cations. They are not marked on modules since the locations may change de-
pending on how modules are attached. Channel numbers are assigned in
sequence, starting with 1, from left to right, front to back. The left-most chan-
nel on the first module is channel 1, the next channel on the right is channel 2,
etc. The sequence continues with the next module in the same fashion (see Fig-
ure 7). Output channel numbers are assigned using the same scheme.
4.5.2
Selecting the Probe Characterization
Before the 1560 can accurately measure temperature, it must know how to cal-
culate temperature from the resistance or voltage of the sensor. There are many
temperature conversion algorithms available and the one to use depends on the
type of sensor and its calibration. Many conversion algorithms use coefficients
that characterize the sensor. Coefficients are determined when the sensor is cal-
ibrated. SPRTs and RTDs often use the ITS-90 algorithms and are provided
with ITS-90 characterization coefficients. Thermistors often use the
Steinhart-Hart algorithms and coefficients. Thermocouples use standard tables
or equations depending on its type.
The conversion type and characterization coefficients for a sensor are specified
using the
EDIT PROBE
soft-key in the
PROBE
menu (see Section 5.2.1).
First you must select the channel to which the sensor is connected. A window
appears showing a list of all available channels. Each channel in the list is iden-
tified with the device name, the channel number, and the serial number. The
channel is selected using the
UD
buttons and pressing
ENTER
.
SELECT A CHANNEL TO EDIT
>SPRT 01, PROBE 566-011
SPRT 02, PROBE 566-012
TCS
03, PROBE 1341
TCS
04, PROBE 1342
TCS
05, PROBE 1343
TCS
06, PROBE 1344
$
Next, you select the conversion type and enter characterization coefficients, if
necessary. You can move to any parameter in the window with the
UD
but-
tons. After changing the value for any parameter you must press
ENTER
for
the new value to be accepted.
25
4 General Operation
Making Measurements
