Goals and Symptoms

The purpose of this resolution is to inform the user on the behavior when using the command GetIDN_S (opcode 1556) or Get IDN_P ( opcode 1557 ) from a Quantum (or) a Premium SERCOS Controller.

Facts and Changes

When a 2 bytes IDN is gets the PLC haven't any possibility to know if the value is signed or not. So, the PLC register accommodate values from -32767 to + 32767 in signed format
Due to the above reason, values for IDN_S ( or _P ) 2 bytes set higher than 32767 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 GetIDN_S ( or _P ) 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 SetIDN_S ( or _P) command for the same IDN which is Unsigned decimal format.

Goals and Symptoms

The purpose of this resolution is to inform the user on the behavior when using the command GetIDN_S (opcode 1556) or Get IDN_P ( opcode 1557 ) from a Quantum (or) a Premium SERCOS Controller.

Facts and Changes

When a 2 bytes IDN is gets the PLC haven't any possibility to know if the value is signed or not. So, the PLC register accommodate values from -32767 to + 32767 in signed format
Due to the above reason, values for IDN_S ( or _P ) 2 bytes set higher than 32767 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 GetIDN_S ( or _P ) 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 SetIDN_S ( or _P) command for the same IDN which is Unsigned decimal format.