Using the IntelliLogger™
39
the ILIM-7 is housed within another enclosure, which will provide better temperature
uniformity throughout the system.
Vdc-Lo Applications
All of the ILIM-7 input channels can be configured for low-level Vdc input per the
switch settings shown in Table 1-1. The configuration switch settings to
configure a channel as a Vdc-Lo input are the same as the setting when using
the channel as a thermocouple input channel. The selection of thermocouple or
Vdc-Lo as well as selection of sub-ranges is performed from within HyperWare-II
in the input icon Configuration dialog. Clicking a button within the dialog swaps
the channel function.
For best accuracy and absolute resolution, utilize the lowest range
possible that will cover the input signal's dynamic range without over-
ranging.
S
IGNAL
W
IRING
C
ONNECTION
:
Interface Module channels configured as VDC inputs provide three terminal strip
connections per input; a Positive lead, and a Negative lead and a Shield connection.
Connect the VDC signal positive and negative leads to the correct pair of terminals on
the module terminal strip (Figure 3-9). Observe polarity or the output signal will be
reversed.
Shielded and/or twisted pair wire is recommended in electrically noisy environments
for optimum signal protection. If shielded wire is used, the shield should be connected
to the terminal marked ‘SH’. The Shield serves to conduct away electrical noise
picked up by the thermocouple shield and shunt it to Earth ground. Note that for the
Shield to be effective, a wire should be connected from any of the Shield connections
on the ILIM-7 terminal strip and then to a known Earth ground. All Shield connections
on the terminal strip are interconnected so a single Earth ground connection suffices.
Shielded wire minimizes the amount of noise picked up by the internal
conductors carrying the signals by providing an `electrical shell' or
Faraday cage around the internal conductors.
Twisted pair wiring exposes both conductors equally to the ambient
electrical noise. This common-mode type noise is easier to reject by
the Interface Modules input signal conditioning circuitry than
unbalanced (or differential) noise.
Vdc-Hi Applications
Channels A through D have additional input range capability in that they can be
field configured to directly accept up to +/-30Vdc. Vdc-Hi Input Configuration
Switch setting (Table 1-1) enables a front end precision voltage divider circuit
which expands the channel’s acceptable input range. Correction for the
precision front-end resistor divider is handled automatically and transparently by
the ILIM-7 so no user scaling for the divider is required.
Selection of a sub-range is performed within the HyperWare-II Icon Configuration
dialog for that channel.
