Retrofitting a 1986 Maho MH400E

Thanks for the inputs. In the HAL.Oszi screen shots, what are the Red line at the top, the purple in the middle and the blue line near the bottom please? The legend is not legible.
I am not sure if I understand what the HAL-Oszi is displaying. Is it the open/closed status of the gearbox feedback swtiches in response to the individual motor relays being activated, with the file name giving the selected motor and direction? eg m_r.png = Midrange motor (Mittelstufe) relays powered and with the change direction (Drehrichtung Umkehr) in direction RH? What is l_r.png?

The 400E gearbox schematic seems similar, although differently drawn to the MH700 you sent. I'll have to trace through in more detail to see if they are significantly different. I noted that my schematic has an extra "Start" relay in the gearbox control circuit which the MH 700 didn't have.

The three 100ohm 20W variable resisters are located at the top of the 28A1 Relaisplatine 11R1-11R3 on mine.

To try and keep all the relevant information together, here is the manual positioning of the gear shifter positions with the resulting spindle speeds.

I appreciate your offer to share the code you have already written for this system. It seems that the topic of retrofitting MAHO's comes up often on all the forums, and some have successfully integrated the gearbox control into LinuxCNC, but the knowledge is not easily accessible in one thread or location. I tried searching the IRC archive, but it also have found little info on MAHO gearbox control.
Mark

A basic question, if you can do the complicated control of this gearbox with it's 8 relays and 12 feedback switches plus timing and twiching the spindle directly in the HAL, what is classic ladder used for?
Mark

For some people graphical ladder logic is easier to program than hal logic, especially when it gets complicated. There isn't much (if anything) that can be done in Classicladder, that can't be done just in Hal.

Ladder is rather better for sequences than HAL. It is also a lot easier for experienced ladder programmers.

But I don't know Ladder, so always end up using HAL (often with custom components)

your start relais seems to be for switching to low speed for the alternating left/right turning. On the Mh700 this is done with an 70V transformer output.

Hal Oszi:
I Used Hal Oszi with an input card to record what happens when the original PLC is switching gears, my real Oszi has only 4 Channels.

the png are named as the movements : L_R = Position left to Pos right switching.

links,rechts,mitte,richtung are the four cams of on transmission stage (left,right,center,an one switch witch tells the siemens plc, in which direction the motors turns last and if it has to start in opposite direction) If you start in wrong direction the motors has not enough power to lock the gear in. Also its important from the timing that the gear motor starts with the right direction from the main spindle turning.



K7Richtung, K3 Motor, Wahlmitte, Bremse are the Outputs of the PLC to the Relais. (direction Motor, Motor Power, the relais witch enable the center switch, Spindle Brake)

there have been some solutions in the past, but only for the 2 stage Transmission with Frequency driven Spindle motor. This Transmission has only 2 Positions (Left/right) per stage, without the hole Center Position part.

My component is finished an i will share it. the things i thought which were unready have to be in the control panel part.
I only need a little bit time, to do some coments and optic....

I have not used ladder (hating...) or special hal programming.
Its an real time C component.