9 Application Instructions API 150-199 enabled. f) When the instruciton is enabled in an EH2/SV series MPU, the EH2/SV series MPU searches for the DOG signal in the negative direction. g) When the instruciton is enabled in an EH3/SV2 series MPU, and the negative limit function is selected, the PLC searches for the DOG signal in the negative direction. If the PLC meets the negtavie limit during the process, it will search for the DOG signal in the positive direction. When the instruciton is enabled in an EH3/SV2 series MPU, but the negative limit function is not enabled, the PLC automatically refers to the present position of the axis, and searches for the DOG signal in the direction of 0.
For example, if the poresent position of CH0 (D1336, D1137) is greater than or equal to 0, CH0 will search for the DOG signal in DOG singal in the positive direction. the negative direction. If the poresent position of CH0 (D1336, D1137) is less than 0, CH0 will search for the Frequency S 3 near point signal =On Target frequency (S ) 1 ) 2 Start frequency (S ) 2 time Enabling the instruction S 3 near point signal =Off h) ZRN (DZRN) instruction is applicable to servo motor with absolute positioning function, e.g. Mitsubishi MR-J2-A servo drive. Even when the power is switched off, the current position can still be recorded.
In addition, the current position of servo drive can be read by API 155 DABSR of EH2/SV/EH3/SV2/SC series MPU; therefore only one zero return operation is required and no zero return has to be done after the power is switched off. i) When the drive contact of ZRN instruction is On, CH0 (CH1) will read the acceleration/deceleration time set in D1343 (D1353) and accelerate to the zero return speed, waiting for the DOG and decelerate to creep speed. When the DOG is Off, the pulse output will stop immediately. j) For SC series MPU, many ZRN instructions can be compiled in the program but only one instruction can be executed when the PLC program is being executed.
For example, provided there is already an instruction enabling Y10 output, other instructions enabling also Y10 output will not be executed. The principle of the instruction execution is “first come, first executed”. k) For SC series MPU, when you designate Y10 as the output device, you can choose either X10 or X11 for DOG input in the “acceleration to deceleration” segment. In other words, when designating Y11 as the output device, you can also choose either X10 or X11 for DOG input. DVP-PLC Application Manual 9-47 accel/decel. time D1343 acceleration deceleration