does it works for closed loop operation ?  --->

http://www.rogersmachine.net/encoderinfo.html

it says that " Alerts the operator of positioning errors on each axis. "

Its not closed loop as it will not correct the position on the fly, only report errors. All servo drives that you can use with Mach will fault out if a following error limit is exceeded so no real need for that with a servos system.
Hood

thank you, again and again !! now everything is clear..