Measurement Computing WBK40 - Manual (Page 6)

DIGITAL I/O (2 Terminal Blocks) POWER [Out] COUNTER - TMR D/A (DAC0, DAC1, DAC2, DAC3)
WBK41, Front Panel Connectors
Note that WBK40’s Front Panel is identical, except it has no screw-terminal blocks. Page 1 includes a photo of WBK40.
Page 2 includes a table that describes each item found on the front panel.
Note:
The row of terminal
blocks does not
apply to WBK40.
Thermocouple Connections
The WBK40 and WBK41 each accept up to 14 thermocouples [with mini-TC plugs] via channels 1
through 7 and 9 through 15. All channels have the same level of functionality.
Thermocouple wire is standardized, color-coded, and polarized, as noted in the following table.
Thermocouple Standards
T/C
Type
(+) Lead to
Channel High
(-) Lead to
Channel Low
J White Red
K Yellow Red
T Blue Red
E Violet Red
N28 Orange Red
N14 Orange Red
S Black Red
R Black Red
Mini-TC plugs are type-specific, and for best
measurement operation the plug TC type should match
the wire TC type. If necessary, copper/copper (Type U)
plugs may be used, but measurement stability will be
slightly degraded. Mini-TC plugs are polarized as well,
and it is critical for proper measurement operation that
this polarity be followed when connecting the
thermocouple wire. Once wired, the TC plugs will only
mate into the unit’s TC connectors in one orientation,
thus ensuring a correct connection.
B Gray Red
It should be noted that thermocouples output very small voltages and that long thermocouple leads can
pickup a large amount of noise. However, both the WBK40 and WBK41 inherently provide a high level of
noise immunity via their 4 Hz signal bandwidth and input filtering. If desired, further noise reduction can
be achieved through the use of shielded thermocouples and/or averaging.
You can minimize the effect of noise by:
(1) using shielded thermocouples
(2) averaging readings
(3) employing both of the above practices
To accommodate shielding, grounded connections, labeled “Analog Common,” are provided. A typical
use of the connection would be to attach the shield of a shielded thermocouple. Note that the Analog
Common connector is removable to facilitate wiring.
If a thermocouple shield is connected to a WBK40, or WBK41 module, leave the shield
unconnected at the other end of the thermocouple.
pg. 6, WBK40 & WBK41 926896 Thermocouple and Multifunctional Modules