The system and the Standard [t-head1-pg]

European Standard EN 50011 “Terminal markings, reference numbers and reference letters for certain contactor relays” has a direct bearing on the use and application of the modular system. There are various types, which the Standard differentiates between by means of reference numbers and reference letters, depending on the number and position of the make and break contacts in the device, and their terminal markings.

Ideally devices with the reference letter E should be used. The basic devices DILA-40, DILA-31, DILA-22 as well as DILER-40, DILER-31 and DILER-22 comply with the E version. .

For 6 and 8 pole contactor relays, the “E” version means that four make contacts must be arranged in the lower/rear contact level. If, for example, the available auxiliary contact modules are used in the DILA-22 and DILA-3131, they result in contact combinations with reference letters X and Y.

Below are 3 examples of contactors with 4 normally open and 4 normally closed contacts with different reference letters. Version E is to be preferred.

Example 1		Example 2		Example 3
DILA-XHI04		DILA-XHI13		DILA-XHI22
+ DILA-40		+ DILA-31		+ DILA-22
44 E DILA40/04		44 X DILA31/13		44 Y DILA22/22