encoder’s multi-turn value range from 0 to max will be mapped to 0 to max; the
second half of the measuring range will be initialized as positive; in this case, the
point of discontinuity will be found at 0.
If you set MTEnable to 1, you can use an available multi-turn encoder as a single-
turn encoder (this is only needed for testing purposes).
If you set EncObsMin to 0, Sin/Cos wire break monitoring will be disabled. The
default value is 0.2 (20%) and stands for a calculated amplitude value (calculated
using the two Sin/Cos signals) of x = sqrt(a^2 + b^2). If the Sin/Cos signals are equal
to approx. 1 Vss when compared, approx. 0.8 will be calculated here (approx. 80%
magnitude at the A-D converters; approx. 0.25 Vss Sin/Cos will yield approx. 0.2
here (20% magnitude at the A-D converter)). The error threshold can be set with
EncObsMin within a broad range.
NOTE
l
As there are various protocol modes available for SSI encoders
(with/without wire break monitoring, with/without parity bit, etc.),
consult with your project supervisor or the Helpline provided by
Moog before using any special SSI protocol modes.
6.5.2 EnDat (cyclical) X7
Ch1: ENDAT(4) - Cyclical EnDat (2.1 or 2.2)
EnDat is a digital encoder interface developed by HEIDENHAIN. For more details,
please visit
and go to ►Documentation ►Fundamentals
►Interfaces ►EnDat 2.2..
The software versions required to run the EnDat encoder interface are the standard
software versions for the MSD Servo Drive and MSD Single-Axis Servo Drive
Compact.
MOOG
ID No.: CB40859-001 Date: 11/2020
MSD Servo Drive - Device Help
61
6 Encoder
NOTE
l
Please note the limitations that apply when running EnDat and
SSI encoders (see Section "Limiting for EnDat and SSI" on page
52).
When using linear encoders, P 554[0] - ENC_CH1_DigitalResolution is used
instead of P 543[0] - ENC_CH1_MultiT and P 544[0] - ENC_CH1_SingleT (which
are used for rotary encoders). The values will be read from the EnDat encoder and
written to the aforementioned parameters.
l
P 543[0] - ENC_CH1_MultiT
The number "n" of multiturn bits defines the measuring range in 2
n
increments per encoder shaft revolution; maximum travel until overflow;
maximum travel within which the absolute value initialization can be
unambiguous. In the case of single-turn encoders, MultiT = 0.
l
P 544[0] - ENC_CH1_SingleT
The number "n" of single-turn bits corresponds to the encoder’s digital
resolution in 2
n
increments per encoder shaft revolution.
l
P 554[0] - ENC_CH1_DigitalResolution
This is the length of an increment, in nanometres, of the encoder’s digitally
transmitted position value. This value is read from the EnDat linear head.
In the case of linear encoders, the number n of transmitted position bits from the
encoder will be found in SingleT only! 2
n
* DigitalResolution yields the maximum
travel in nanometres (for the encoder head).
P 640 - ENC_ENDAT is intended for additional information, but is normally
not
needed. This parameter does not have a Ch1 or Ch3 prefix for the encoder channel
in the name, as it applies to both encoder channels. Although usually not needed,
the parameter is helpful or required in the following cases:
1.
Special EnDat encoder with diagnostics for evaluation
In this case, the valuation numbers from the encoder are read cyclically via
additional information. Only the valuation numbers that the encoder supports
