HEIDENHAIN PWM 8 - Manual (Page 66)

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15.1.4 1 Vpp measuring systems with SSI interface and HTL supply voltage
For the software version 10 applies:
Same functions as 1 Vpp measuring systems with EnDat interface (see section: 1 Vpp measuring systems
with EnDat interface) To be able to set the power supply for HTL encoders, these encoders must be
operated with the parameter setting P9 = "PROG. SSI". The additional parameter functions of the
programmable SSI interface must not be used for these encoders! Switching to HTL encoder supply is
described in the section Switching the encoder supply to HTL.
The sensor connection can be set in the parameter P10. Recommended setting: "AUTO" (see also section
Parameter P10 "Sensor connection" with programmable SSI encoders).
Caution:
To avoid malfunctions or destruction of the encoder the offered programming features must not be
used for this HTL application!
As of the software version 11 applies:
Same functions as 1Vpp measuring systems with EnDat interface (see section 1Vpp measuring systems
with EnDat interface).
These measuring systems are operated with the parameter setting P9 = "SSI/EnDat". The additional
functions of the programmable SSI interface are not available with these measuring systems and therefore
not offered by the software. Switching to HTL encoder supply is described in the section Switching the
encoder supply to HTL.
15.1.5 1 Vpp measuring systems with programmable SSI interface
Same functions as 1Vpp measuring systems with EnDat interface (see section 1Vpp measuring systems
with EnDat interface).
In addition these measuring systems offer the following characteristic features:
1. The following functions can be programmed:
PIN 2 (IN): Changing the direction of rotation by applying Up
PIN 5 (IN): Preset 1 – any desired position determined via the programming software
can be loaded by applying Up for > 1ms.
PIN 6 (IN): Preset 2 – any desired position determined via the programming software
can be loaded by applying Up for > 1ms.
2. Additional serial interface instead of the sensor lines for further programming functions.
3. HTL encoder supply (10V-30V)
4. General encoder interference signal at PIN3.
The PWM displays this interference signal as "/UaS2" in the LC display instead of the "REF display"
(possible as of interface board Id.No. 312186-01 with hardware index b). The "/UaS2" is not the same as the
"/UaS" interference signal. The "/UaS2" signal is generated on the interface board, the "/UaS" signal by the
encoder and fed to the PWM via PIN3.
In the setting "programmable SSI" the interface board is prepared for the additional functions. In order to
enable the interface board to execute these functions, the related menu must be activated through a key
combination.
For reasons of safety the HTL supply for the programmable SSI measuring systems must be switched on by
the operator in the additional menu. If HTL supply is activated, the sensor lines of the measuring system are
connected to the subsequent electronics through the PWM8. Thus, the additional serial interface is
operative.
If the measuring system is to be powered from an external power source (= U_MSYS EXT) with the HTL
supply switched on, the parameter "P2 = U_MSYS EXTERN“ must be set to "FROM CUSTOMER“. The
PWM8 automatically activates the parameter P2. The parameter option
"P2 = FLOATING" is not possible!