Here’s what more than 2,500 business decision-makers around the world say.Download the report
...with the Facility Hero app in hand! Discover how you can optimize your maintenance efforts today.Learn more
Access tailored services, 24/7 self-service and expert help. Anywhere, anytime, any project.Discover now
Don’t miss the latest events, videos, or articles. It’s all in our news bulletin.Sign up now
Schneider Electric Global Website×
Explore our global offerings or select your country from one of our five regions.Global
Découvrez nos offres globales ou sélectionnez votre pays dans l’une de nos cinq régions.
Goals and Symptoms
The purpose of this resolution is to inform the user on the behavior of IDN 100 ( Ascii equivalent GV) when using the command ReadIDN_S (opcode 1556) from a Quantum (or) a Premium SERCOS Controller.
Facts and Changes
The data length of IDN 100, as described in the IDN user manual (version 2.0, June 2003) is 2 bytes. The PLC register can hence accommodate values from -32767 to + 32767 in signed format. Although the IDN document lists the maximum value for IDN 100 as 200, GV can have values higher and calls for data length greater than 2 bytes in the PLC register, due to its scaling ( GV*100). However the 2 byte limitation is in compliance with the SERCOS standard for this IDN.
Due to the above reason, values for IDN 100 set higher than 32767 (GV = 327) when read, will be returned as follows:
(i) 32768 -> -32768
(ii) 32769-> -32767
(iii) 35000 -> -30536 in signed format. Unsigned format will result in a huge number.
Causes and Fixes
When ReadIDN_S returns a negative value, it may be converted to its positive equivalent by adding 65536.
For example, -30536 + 65536 = 35000 and so on. There is no implication on using the WriteIDN_S command for the same IDN which is Unsigned decimal format.