Siemens SINUMERIK 840C - Manual (Page 734)

10 Axis and Spindle Installation 11.92
10.4.5 Distance-coded reference marks
The following control loops must be used for processing distance coded reference marks:
• SPC control loop.
Measuring systems with rectangular and sinusoidal output signals (currents) can be
connected to a SPC.
Where measuring systems have sinusoidal output signals, EXE submodules must be
inserted into the module.
• HMS control loop.
As standard, this board is only used for encoders producing unconditioned voltage signals.
Encoders producing unconditioned current signals can also be connected if, instead of the
shorting plug, an I/V hybrid is inserted in the relevant jumper sockets (U23, U17, U12 for
axes 1,2 and 3). (no EXE submodules).
For reasons of interference immunity and precision, the unconditioned current signal
encoder can only be connected directly if the cable is no longer than 18 m. If the cable is
longer, the unconditioned current signals must be converted to unconditioned voltage
signals of specifed amplitude in an external converter positioned close to the encoder.
Encoder with voltage signals
(800mV to 180 ohms) Encoder with current
signals (5.5
µ A)
Axis 1 Shorting plug (X23) I/V hybrid (U23)
Axis 2 Shorting plug (X17) I/V hybrid (U17)
Axis 3 Shorting plug (X12) I/V hybrid (U12)
The shorting plug (minimum 12-pin) and the I/V hybrid (20-way) are both connected to start at
pin 1.
X . .
11 –
12 –
13 –
14 –
15 –
16 –
17 –
18 –
19 –
20 – – 10
– 9
– 8
– 7
– 6
– 5
– 4
– 3
– 2
– 1
U . .
Note:
During reference point approach, the axis must be brought to rest within the range covered by
the (linear) scale after crossing two adjoining reference marks.
10–44 © Siemens AG 1992 All Rights Reserved 6FC5197- AA50
SINUMERIK 840C (IA)