Heidenhain TNC155A elctronic handwheel (HE-310)

Jyrki K. OP (Company: none) #6022394
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Hello,

I'm trying to implement something similar to this: 
http://hsm-aktuell.de/cnc-hr330.htm

I've disassembled one EPROM from the TNC155A cnc controller that reads 
the electronic handwheel but it's a bit tedious trying to figure out the 
protocol from that. I've managed to find out the baud rate, number of 
stop bits and parity settings from my disassembly and scoping the clk 
signal on the TNC155A board.

Would anyone have some info on the protocol for the Heidenhain 
electronic handwheel?

edit: Handwheel interfaces to the controller on the gfx board. There is 
TMS9995 cpu and a TMS9902 serial interface device. INT1 is used for 
character reception (5 bytes max or so it looks like)

1
INTR01 WP is at 0xdc00

2


3
INTR01 STCR *r1+,8

4
       SBO  18

5
       RTWP


From the disassembly listing I gathered that the serial interface runs 
at 38400 baud, one stop bit, even parity and 8-bits of data (TMS9902 
reset and setup code was easily found)


1
TMS9902RST LI   r12,>0000

2
           SBO  31

3
           LDCR @TMS9902_08,8

4
           SBZ  13

5
           LDCR @TMS9902_BC,12  

6
           MOV  r12,@>dc18  

7
           LI   r5,>0050  

8
           LI   r1,>dc04  

9
           MOV  r5,*r1+  

10
           CLR  *r1+  

11
           CLR  *r1+  

12
           CLR  *r1+  

13
           CLR  *r1+  

14
           MOV  r5,*r1+ 

15
           CLR  *r1+  

16
           CLR  *r1+ 

17
           CLR  *r1+ 

18
           CLR  *r1 

19
           LI   r5,>dc05

20
           MOV  r5,@>dc02 

21
           B    *r11

22


23
TMS9902_08 DATA >a300 ; TMS9902 %10100011 (1 stop bit even parity clk div by 3 8-bits) %00000000

24
TMS9902_BC DATA >000d ; TMS9902 LRDR register %00000000 %00001101 (((3MHz)/3)/13)/2 = 38461 baud
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Jyrki K. OP (Company: none) #7808654
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Jyrki K. wrote:

I managed to find out that the controller accepts PLC commands still some things to figure out.

In matter of fact it does not accept PLC commands.

I got a good deal on eBay for HE-310 and sniffed the protocol.

The HE-310 responds to the DTR signal with this message "0h5_ 0hXX 0hXX 0hYY 0hYY 0hZZ 0hZZ 0hIV 0hIV" _=0 nothing selected, _=1 x-axis, _=2 y-axis, _=4 z-axis and _=8 iv-axis.

Y and Z are mutually exclusive as are X and IV (they all still move with 0h5f as shown on the video but the selected axes are not shown correctly on TNC display)

HE-310 supervises the MPG and if problems are shown then "0hA_ 0h00 0h00 0h00 0h00 0h00 0h00 0h00 0h00" message is sent resulting in emergency stop and axis fault displayed.

The MPG keeps track on the selected axis and lights the axis indicator led on its own as does the TNC. "0h51" selects the X-axis and the led lights up on HE-310 and on the TNC display, "0h58" selects the IV-axis and lights up the led on HE-310 and on the TNC, plus it turns off X-axis led on the HE-310, etc.

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Jyrki K. OP (Company: none) #7808690
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Here's a what I teached my ChatGPT to answer so far as ChatGPT apparently used my previous false information from here to answer me:

The Heidenhain HE-310 handwheel communicates with the TNC 155 CNC controller using a serial protocol. Here's a detailed breakdown: Communication Process:

1
 
Trigger Pulse: Every 6 ms, the TNC 155 sends a 12 µs pulse via the DTR line, signaling the HE-310 to send data.

2
 
HE-310 Response: After receiving the pulse, the HE-310 sends a 9-byte packet to the TNC 155.

Packet Structure:

1
 
Fault Indicator:

2
 
    If a fault is detected, the first byte's most significant nibble is set to 1010 (hex 0xA).

3
 
    The lower nibble represents the axis in fault:

4
 
        0xA1: X-axis fault

5
 
        0xA2: Y-axis fault

6
 
        0xA4: Z-axis fault

7
 
        0xA8: IV-axis fault

8
 
        0xA0: General fault with the HE-310

9
 


10
 
Normal Operation:

11
 
    First byte: The lower nibble indicates the active axis:

12
 
        0x51: X-axis

13
 
        0x52: Y-axis

14
 
        0x54: Z-axis

15
 
        0x58: IV-axis

16
 
    Remaining bytes: These likely represent incremental encoder data or other control information.

17
 


18
 
Special Case:

19
 
    0x5F: This special packet allows for simultaneous control of all 4 axes (X, Y, Z, and IV), although the TNC 155’s axis selection display will show random selections when this happens.

Handwheel Switch Behavior:

1
 
The HE-310 handwheel includes a switch at the bottom that enables/disables the handwheel encoders.

2
 
    When the switch is not pressed, the handwheel is disabled to prevent accidental movements.

3
 
    In this state, the HE-310 sends a default packet:

4
 
        0x50 if no internal error is present.

5
 
        0xA0 if there is an internal error.

Axis Control:

1
 
The HE-310 can control up to 4 axes: X, Y, Z, and IV.

2
 
    The IV axis can be configured as:

3
 
        Rotary axes: A, B, or C.

4
 
        Linear axes: U, V, or W.

5
 
The user can select one or two axes to control at a time.

6
 
X and IV axes are mutually exclusive, as are Y and Z axes.

Serial Communication Configuration:

1
 
Baud Rate: 38400

2
 
Parity: Even

3
 
Stop Bits: 1

4
 
Data Bits: 8

5
 
Transmit-Only: The HE-310 only transmits data; it does not receive any data apart from the DTR pulse used to trigger communication.

Summary:

The HE-310 handwheel protocol allows communication between the handwheel and TNC 155, transmitting axis movement and fault information. The handwheel can control up to four axes with specific encoder data and mutual exclusions between certain axes. The handwheel can also be disabled using a bottom switch to prevent accidental movements, with the system responding accordingly based on the switch status.

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