Fig. 2-99 4720 – Encoder interface, receive signals, encoders 1 ... 2
- 4720 -
Function diagram
87654321
fp_4720_97_55.vsd
Encoder evaluation
SINAMICS G120D
12.12.2012 V4.6
Encoder interface, receive signals, encoders 1 ... 2
0
r0487[n-1]
Geb Gn_STW
1 0 1
0 0
0 0
1
00
0
1
2
3 4
3
2
1
Bit
<1>
5
7
8...12
13
14
15
1
<3>
6
<4>
<1>
PROFIdrive-Bit
4
<5>
Enc Gn_STW S_src
(0)
p0480 [n-1]
Control word for encoder n (n = 1 or 2)
Selects the function to be activated (with bit value = 1)
Function
no.
Function for bit 7 = 0
(search for reference mark)
Function for bit 7 = 1
(flying measurement)
Reference mark
Reference mark
Reference mark
Reference mark
Measuring probe
Measuring probe
1
2
3
4
Measuring probe
Measuring probe
1
2
3
4
Start/stop/read selected function
Interrupt function
Reserved
Activate selected function
No function
Mode of the function to be activated
1 = flying measurement
0 = Search for reference mark (zero mark or BERO)
1 = Request cyclic transfer of the absolute position value in
Gn_XIST2
(e.g. EQN absolute track; acknowledgment in Gn_ZSW bit 13)
1 = Request parking encoder (handshake with Gn_ZSW bit 14)
= acknowledge encoder fault (located in Gn_ZSW, bit 15;
Handshake with Gn_ZSW bit 11)
id controller
Bits 0...13 control what is transferred in
Gn_XIST 2.
There are 3 alternatives:
- Bit 7 = 0: Position actual value at the reference
mark <2>
- Bit 7 = 1: Position actual value when the
measuring probe edge is received <2>
- Bit 13 = 1:Cyclic absolute position value from
absolute encoder
Index [n-1] --> encoder n
Index [0] --> encoder 1
Index [1] --> encoder 2
Actual position values are read out from Gn.XIST2 using a handshake
procedure. e.g.: Read position value(s) at reference mark(s)
1. Set r0487.[0-3] according to the function to be activated.
2. Set r0487.4 (activate function)
3. Reset all bits from r0487.[0-4] to 0.
4. r0481[0-3] must be active depending on the activated function.
5. Overtravel zero mark(s) until all bits in r0481.[0-3] are reset to 0.
6. Select r0487.[0-3] individually and activate with r0487.5 until r0481.[4-7]
is equal
to 1 and read out the position values in r0483.
7. Reset all bits, starting with r0487.5 followed by r0487.[0-3].
Select function 1 [Bit 3...0]
("search for reference mark 1")
000 000
001
000 010
0001
Start function [Bit 6...4]
Function active [Gn_ZSW Bit 0]
Actual value save at the
reference mark
Read generated value [Bit 6...4]
Position actual value at reference
mark 1 in Gn_XIST2
Value from function 1 available
[Gn_ZSW Bit 4]
Further reference marks can be read out according to PROFIdrive profile.
The bits are processed with the following priority sequence (highest priority
--> lowest priority bit): Bit 14 --> Bit 15 --> Bit 4-7 --> Bit 12 --> Bit 13.
The checkback signal is provided in Gn_ZSW bit 14, but the encoder is not
actually parked.
If the "position module" function module is activated, the
interconnection is established via r2520[0]...[1] from [4010.8].
If a standard telegram (PROFIdrive) is selected, the interconnection is
performed according to the specifications of the standard telegrams [2420].
<1>
<2>
<3>
<4>
<5>
To the position sensing, encoder n
[4704.3]
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