Xinje XD Series User Manual

300
7 PID Control Function
In this chapter, we mainly introduce the applications of PID instructions for XD, XL series,
including: call the instructions, set the parameters, items to notice, sample programs etc.
7-1 PID Introduction
PID instruction and auto tune function are added into XD/XL series PLC basic units. Via auto
tune method, users can get the best sampling time and PID parameters and improve the
control precision.
PID instruction has brought many facilities to the users.
Output can be data form D, HD, and on-off quantity Y, user can choose them freely when
programming.
Via auto tune, users can get the best sampling time and PID parameters and improve the
control precision.
User can choose positive or negative action via software setting. Positive action is used for
heating control; negative action is used for cooling control.
PID control separates the basic units with the expansions, which improves the flexibility of
this function.
XD/XL series PLC have two methods for auto tune, step response method and critical
oscillation method.
For temperature control object:
Step response method: the PID auto tune will start when current temperature of object
controlled is equal to ambient temperature.
Critical oscillation method: the PID auto tune can start at any temperature.
7-2 Instruction Form
1)Summary
Execute PID control instructions with the data in specified registers.
PID control [PID]
16 bits
instruction
PID
32 bits
instruction
-
Executing
condition
Normally ON/normally closed
coil trigger
Suitable
models
XD/XL
Hardware
requirement
-
Software
requirement
V3.2 or later
2)Operands
Operands
Function
Type
S1
set the address of the target value (SV)
16bits, BIN
S2
set the address of the tested value (PV)
16 bits, BIN
S3
set the start address of the control parameters
16 bits, BIN
D
the address of the operation result (MV) or output
port
16 its, BIN; bit
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Xinje XD Series Specifications

General

Input Voltage	24V DC
Storage Temperature	-20°C to 70°C
Protection Class	IP20
Type	PLC
Series	XD
Programming Language	Ladder Logic, Instruction List
Communication Interface	RS232, RS485
Power Supply	24V DC
Digital Inputs	Available (number varies by model)
Digital Outputs	Available (number varies by model)
Analog Inputs	Available (number varies by model)
Analog Outputs	Available (number varies by model)
Output Type	Relay, Transistor
Number of Inputs	Varies by model (see Digital Inputs and Analog Inputs)
Number of Outputs	Varies by model (see Digital Outputs and Analog Outputs)
Operating Temperature	0°C to 50°C
Humidity	5% to 95% (non-condensing)