Littelfuse M1500 Series - Manual

• 6 inputs for PT100 resistors
• 6 current outputs 4-20mA according to DIN
EN 60751 & IEC 751
• Can be used together with the SELCO
M3000 Analog Alarm Annunciator
• Cost effective and highly reliable compact
design
• 50 hours burn-in before final test
• Operating temperature range:
-20°C to +70°C
• Flame retardant enclosure
• DIN rail and screw mounting
The M1500 provides a cost effective solution
and includes 6 current transmitters in one box
to be connected to temperature resistors. The
unit can be used in connection with the
SELCO M3000 Analog Alarm Annunciator.
The PT100 resistors are connected at the
inputs illustrated in fig. 1. The resistance of
PT100 resistors depends on the temperature.
The reason for the middle terminals (e.g.
terminal 2) is to compensate for resistance
in the cable.
The outputs are 4-20mA current out-puts, also
illustrated in fig. 1.
The output current is 4-20mA for
temperatures 0-160°C, 0-300°C or 0-600°C
according to DIN EN 60751 & IEC 751.
The temperature range is selected for each
input on the front panel.
The ratio between current and temperature is
linear, meaning that for 0-160°C PT100
resistors, 0°C corresponds to 4mA, 80°C
correspond to 12mA and 160°C correspond to
20mA.
Fig. 2 illustrates the connections to one input
group of the M3000 Analog Alarm
Annunciator. The reference resistor R should
be used with M3000-20 Analog Alarm Annunciator,
but not with the newer version instrument M3000-30.
The resistor should be 261
 ¼W with a tolerance of 0.1%.