional Modules