Hello,
If you have both motor with encoder, you can get the position exactly of you final shaft, the limit switch should be used in order to calibrate home position, once calibration is used only for safety issues, you can work with control positions, torque control, control speed or three of them, but taking care the position in parameter H511 in motor with rotation CW and CCW, with main motor that has only CW rotation, you can use the function module if is necessary.
First, you need both Movidrives connected by Sbus, in order share positions like an master/slave relation ship.
Second, In parameters you have to enable
Parameter.
960 Function Module -CW or CCW
961 Modulo Numerator - XXXXX
962 Modulo Demonimator - XXXXX
those parameters 961 and 962, is according your gearbox ratio, P961/P962= i (Ratio to your Gearbox) but exactly, you can get it from your sales SEW, or numbers of teeth gearbox inside.
You should make a program in Ipos in order to calibrate and once after that it can work per weeks and months without calibration and witout lost positions.
Additional questions, who controlled the position now?, how is the connection with PLC and Movidrive, (Analog?, by Bus?).
Are you able to make Ipos program? you can use it in your PLC if you have Bus connection between PLC and Movidrive, but I prefer use only movidrive.
I already made programs like that,so If you want I can send you some examples.
Read about this manual
http://download.sew-eurodrive.com/download/pdf/11320419.pdf
Regards