9
5.
INTRODUCTION
The ALMEMO
®
2490A is a new member in our family of unique measuring de-
vices - all equipped with Ahlborn's patented ALMEMO® connector system. The
intelligent ALMEMO® connector offers decisive advantages when connecting
sensors and peripherals because all parameters are stored in an EEPROM lo-
cated on the connector itself; repeat programming is thus no longer necessary.
All sensors and output modules can be connected to all ALMEMO® measuring
instruments in the same way. Programming and functioning are identical for all
units. The following points apply to all devices in the ALMEMO® measuring sys-
tem; these are described in detail in the ALMEMO® Manual which is included in
delivery with each device.
Detailed explanation of the ALMEMO® system (Manual Ch 1)
Overview of the device functions and measuring ranges (Manual Ch 2)
Basic principles, operation, and technical data for all sensors (Manual Ch 3)
Options for connecting your own existing sensors (Manual Ch 4)
All analog and digital output modules (Manual Section 5.1)
Interface modules USB, RS232, optic fiber (Manual Section 5.2)
The whole ALMEMO® networking system (Manual Section 5.3)
All functions and their operation via the interface (Manual Ch 6)
Complete list of interface commands with all the printouts (Manual Ch 7)
The operating instructions you are now reading cover only those features and
controls that are specific to this device. Many sections therefore also refer to the
more detailed description in the Manual; (see Manual, Section xxx).
5.1
Functions
The ALMEMO® 2490-1A has one electrically isolated measuring input suitable
for all ALMEMO® sensors; the 2490-2A has two such measuring inputs. The
measuring possibilities are virtually unlimited; there are 4 channels per sensor
connector and 4 device-internal function channels (type -2 only) - with over 70
measuring ranges. For operation purposes the device incorporates a large LCD
display and a keypad. An option is available with an internal electrically isolated
analog output including a DC socket for a mains adapter (socket P0). The stand-
ard version with interface has three output sockets, namely A1 and A2, suitable
for all ALMEMO® output modules, e.g. analog outputs, digital interfaces, trigger
and relay cables, plus a DC socket for a mains adapter. Several devices can be
networked by simply linking them together via cable.
5.1.1
Sensor programming
The measuring channels are programmed, completely and automatically, by the
ALMEMO® connectors. The user can freely supplement or modify this program-
ming; this applies to the interface version only. However, devices without the
interface also behave according to all the programmed parameters.
Measuring ranges
Appropriate measuring ranges are available for all sensors with a non-linear
