WIKA Mobile Control LP  
1540 Orchard Drive 
Chambersburg, PA 17201 
 
qSCALE maestro (PLC v01.00.00) Service Manual / Issue E (HMI v1.0.0) 04/2018 / rbm.
 
Service : (717) 217-2250 
Parts / Sales : (717) 217-2269 
www.wika-mc.com 
 
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HIRSCHMANN MCS 
 
 
 
 
 
 
Cable Reel 
6.8  Anti-Two Block Switch (A2B) 
 The system measures the load block and its relationship to the head of the boom.   The A2B switch is 
located at the tip of the boom. 
 
 
   
 
 
 
The signal runs from the A2B as a CAN Bus input of the central unit. 
 
 
 
 
 
NOTE 
Some systems have two (2) A2B switches wired in series. 
 
 
Block Diagram 
A2B 
Sensor 
 
LGH 
Board 
 
CAN Bus  
 
qSCALE