Renishaw RPI30 User manual

User’s guide
F-9926-0018-01-B
RPI30 parallel interface

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INACCURACIES IN THIS DOCUMENT.
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registered trademarks of Renishaw plc in the UK and other countries.
apply innovation is a trademark of Renishaw plc.
All other brand names and product names used in this document are
trade names, service marks, trademarks, or registered trademarks of
their respective owners.
Care of equipment
Renishaw part no: F-9926-0018-01-B
Issued: 05 2020
The RPI30 parallel interface contains precision electronic components.
Avoid exposure to moisture. Remove power before connecting,
disconnecting, handling or changing switch settings.
WARNING: Use correct handling techniques when
touching any of the RPI30 assemblies to prevent
damage from electrostatic discharge (ESD).
Changes to Renishaw products
Renishaw plc reserves the right to improve, change or modify its
products and documentation without incurring any obligation to make
changes to Renishaw equipment previously sold or distributed.
Warranty
Renishaw plc warrants its equipment provided that it is installed exactly
as dened in associated Renishaw documentation.

Safety
It is the responsibility of the manufacturer and/or encoder system
installation authority to ensure that, in safety critical applications of the
RPI30 parallel interface, any form of signal deviation from the limits
of the receiving electronics, howsoever caused, shall not cause the
machine to become unsafe. It is also their responsibility to ensure that
the end user is made aware of any hazards involved in the operation
of their machine, including those mentioned in Renishaw product
documentation, and to ensure that adequate guards and safety
interlocks are provided.
When using the RPI30 as part of a positioning system on machines,
beware of pinch and/or crush hazards that can be created, depending
on how and where the equipment is installed.
Further information on safety is contained in Appendix B.
The RPI30 has been designed for use with an RLE laser encoder only.
Its use is not supported with other encoder systems.

FCC notice
This device complies with part 15 of the FCC Rules. Operation is subject
to the following two conditions: (1) This device may not cause harmful
interference and (2) this device must accept any interference received,
including interference that may cause undesired operation.
This equipment has been tested and found to comply with the limits
for a Class A digital device, pursuant to part 15 of the FCC rules.
These limits are designed to provide reasonable protection against
harmful interference when the equipment is operated in a commercial
environment. This equipment generates, uses, and can radiate radio
frequency energy and, if not installed and used in accordance with
the instruction manual, may cause harmful interference to radio
communications. Operation of this equipment in a residential area
is likely to cause harmful interference in which case the user will be
required to correct the interference at his own expense.
The user is cautioned that any changes or modications not expressly
approved by Renishaw plc or authorised representative could void the
user’s authority to operate the equipment.
EC compliance
Renishaw plc declares that the RPI30 parallel interface complies with
the applicable directives, standards and regulations. A copy of the full
EC Declaration of Conformity is available at the following address:
www.renishaw.com/RLECE
WEEE
The use of this symbol on Renishaw products and/or
accompanying documentation indicates that the product
should not be mixed with general household waste
upon disposal. It is the responsibility of the end user to
dispose of this product at a designated collection point
for waste electrical and electronic equipment (WEEE)
to enable reuse or recycling. Correct disposal of this
product will help to save valuable resources and prevent
potential negative effects on the environment. For more
information, please contact your local waste disposal
service or Renishaw distributor.
Packing material information
Compliant with EC directive 2011/65/EU (RoHS)
Packaging
component
Material 94/62/EC
code
94/62/EC
number
Metalised bag Aluminium foil/PETP laminate C/PET 90
Cartons Cardboard - 70% recycled
content
PA P 20
Bubble bags Low density polyethylene LDPE 4
REACH regulation
Information required by Article 33(1) of Regulation (EC) No. 1907/2006
(“REACH”) relating to products containing substances of very high
concern (SVHCs) is available at:
www.renishaw.com/REACH
RoHS compliance
Compliant with EC directive 2011/65/EU (RoHS)
c

1
Contents
Contents
1 System overview.............................................................. 2
2 Installation........................................................................ 3
2.1 Handling precautions....................................... 3
2.2 Mounting and xing ......................................... 3
2.3 Analogue quadrature interface ........................ 4
2.4 Analogue feed through ................................... 6
2.5 Diagnostics ..................................................... 6
2.6 Parallel interface .............................................. 7
3 Conguration ................................................................... 9
3.1 RLE set-up – dip switches............................... 9
3.2 RPI30 set-up ................................................ 10
3.3 /Error line....................................................... 11
3.4 LED indicator................................................. 11
4 Communication over the parallel bus.......................... 12
4.1 Parallel bus ................................................... 12
4.2 Functionality .................................................. 13
4.3 Timing diagram.............................................. 16
AppendixA–Specication .................................................. 18
Appendix B – Safety information ......................................... 19
Appendix C ............................................................................ 21
1 SPI programming guide ........................................... 21
1.1 Timing............................................................ 21
1.2 Command makeup ........................................ 21
2 Registers ................................................................... 22
2.1 Register map ................................................. 22
2.2 Version (Block = 0) ........................................ 23
2.3 ADC (Block = 1)............................................. 23
2.4 Interpolator (Block = 2).................................. 25
2.5 Position (Block = 3)........................................ 25
2.6 Output control (Block = 4).............................. 25
2.7 Reset / Errors (Block = 5) .............................. 27
2.8 EEPROM (Block = 6)..................................... 28
2.9 Lissajous correction status (Block = 8).......... 29
2.10 Lissajous correction control (Block = 9)......... 30
2.11 Data logger (Block = 10)................................ 31
Appendix D ............................................................................ 33
1 Diagnostics link ........................................................ 33
1.1 Physical ......................................................... 33
1.2 Format ........................................................... 33
2 Registers ................................................................... 33
2.1 Differences to SPI interface ........................... 33
2.2 Diagnostics (Block = 15)................................ 34
3 Streaming data .......................................................... 35
3.1 Packet format................................................. 35
4 Download datalogger RAM ...................................... 36

2System overview
1 System overview
The RPI30 converts 1 Vpp analogue quadrature signals from an RLE
laser interferometer encoder system into a position reading, which is
available over a parallel bus. The RPI30 interface includes active
Sub Divisional Error (SDE) correction, to further reduce the effect of
errors within the motion control system. This is applied by actively
updating the DC offset and AC mismatch when the system is in use to
achieve the highest performance.
Additionally the RPI30 has an separate diagnostics connection to allow
diagnostics information to be downloaded and analysed remotely.
The RPI30 gives an output of both axis position and status over a
LVTTL (3.0 V) compatible bus. The position is available as a 36-bit two’s
complement word, with a choice of least signicant bit (LSB) resolution.
The status information includes the signal strength and error ags.
Part numbers
The following saleable part number is available:
• A-9926-0700 RPI30 fast parallel interface
In addition, the mating half of the RPI30 parallel bus connectors can
also be supplied by Renishaw. The saleable part number is:
• A-9904-2256 RPI connector 0°
For information on the connector please refer to Section 2.
RPI30 fast parallel interface

3
2 Installation
2.1 Handling precautions
WARNING: Use correct handling techniques when touching any
of the RPI30 assemblies to prevent damage from ESD.
2.2 Mountingandxing
The RPI30 can be supported using the four mounting holes (A, B, C
and D) which are suitable for M3 screws. The position of the holes are
shown within diagram opposite. All dimensions are in millimetres.
Note: Holes A and B are electrically connected to chassis ground.
Holes C and D are unconnected.
Note: Mounting screws should not exceed a maximum torque
of 0.6 nm.
!
110
101
72
10 95
62
31
36
RPI30 fast parallel interface dimensions
A
C
D
B
Installation

4
2.3 Analogue quadrature interface
The RPI30 accepts the nominal 1 Vpp analogue quadrature from the
RLE. Signal termination is contained within the RPI30 itself. There is no
need for any other termination to be used.
Cabling
The choice of cables for this application is very important. A cable with
individually screened twisted pairs is recommended. An example of a
suitable cable is the Belden 8164 cable. The maximum recommended
cable length is 10 m. The signals should be wired as shown in the table
below:
Signal Function
1st pair Sine and /Sine
2nd pair Cosine and /Cosine
3rd pair Error and /Error
Individual screens 0 V (both ends)
Outer screen Case/shell (both ends)
Signal wiring between RLE and RPI30
!
!
Installation
WARNING: It is essential that the error line inputs are connected
so that the RPI30 can determine if any errors have occurred in
the RLE system. If the analogue quadrature is incorrectly wired,
the system may still work but may move distances and at speeds
that are not expected and may move in the opposite direction to that
expected. If a voltage exceeding ±7 V is applied on any of the signals,
damage to the unit can occur.
WARNING: Care should be taken to ensure that individual signal
wires do not short. It is advised that all joints are sleeved. If input
signal wires short, the position output will be unreliable and the error
signal may not work reliably.

5
Analogue quadrature input mating connector
(15 way D-type male connector)
Installation
Connector pin out
The analogue quadrature input connector pin out is shown in the table
below. All pins are protected to ±7 V. The connector on the RPI30 is a
15way female D-type. The diagram opposite shows the mating D-type
connector.
Pin number Function
10 V
2 –
3 Error
4 –
5 Sine
6 Cosine
7 –
8 –
9 –
10 /Error
11 –
12 /Sine
13 /Cosine
14 –
15 –
Shell Chassis ground
Analogue quadrature input (15 way D-type male)

6Installation
2.4 Analogue feed through
The analogue quadrature and error inputs are buffered and available
on an 8-way picoblade connector. These are copies of the input signals
and do not have any SDE correction appled or RPI30 errors included.
The analogue quadrature signals should be terminated with 120ohm.
Pin number Function
1 /Sine
2 Sine
3 0V
4 /Cosine
5 Cosine
6 0V
7 Error
8 /Error
Analogue feedthrough connector (8-way picoblade)
2.5 Diagnostics
A full duplex RS422 UART connection is provided to access the
diagnostic and control registers in addition to the normal SPI interface.
Full details can be found in Appendix D.
Pin number Function
1 Rx +
2 Rx -
3 0v
4 0v
5 Tx +
6 Tx -
Diagnostics connector (6-way picobade)
1 2 3 4 5 6 7 8 1 2 3 4 5 6

7
2.6 Parallel interface
Connector
The correct mating connectors for the RPI30 parallel bus are the JAE
TX24 60R family of connectors. These may be supplied by Renishaw or
direct from JAE.
Pin Label Pin Label Pin Label Pin Label
15 V 16 DTA26 31 5 V 46 DTA19
20 V 17 DTA25 32 0 V 47 DTA18
3 DTA15 18 DTA24 33 DTA7 48 DTA17
4 DTA14 19 DTA33 34 DTA6 49 DTA16
5 DTA13 20 DTA32 35 DTA5 50 DTA35
6 DTA12 21 DTA34 36 DTA4 51 Reserved
7 DTA11 22 Reserved 37 DTA3 52 Reserved
8 DTA10 23 Reserved 38 DTA2 53 SDI
9 DTA9 24 ADD4 39 DTA1 54 SDO
10 DTA8 25 ADD3 40 DTA0 55 SCLK
11 DTA31 26 ADD2 41 DTA23 56 CSB
12 DTA30 27 ADD1 42 DTA22 57 Reserved
13 DTA29 28 ADD0 43 DTA21 58 /Enable
14 /Error (O/C) 29 0 V 44 DTA20 59 0 V
15 DTA27 30 5 V 45 DTA28 60 5 V
RPI30 parallel bus connector pin out
Installation

8
Description Renishaw part number JAE part number
RPI mating
0° connector A-9904-2256 TX24-60R-6ST-H1E
Part number for JAE connector
Note: using RPI mating 0º connector, A-9904-2256,
separation between boards = 12 mm
RPI30 parallel bus mating connector
Other separations can be achieved using other receptacles.
For detailed information on the connectors, please visit the JAE web site
at: www.jae-connector.com
Installation

9
3 Conguration
3.1 RLE set-up – dip switches
If the RPI30 is being used with an RLE system, care should be taken
setting the RLE conguration switches correctly.
RLE switch
number
Status Details
5 DOWN Analogue quadrature output
11 DOWN RLE does not tri-state the quadrature on error
12 UP Set to UP, unless ne digital quadrature
output from the RLE is also required (in
addition to the RPI30 parallel output)
13 DOWN RLE does not latch errors, the RPI30 will
latch any errors agged
RLE dip switch settings
Note: The RLE axis direction reversal switches 6 and 7 only affect the
direction of the digital quadrature from the RLE and not the analogue
quadrature.
Note: Make sure the parity switch is set in accordance with the RLE
manual (M-5225-0568)
Note: The RLE will ag an error when the measurement velocity
reaches a level at which the required output rate of the digital
quadrature exceeds the digital bandwidth limit of the RLE. The digital
bandwidth limit depends on the digital quadrature resolution and
maximum output bandwidth selected with the RLE DIP switches. The
digital quadrature resolution and the digital output bandwidth should be
selected so that the RLE measurement velocity limit is sufcient for the
application. It is therefore recommended that ne quadrature is disabled
by setting RLE switch number 12 UP.
For further information on the RLE front panel switches refer to the RLE
manual (M-5225-0568).
Conguration

10
3.2 RPI30 set-up
The settings for the parallel interface and lissajous correction are
accessible over the SPI interface and also the diagnostics UART
interface. Power on settings are stored on EEPROM and can be
updated via either interface.
Setting Factory default
Parallel bus Address 1
Direction 0 – Forward
Resolution 0 – 38.6 pm
Lissajous correction Enable 127 – all disabled
Sample length 1000 – 1 ms
Min quads 8
Max quads 5000
Offset lter length 3 – 14 bit
AC mismatch lter length 3 – 14 bit
User calibration Sine / cosine offset 0
Sine / cosine gain 43690 – x1.33
Factory defaults for settings stored in EEPROM
The SPI and UART interfaces also allow access to a variety of additional
information including
• RPI30 version
• ADC data
• Position data
• Lissajous correction status
• Independent resetting of errors and position
Full details can be found in Appendix C for the SPI interface and
Appendix D for the UART.
Conguration

11
Conguration
3.3 /Error line
The parallel bus includes a /error line which is active low. The /error line
indicates if any errors have occurred with either the RLE or the RPI30.
The /error line is latched if an error occurs and must be cleared by a
reset. The /error line is an open collector output and should be pulled up
to the controller IO voltage with a resistor as shown below.
Maximum
Voltage 30 V
Current 45 mA
/Error maximum ratings
Open collector error output wiring
WARNING: The open collector /error line is not a fail-safe method
and therefore additional safety precautions must be taken in
safety critical closed loop applications. The /error line must be
continually monitored and the motion system must be stopped if it is
asserted.
3.4 LED indicator
An LED indicates the status of the RPI30.
LED Status
Red RPI30 powered but in error condition
Green RPI30 powered and no error
Amber RPI30 powered and in warning state
LED status indicator
!
RPI30
R
Controller
VIO (max 30 V)
120 Ω
0 V

12
4 Communication over the parallel
bus
High speed communication with the RPI30 is performed over the
parallel bus.
Five functions may be performed over the parallel bus:
1. Latching all of the RPI30 position and status data simultaneously
2. Reading of the latched positions
3. Reading of the latched status information
4. Resetting of the position and clearing of all errors
5. Enabling test information onto the RPI30 parallel bus
All data must be latched before it is read.
4.1 Parallel bus
The parallel bus contains a 5-bit address bus, a 36-bit data bus, /enable
line and /error line.
Address bus
The top three lines of the address bus are used to choose which RPI30
unit to communicate with. Each RPI30 unit has a unique base address,
selected over the SPI interface, as detailed in Section 3.2. Base address
0 is reserved for simultaneous communication with all RPI30 units on
the bus.
The bottom two lines of the address bus are used to dene the required
function. The address bus functionality is described in the table on page 13.
Data bus
The RPI30 can be requested to put either position or status data on the
data bus. The position data is a 36-bit word with DTA0 as the LSB and
DTA35 as the MSB. The status information is detailed in the table on
page 13.
/Enable
The /enable line has two functions. The rst is to latch or reset position
and status data. This is initiated by a falling edge of the /enable signal.
Secondly, it is used to enable data onto the bus. Refer to table on
page 14.
/Error
The /error line indicates when a fault has occurred in the measurement
system. It is described in detail in Section 3.3 on page 11.
Communication over the parallel bus

13
4.2 Functionality
Five functions may be performed over the parallel bus.
These are:
1. Resetting the position and error status of the RPI30
2. Latching the position and status reading of all
RPI30s simultaneously
3. Transferring latched position information onto the
RPI30 parallel data bus
4. Transferring latched status information onto the
RPI30 parallel bus
5. Transferring test information onto the RPI30 parallel
bus
The required function is chosen by selecting the correct
register. The functionality is shown in the following table.
RPI30 Address location (bit) Register Function
4 3 2 1 0
All 0 0 0
0 0 1 Latch all RPI30 units
0 1 2 Reserved
1 0 3 Reset all RPI30 units
1 1 4 Reserved
Unit 1 0 0 1
0 0 1 Read RPI30 unit 1 position
0 1 2 Read RPI30 unit 1 status
1 0 3 RPI30 unit 1 reset
1 1 4 Read RPI30 unit 1 test information
Unit 2 0 1 0
0 0 1 Read RPI30 unit 2 position
0 1 2 Read RPI30 unit 2 status
1 0 3 RPI30 unit 2 reset
1 1 4 Read RPI30 unit 2 test information
Unit 7 1 1 1
0 0 1 Read RPI30 unit 7 position
0 1 2 Read RPI30 unit 7 status
1 0 3 RPI30 unit 7 reset
1 1 4 Read RPI30 unit 7 test information
RPI30 address bus functionality
Communication over the parallel bus

14
Reset
Register 3 is used to reset the RPI30. If there are no errors currently
active in the system, the /error line is reset, any latched error ags
are cleared and the position output is set to zero. All RPI30s may
be simultaneously reset by addressing register 3 of base address 0
and taking the /enable line low. An individual RPI30 may be reset by
addressing register 3 of its base address and taking the /enable line low.
Latch data
Register 1 of base address 0 is used to latch both the position data and
the status data of all the RPI30s simultaneously.
Enable position data
Register 1 of a particular RPI30 unit’s base address holds the latched
position data. If this register is selected on the address bus, then
position information is placed on the data bus after the /enable line
is taken low. The position output is represented in two’s complement
format as shown below.
MSN LSN Position
7 F F F F F F F F (235 -1 × UOR)
0 0 0 0 0 0 0 0 2 2 × UOR
0 0 0 0 0 0 0 0 1 1 × UOR
0 0 0 0 0 0 0 0 0 0 × UOR
F F F F F F F F F -1 × UOR
F F F F F F F F F -2 × UOR
8 0 0 0 0 0 0 0 0 -235 × UOR
Position output in two’s complement format
UOR = unit of resolution of LSB as set by control register 4-3
MSN = most signicant nibble
LSN = least signicant nibble
Communication over the parallel bus

15
Enable status data
Register 2 of a particular RPI30 unit holds the latched status information. If
this register is selected on the address bus, the status information is placed
on the data bus after the /enable line is taken low. Information contained in
the status register is detailed in the table below.
Bits Function Comment
0-9 Analogue quadrature
sample – cosine
This is the digitised input value of
the cosine signal *
10-19 Analogue quadrature
sample – sine
This is the digitised input value of
the sine signal *
20-27 Signal level Amplitude of input quadrature
(0 to FF where FF=115% signal
strength) *
28 Encoder error (1 = error) Error agged by encoder system
29 Overspeed error (1 = error) **
30 Beam break error (1 = error) Input quadrature amplitude too
low (<12.5%)
31 Bus setting changed A setting for the parallel bus has
changed.
32-33 Resolution setting 00 = 38.6 pm, 07 = 77.2 pm,
10 = 104.4 pm, 11 = 308.8 pm
34 Direction setting (0 = FWD, 1 = REV)
35 EEPROM conguration
error
Conguration EEPROM CRC
failed
Status information
* Bits 0, 10, 20 are the LSBs of the digitised cosine, sine and signal level
values respectively.
** An overspeed error is agged when the input analogue quadrature rate
exceeds the processing capability of the RPI30.
Enable test data
Register 4 of a particular RPI30 unit holds test information which
can be used for checking the data bus for open and short circuits
and failed drivers.
Note: The test information in register 4 may be used to verify
the presence of all expected RPI30s at power-up and before
engaging drives.
Communication over the parallel bus

16
4.3 Timing diagram
A timing diagram for a two-axis position read is shown below. The read
consists of three separate stages.
1. Latch data by asserting /enable with the address but set to 00000b
(base address 0, register 1) *
2. Read in position data from axis 1 by taking /enable low whilst the
address bus is set to 00100b (base address 1, register 1) **
3. Read in position data from axis 2 by taking /enable low whilst the
address bus is set to 01000b (base address 2, register 1) **
The same timing sequence should be used to reset an RPI30.
RPI30 parallel bus timing diagram
Tsu
To e
Thd Tsu Thd
TvzTzv
Tsu Thd
Sample Sin Cos
Address Bus
/Enable
Data Bus
Address Bus
/Enable
Tpd To eTe h
Tr e
Te r
To e
Reset
Any Any
00100b
Axis 1 data Axis 2 data
00000b 01000b
Te h
* This will replace any previously latched data.
** This will not clear the latched position. It can be read again if necessary.
Communication over the parallel bus