Here is a select representation of documentation that viewers will find helpful.  These links go to my Google Drive account.

Some of the manuals are quite large in size and will need to be explicitly downloaded through the link as the Google preview function has a self-imposed file size limit.

Manual – Lectron Lab – For Series 4 and 5 – ENGLISH

Manual – For 800 and 820 Models – ENGLISH

Manual – For Series 1 through 5 Models – ENGLISH

Manual – Supplementary No. 1 – For Series 1 through 5 Models – ENGLISH

Manual – Supplementary – For AddOn #6 – ENGLISH

Manual – Supplementary – For AddOn #7 – ENGLISH​