Omron NX-EC0112, User Manual

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8 Pulse Output Units
NX-series Position Interface Units User’s Manual (W524)
8-
10 Fu
nct
ions
8
8-1
0-5 Latching
You can use an external input to latch the present position.
The data that is obtained with the Pulse Output Unit’s latch function is the command current position,
which is represented by the internal output pulse count value.
You can select either a ring or linear counter to obtain the present position with the latch.
Precautions for Correct Use
If you use the error counter reset output, you cannot use latch 1 for a standard latch function.
Latch 1 is used for the homing operation. To use both the following error count reset output and
a standard latch, use latch 2.
You can select either external input 0 (I0) or external input 1 (I1) as the external input latch trigger.
You can use external input 0 (I0) as Latch Input 1 and external input 1 (I1) as Latch Input 2.
Refer to Latch Function on page 8-38 for information on latching for an external input.
Refer to External Input Function Selection on page 8-65 for information on the external inputs (I0 and
I1).
When you select an N.O. contact for the external input logic, the present value is latched on the rising
edge of the selected external input (I0 or I1). When you select N.C. contact for the external input logic,
the present value is latched on the falling edge of the external input. The latch value is updated every
time the present value is latched.
You can assign up to two external inputs as latch inputs, each with an I/O data input area allocation.
 Trigger Conditions
There are the following two input trigger conditions for latching.
8-10-5 Latching
Latching with an External Input
Input trigger condition Description
One-shot Mode After you change Latch Input 1 Enable or Latch Input 2 Enable bit from 0 to 1, the
present position of the encoder is latched for the first detected latch input. No more
latching is performed for this latch input until you change the Latch Input 1 Enable
or Latch Input 2 Enable bit to 0 and then back to 1 again.
Continuous Mode While the Latch Input 1 Enable or Latch Input 2 Enable bit is 1, the present position
of the encoder is latched and the latch value is updated every time a latch input is
detected.
Latch data is updated
to the present value. Latch data is updated to
the present value.
N.O. contact N.C. contact