Mitsubishi Electric FR-A720-00030-NA Instruction Manual page 399

Special operation and frequency control
(4) Synchronous speed operation by pulse I/O
Inverter (master)
JOG
Pulse train
output
* When the wiring length between FM and JOG is long, a pulse shape is deformed due to the stray capacitances of the wiring and input pulse can not be
recognized.
When wiring length is long (10m (32.8feet) or more of 0.75mm
up resistance. The reference of resistance value to the wiring length is as in the table below.
Stray capacitances of the wiring greatly differ according to the cable type and cable laying, the above cable length is not a guaranteed value.
When using a pull up resistance, check the permissible power and permissible load current (terminal PC : 100mA, high speed pulse train output : 85mA) of the
resistor and use them within a permissible range.
· By setting "100" in Pr. 291, pulse train input can be output at pulse train output (terminal FM) as it is.
Synchronous speed operation of multiple inverters can be enabled by daisy chain connection.
· Since maximum pulse train output is maximum of 50k pulse/s, set "125" in Pr. 384 of the inverter receiving pulse train.
· When operating two or more inverters synchronously, perform wiring according to the following steps. (so that 24V
contact input will not be applied to terminal FM)
1) Set pulse train output (a value other than "0, 1") in Pr. 291 of the master side inverter.
2) Turn OFF the inverter power
3) Perform wiring of the master side terminal FM-SD and slave side terminal JOG-SD
4) Turn ON the inverter power
CAUTION
· After changing a setting value of Pr. 291, connect JOG terminal between terminal FM and SD. Take note that a voltage should
not be applied to terminal FM specially when FM output (voltage output) pulse train is selected.
· For the slave side inverter, use sink logic (factory setting). The inverter will not function properly if source logic is selected.
Specifications of synchronous speed operation
Item
Output pulse type
Pulse rate
Pulse transmission delay
* When a pulse transmission delay in a slave is approximately 1 to 2s and wiring length is long, the delay further increases.
Parameters referred to 
Pr. 291 (pulse train output )
388
To next inverter (slave)
Pull up
resistance*
PC
Speed
command
FM JOG
SD SD
2
twisted cable is recommended), connect terminal JOG and terminal PC using an external pull
Specifications
Pulse width is fixed (10s)
0 to 50kpps
1 to 2s per inverter *
Refer to page 263
Speed
Pulse train
command
input
FM
Pulse train
SD
output
To next inverter (slave)