Hitachi SJ700-2 Analog command holding function AHD, Intelligent pulse counter Pcnt and PCC

Related code

C001 to C008: Terminal [1] to terminal [8] functions

d028: Pulse counter monitor

Related code

C001 to C008: Terminal [1] to [8] functions

C101 : UP/DWN holding function

Chapter 4 Explanation of Functions

The speed control normally incorporates the proportional integrated compensation (PI control), and the motor speed is controlled so that the difference between the frequency specified by the frequency command and the actual motor speed is zero. However, a specific operation mode (called drooping operation), in which one load is driven by multiple motors, sometimes requires the proportional control (P control). To enable the proportional (P) control mode, assign function "43" (P/PI switching function) to one of the terminal

[1]to [8] functions (C001 to C008), and turn on the intelligent input terminal. For the proportional control, set the value of the P control proportional gain (H052) as the KPP value.

The following formula generally represents the relation between the KPP value and momentary speed variation:

(Momentary speed variation) =	10	(%)
	(Set value of KPP)

P control mode

Torque

100%

0

PI control mode

(A)

Rotation speed

The following formula generally represents the relation between the momentary speed variation and speed error:

(Momentary speed variation) =	Speed error at rated torque (A)	⋅ 100%
	Synchronous rotation speed at base frequency

4.2.56 Analog command holding function (AHD)

- The analog command holding function allows you to make the inverter hold the analog command input via the external analog input terminal when the AHD terminal is on.

-While the AHD terminal is on, the up/down function can be used based on the analog signal held by this function as reference data.

-When "01" is specified for Up/Down memory mode selection (C101), the result of up/down processing can be stored in memory.

-If the inverter power is turned on or the RS terminal turned off with the AHD terminal left turned on, the data held immediately before power-on or turning off the RS terminal will be used.

Item	Function code	Data	Description
Terminal [1] to [8] functions	C001 to C008	65	AHD: Analog command holding

AHD terminal

Input analog command

Frequency command

ON

Remark)

Set frequency remains when inverter is switched with SET/SET3 terminal with AHD on. Turn AHD terminal off to re-hold the set frequency.

4.2.57 Intelligent pulse counter (PCNT and PCC)

- The intelligent pulse counter function allows you to input a pulse train via an intelligent input terminal.

-The cumulative count of input pulses can be monitored by the pulse counter monitor (d028) function.

-The value of cumulative counter cannot be stored. The counter value is cleared to zero when the inverter power is turned on or the inverter reset.

-Turning on the PCC (pulse counter clear)terminal clears the cumulative counter.

-The frequency resolution of the input pulse can be calculated by the formula shown below (for pulse signal input with a duty ratio of 50%). Frequencies not less than the relevant resolution cannot be input. It is recommended to use this function up to 100Hz. For the input terminal response, see Section 4.2.79.

Frequency resolution (Hz) = 250/(input terminal response time setting [C160 to C168] + 1) Example: When the input terminal response time is 1, the frequency resolution is 125 Hz.

			Input terminal response
Input pulse
	ON
PCNT	OFF
Value of counter		1	2	4 - 59	3	4