Cold Junction Compensation; Differential Measurement; Measuring Points List - Ahlborn ALMEMO 2590-2A Operating Instructions Manual

mospheric pressure compensation can by means of ´#N´ in the des-
ignation (see 13.2) be converted to standard conditions of 1013
mbar.

Cold junction compensation

11.2.6
Cold junction compensation for thermocouples is normally performed automati-
cally by means of an NTC sensor in measuring socket M2. This cold junction
temperature is displayed in the device configuration as an operating parameter
(see 14.8). This can if necessary be incorporated in measured data acquisition
as device temperature with function channel ´CJ´ (see 13.10). Instead of this
form of cold junction temperature measurement it is also possible to use an ex-
ternal measuring sensor (Pt100 or NTC) in an isothermal block (see Manual
6.7.3); this must be positioned upstream from the thermocouples and ´*J´ must
have been programmed in the first two positions in the designation (see 13.2).
For especially exacting requirements (e.g. for thermocouples for which there is
no connector with thermo-contacts or for large temperature differences caused
by thermal irradiation) special connectors are available, each with its own inte-
grated temperature sensor (ZA-9400-FSx) for cold junction compensation.
These can be used for all thermocouple types; however, they require 2 measur-
ing channels. Having "#J" programmed in the first two positions in the designa-
tion for the thermocouple ensures that the temperature sensor integrated in the
connector is indeed used for cold junction compensation.

11.3 Differential measurement

If two sensors with the same units and same decimal point position are con-
nected at measuring points M0 and M1, the difference M1 - M0 appears auto-
matically below device-internal measuring point M2/M3/M4 (see 8.2). If the dif-
ferential channel is not required, it must be explicitly deleted; (see 13.9). If fur-
ther differential channels are needed, these can also be created using the ap-
propriate reference channels (see 13.12.6).

11.4 Measuring points list

The best overview of all measuring points with
measured values and function values is obtained
via the menu
Measuring points list
This menu cannot be configured by the user; it
can only be combined with certain selected
functions.
Initially the list appears with maximum 12 entries.
Measured values
To select further measuring points press key(s)
The measured value can be linked to a series of
.
11. Measuring menus
Measuring points list 12 meas-
ured values
00: 23.12°C ...
< F ►> ...

31