The QX Series has two backpack options, HE-BP41 & HE-BP43 - with high speed counter.
Both are compact and easy-to-install on the back of the QX base unit.
With any backpack installed, up to two SmartStack I/O modules can be snapped on.
Additionally, backpack users can connect hundreds of local or remote I/O using our Fiber Optic (FOX) Expansion I/O and our SmartStix terminal-type I/O modules.