Question:
What has to be considered when the absolute value encoder is put into operation at the ECS Posi&Shaft?
Answer:
In case of the ECS Posi&Shaft the absolute value encoder can be mounted to the machine in any way regarding its display range. The other adaptations are made with the software. The overflow point within the absolute value encoder is not important. For the adaptation by software it is required during commissioning to start a profile set
once with the profile mode 'Set home position'.
Commissioning process:
- Select motor etc.
- C0419 = 410 (select feedback system (example: multiturn absolute value encoder with 512 sine/cosine periods)
- C0490 = 4 (feedback system for positioning control: absolute value encoder)
- C0495 = 4 (feedback system for speed control: absolute value encoder)
- C0421 = 5 (voltage supply encoder = 8.1 V)
- Control: C0427 = 0 ; C0491 = 0
- C0580 = 0 (activate Sd8-encoder-monitoring on Trip)
- C0586 = 3 (Sd2-resolver-monitoring Off, as in the example no resolver is connected)
- Store parameter with C0003 = 1 and then
- Switch 24V-voltage supply, in order to execute reinitialisation (the absolute value of the encoder is newly read)
- Set C3095/x = 101 ('set home pos') one during commissioning
Set reference once:
For setting home position set mode 'set home pos' (C3095/x = 101) in a positioning profile and start the profile. The profile can, e. g., be selected and started via the application control word C4040. As control interface please switch to code digits (C4010 = 3).
Control: Status bit for home position known 'Stat1.HomePosAvailable' must be set (status word C4045 Bit13 = 1).
Important: The controller
must be ready to operate (RDY = 1)
but inhibited (controller inhibit CINH = 1), otherwise the home position is not assumed and the status 'Home position known' (HomePosAvailable) is not set.
The displayed actual position is set to 0 by setting home position (controller-internal offset-variables). The value in the encoder is not influenced. See also article
Absolute value encoder, set home pos. only when the controller is inhibited (Doc-ID 200603850).
After an encoder-, controller- or motor exchange, as well as after modifications of the mechanics home position is once to be set again.
Advantage ECS:
By means of corresponding offset variables the ECS Posi&Shaft 'remembers' the position of the home position in relation to the encoder's overflow point. Finally, the ECS Posi&Shaft is not limited to the 4096 revolutions of the absolute value encoder that can be displayed, but the max. display area is available - just as it is available to the resolver. Condition: In switch off mode the absolute value encoder is not moved more than +/- 2048 revolutions (in practice this will be easily ensured).
Comparison:
In case of 9300EP positioning controller the travelling range must be within the display area of the absolute value encoder (4096 rev.) and the overflow point of the encoder must be outside the travelling range.
Zero point shifting by means of code C0098, see article
Absolute value encoder of SPLC and ECS, set reference position with C0098 (Doc-ID 200506868).
