Mitsubishi Electric FR-A760 Series Instruction Manual page 375

Special operation and frequency control
* When the wiring length of the open collector output connection is long, input pulse can not be recognized because of a pulse shape deformation due to the
stray capacitances of the wiring.
When wiring length is long (10m (32.8feet) or more of 0.75mm
using a pull up resistance. The reference of resistance value to the wiring length is as in the table below,
Wiring Length
Pull up/down resistance
Load current (for reference)
Stray capacitances of the wiring greately differ according to the cable type and cable laying, the above cable length is not a guaranteed value.
When using a pull up/down resistance, check the permissible power of the resistor and permissible load current of output transistor and use them within a
permissible range.
REMARKS
· When pulse train input is selected, a function assigned to terminal JOG using Pr. 185 JOG terminal function selection is made invalid.
· When Pr. 419 Position command source selection = "2" (conditional position pulse train command by inverter pulse train input),
JOG terminal serves as conditional position pulse train terminal regardless of the Pr. 291.
CAUTION
· Since Pr. 291 is a selection parameter for pulse train output/FM output, check the specifications of a device connected to
terminal FM when changing the setting value. (Refer to page 244 for pulse train output.)
· Output specifications (high speed pulse train output or FM output) of terminal FM can be selected using Pr. 291. Change the
setting value using care not to change output specifications of terminal FM. (Refer to page 244 for pulse train output.)
Pulse train input specifications
Item
Available pulse method
H input level
L input level
Maximum input pulse rate
Minimum input pulse width
Input resistance/load current
Maximum wiring
Open collector output system
length
Complemenraty output system 100m (328.09feet) (output resistance 50
(reference value)
Detection resolution
60Hz
Pr. 386
(Hz)
0Hz
0
Maximum input pulse
Pr. 385
(3) Calculation method of division scaling factor of input pulse (Pr. 384 )
· Maximum input pulse can be calcualted from the following formula using Pr. 384 Input pulse division scaling factor.
Maximum of input pulse (pulse/s) = Pr. 384 × 400
(maximum of 100kpulse/s)
(Detectable pulse = 11.45 pulse/s)
· For example, when you want to operate at 0Hz when pulse train input is zero and operate at 30Hz when pulse train
is 4000 pulse/s, set parameters as below.
Pr. 384 = 10
(maximum input pulse 4000 pulse/s)
Pr. 385 = 0Hz, Pr. 386 = 30Hz
(pulse train limit value is 33Hz)
REMARKS
The priorities of the frequency commands by the external signals are "jog operation > multi-speed operation > teminal 4 analog
input > pulse train input".
When pulse train input is made valid (when Pr. 291 = "1, 11, 21, or 100" and Pr. 384
364
2
twisted cable is recommended), connect an open collector output signal and power supply
Less than 10m 10 to 50m
(Less than 32.8feet) (32.8 to 164.04feet)
Not necessary
10mA 35mA
20V or more (voltage between JOG-SD)
5V or less (voltage between JOG-SD)
10m (32.8feet) (0.75mm
Limit value
*
Input pulse
(pulse/s)
50 to 100m
(164.04 to 328.09feet)
1kΩ 470Ω
65mA
Specifications
Open collector output
Complementary output
(power supply voltage 24V)
100kpps
2.5us
2k (typ) / 10mA (typ)
Ω
2
/ twisted pair)
1/3750
(2) Adjustment of pulse train input and frequency
(Pr. 385, Pr. 386 )
· Frequency for zero input pulse can be set using Pr. 385
Frequency for zero input pulse and frequency at maximum input
pulse can be set using Pr. 386 Frequency for maximum input
pulse.
* Limit value can be calculated from the following formula.
(Pr. 386 - Pr. 385 ) × 1.1 + Pr. 385
≠
"0"), terminal 2 analog input is made invalid.
* The wiring length of complementary
output depends on the output wiring
specifications of complementary
output device.
Stray capacitances of the wiring
greatly differ according to the cable
type and cable laying, the
)
Ω
*
maximum cable length is not a
guaranteed value.