Lake Shore Model 370 AC Resistance Bridge User’s Manual
4.11.8
Controlling and Scanning
The Model 370 and 3716 Scanner allow both temperature control and data taking at the same time. Firmware in the
Model 370 manages automatic switching between the control channel and scan channel and will maintain the control
heater output when the control channel is not active. Scanning during closed loop temperature control will never be as
stable as dedicated control instrument but with proper setup acceptable performance can be achieved for many
applications.
4.11.8.1 Reading
Sequence
The instrument takes control of the reading sequence when controlling temperature with one scanner channel and
measuring on another. It will alternate between the control channel and selected scan channel as quickly as possible so
that control is not suspended for longer than necessary. If autoscan is enabled, the instrument will read the control
channel between each active scan channel. It forces the scan dwell time to five seconds for the control channel and one
second for other reading channels.
4.11.8.2 Settling
Time
Settling time on channel change is very important when alternating between control and other readings. Longer settling
times suspend active control for longer periods of time increasing instability. The change pause must be set appropriately
for each active channel and the filter should have as short a settling time as possible. Filter should be turned off for
control.
4.12 MAX/MIN
CAPTURE
The Max/Min feature automatically captures the largest and smallest valid readings taken since the last reset. The feature
operates at the full update rate of 10 readings per second. It is suspended during range or channel change and captured
readings are lost when power is turned off. The maximum and minimum readings can be displayed in any of the 8
reading display locations (Paragraph 4.4.1). The Model 370 will only capture Max/Min data from one data source per
channel. The Max/Min feature uses filtered reading data when the filter is enabled.
To select a Max/Min data source the
Max/Min
key and press
Enter
to skip past the reset screen. If a scanner is installed,
the first input setup screen appears as a prompt for the channel number. If no scanner is installed, the sequence will begin
below with source selection.
Max/Min Setup
Select With °®
Channel: 1
Use the
s
or
t
key to select a channel number between 1 and 16. Choose the selection “All” and the changes will be
applied to all channels at the same time. Press
Enter
to accept the new selection and continue to the next setting screen.
Press
Escape
to cancel the new selection and return to the normal display.
The next display setup screen appears as a prompt for the source of Max/Min data for the selected channel. Changing the
data source will reset captured values for the selected channel.
Max/Min Setup
Channel 1
Select With °®
Data Source: Ohms
Use the
s
or
t
key to select one of three data sources, ohms, Kelvin, or linear (result of the linear equation). Press
Enter
to accept the new selection and return to the normal display. Press
Escape
to cancel the new selection and return
to the normal display.
Operation
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