Delta Tau PMAC2A-PC/104 ユーザーズマニュアル

Each channel of PMAC has five dedicated digital inputs on the machine connector: PLIMn, MLIMn 
(overtravel limits), HOMEn (home flag), FAULTn (amplifier fault), and USERn.  A power supply from 5 
to 24V must be used to power the circuits related to these inputs.  This power supply can be the same 
used to power PMAC and can be connected from the TB1 terminal block or the JMACH1 connector.  

When assigned for the dedicated uses, these signals provide important safety and accuracy functions.  
PLIMn and MLIMn are direction-sensitive over-travel limits that must conduct current to permit motion 
in that direction.  If no over-travel switches will be connected to a particular motor, this feature must be 
disabled in the software setup through the PMAC Ix25 variable. 

PMAC expects a closed-to-ground connection for the limits to not be considered on fault.  This 
arrangement provides a failsafe condition.  Usually, a passive normally close switch is used.  If a 
proximity switch is needed instead, use a 5 to 24V normally closed to ground NPN sinking type sensor. 

 

While normally closed-to-ground switches are required for the overtravel limits inputs, the home switches 
could be either normally close or normally open types.  The polarity is determined by the home sequence 
setup, through the I-variables I9n2.  However, for the following reasons, the same type of switches used 
for over-travel limits are recommended: 

• 

Normally closed switches are proven to have greater electrical noise rejection than normally open types. 

• 

Using the same type of switches for every input flag simplifies maintenance stock and replacements. 

Each JMACH1 connector provides two +5V outputs and two logic grounds for powering encoders and 
other devices.  The +5V outputs are on pins 1 and 2; the grounds are on pins 3 and 4.  The encoder signal 
pins are grouped by number: all those numbered 1 (CHA1+, CHA1-, CHB1+, CHC1+, etc.) belong to 
encoder #1.  The encoder number does not have to match the motor number, but usually does.  Connect 
the A and B (quadrature) encoder channels to the appropriate terminal block pins.  For encoder 1, the 
CHA1+ is pin 5 and CHB1+ is pin 9.  If there is a single-ended signal, leave the complementary signal 
pins floating – do not ground them.  However, if single-ended encoders are used, check the settings of the 
resistor packs (see the Hardware Setup section for details).  For a differential encoder, connect the 
complementary signal lines – CHA1- is pin 7, and CHB1- is pin 11.  The third channel (index pulse) is 
optional; for encoder 1, CHC1+ is pin 13, and CHC1- is pin 15. 

Example: differential quadrature encoder connected to channel #1: