1. Product Introduction

1.1 Product Overview

S-SCPH is one of the intelligent online chemical analyzers developed by our company. It has strong environmental adaptability, clear display, simple operation, and excellent testing performance, making it highly cost-effective. It can accurately measure the pH value and temperature of solutions. It can be widely used for continuous monitoring of pH values in solutions such as thermal power, chemical fertilizers, metallurgy, environmental protection, pharmaceuticals, biochemistry, food, and tap water. Paired with ORP redox electrodes, it is also a precise ORP instrument.

1.2 Functional Features

High intelligence: The online pH meter adopts high-precision AD conversion and single-chip microcomputer processing technology, which can complete various functions such as pH measurement, temperature measurement, and automatic temperature compensation.
Time display: The Chinese online pH meter has a built-in clock chip that can display the current time.
Data storage: The built-in storage chip of the instrument can store historical data from the past three days, making it convenient for users to search.
N Rinse relay: The instrument is equipped with a rinse relay, which can be installed with an electromagnetic valve to regularly clean the pH electrode.
Conversion to 25 ℃: A 25 ℃ reference temperature conversion was performed for pure water and ammonia added ultrapure water, achieving the display of pH at 25 ℃
The n-value is particularly suitable for measuring various water qualities in power plants.
Strong anti-interference ability: using the latest devices with impedance up to 10-12 Ω; The current output adopts photoelectric coupling isolation technology, which has strong anti-interference ability and achieves remote transmission. Has good electromagnetic compatibility.
Simultaneous display of multiple parameters: Display time, pH or mV value, temperature, and output current value simultaneously on the LCD screen. Adopting a high brightness 128 * 64 LCD display module, it is eye-catching and has a long visible distance.
RS485 communication interface: MODBUS RTU communication protocol can be easily connected to a computer for monitoring and communication.
Industrial control watchdog: Ensure that the instrument does not crash.

1.3 Technical indicators

Technical Specifications	technical indicators
execution standard	JB/T 6203-92 "Industrial pH Meter"
PH measurement range	0-14.00pH maximum -2-16PH); Division value: 0.01pH
PH measurement accuracy	±0.02pH
ORP measurement range	-1999~+1999mV; division value: 1mV
ORP measurement accuracy	±1mV
Temperature measurement range	0-99.9 ℃ (maximum -10~120 ℃); Division value: 0.1 ℃
Temperature measurement accuracy	±0.5℃
Automatic temperature compensation range	0-99.9 ℃, based on 25 ℃
Repetitive error of electronic unit	±0.02pH
stability	±0.02pH/24h
input impedance	≥1012Ω
Current isolation output	4～20mA

5. 485 communication protocol
Note: This feature is optional and only available on devices with 485 functionality.

5.1 Basic Communication Parameters

code	8-bit binary
data bit	8 digits
parity bit	none
stop bit	1 person
Error checking	CRC (Redundant Cyclic Code)
Baud rate	Can be set, factory default is 4800bit/s

5.2 Definition of Data Frame Format
Adopting Modbus RTU communication protocol, the format is as follows:
The time for the initial structure to be ≥ 4 bytes
Address code=1 byte
Function code=1 byte
Data area=N bytes
Error check=16 bit CRC code
Time to end structure ≥ 4 bytes
Address code: It is the address of the transmitter and is unique in the communication network (factory default 0x01).
Function code: The instruction function indication issued by the host.
Data area: The data area contains specific communication data, please note that the high byte of 16 bits data comes first!
CRC code: a two byte checksum.
Host query frame structure:

address code	function code	Register starting address	register length	Low byte checksum	High byte checksum
1 byte	1 byte	2 bytes	2 bytes	1 byte	1 byte

Slave response frame structure:

address code	function code	effective byte count	Data Zone 1	Data Zone 2	Data Zone N	Low byte checksum	High byte checksum
1 byte	1 byte	1 byte	2 bytes	2 bytes	2 bytes	1 byte	1 byte

8.3 register address

register address	PLC or configuration address	content	operation	Definition Description
0000 H	40001 (decimal)	PH value	read-only	PH real-time value (expanded by 100 times)
0001 H	40002 (decimal)	temperature value	read-only	Actual temperature value (increased by 10 times)

8.4 Example and Explanation of Communication Protocol

address code function code starting address data length Low byte checksum High byte checksum 0x01 0x03 0x00 0x00 0x00 0x02 0xC4 0x0B

Example: Read device address0x01ofPHValue and temperature value
Inquiry frame




Response frame

address code	function code	Return the number of valid bytes	PH value	temperature value	Low byte checksum	High byte checksum
0x01	0x03	0x02	0x02 0xBC	0x00 0xFA	0xBA	0x2C

Calculation of pH and temperature values:
PH value: 02BC (hexadecimal)=700 (decimal)=>PH value=7.00
Temperature value: 00FA (hexadecimal)=250 (decimal)=>Temperature value=25.0 ℃
9.Precautions and Maintenance
Secondary watches generally do not require daily maintenance. In case of obvious malfunctions, please do not open them for self repair and contact us as soon as possible!
After starting the power supply, the instrument should display. If there is no display or the display is abnormal, the power should be turned off immediately, and the power supply and fuse should be checked for normal operation.
The cable connector must be kept clean and free from moisture or water, otherwise the measurement will be inaccurate.
The electrodes should be cleaned regularly to ensure they are not contaminated.
Calibrate the electrodes periodically.
During the water outage, it is important to ensure that the electrodes are immersed in the tested liquid, otherwise their lifespan will be shortened. The quality of pH meter usage largely depends on the maintenance of the electrode