Kofloc EX-250S User manual

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Thermal Digital Mass Flow Meter / Controller
EX-250S
RS-485 Communications
Instruction Manual

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Table of Contents
Page
1．Foreword・・・・・・・・・・・・・・・・・・・・・・・・・・・ 2
2．Switching to “control by digital communications”・・・・・・・・・・・2
3．Basic Specifications・・・・・・・・・・・・・・・・・・・・・・・ 4
4．Message Structure・・・・・・・・・・・・・・・・・・・・・・・ 5
5．Details of Commands・・・・・・・・・・・・・・・・・・・・・・ 7
1) RCFS：Acquisition of the full scale flow rate [significand]・・・・・・・ 7
2) RDPP：Acquisition of the flow rate decimal point position
[number of decimal places]・・・・・・・・・ 7
3) RFRU：Acquisition of the flow rate unit・・・・・・・・・・・・・・・ 7
4) RFRC：Acquisition of the flow rate reference temperature condition・・ 8
5) WFRC：Setting of the flow rate reference temperature condition・・・・ 8
6) RCFR：Acquisition of the instantaneous flow rate [significand]・・・・・ 8
7) RPGT：Acquisition of the calibration gas type・・・・・・・・・・・・ 8
8) RCGT：Acquisition of the gas type・・・・・・・・・・・・・・・・・ 9
9) RCFM：Acquisition of the CF value in the user custom CF mode・・・・ 9
10) WCFM：Setting of the CF value in the user custom CF mode・・・・・ 9
11) RLFD ：Acquisition of the display cut setting (0 shown if within ±1%F.S.)・ 10
12) WLFD：Setting of the display cut setting (0 shown if within ±1%F.S.) ・・ 10
13) RALM：Acquisition of the alarm occurrence status・・・・・・・・・・ 10
14) ZERO：Execution of sensor zero adjustment・・・・・・・・・・・・ 10
- - - - - -The following are commands used by the mass flow controller only - - - - - - -
15) RCVS：Acquisition of the valve status・・・・・・・・・・・・・・・ 11
16) RCVO：Acquisition of the valve opening・・・・・・・・・・・・・・ 11
17) RSFR：Acquisition of the set flow rate [significand]・・・・・・・・・・ 11
18) RRDP：Acquisition of the motion differential pressure・・・・・・・・ 11
19) WRDP：Setting of the motion differential pressure ・・・・ ・・・・・・ 12
20) RFSM：Acquisition of the flow rate setting method・・・・・・・・・・ 12
21) WFSM：Setting of the flow rate setting method・・・・・・・・・・・・ 12
22) RVSS：Acquisition of the valve status (digital)・・・・・・・・・・・・ 12
23) WVSS：Setting of the valve status (digital)・・・・・・・・・・・・・・ 12
24) RSFD：Acquisition of the set flow rate [significand] (digital) ・・・・・・ 13
25) WSFD：Setting of the set flow rate [significand] (digital)・・・・・・・・ 13
26) RALA：Acquisition of the response to alarm occurrence・・・・・・・・ 13
27) WALA：Setting of the response to alarm occurrence ・・・・・・・・・ 13
28) RAZS：Acquisition of the auto zero ・・・・・・・・・・・・・・・・ 14
29) WAZS：Setting of the auto zero・・・・・・・・・・・・・・・・・・ 14
6．Flow Rate Expression・・・・・・・・・・・・・・・・・・・・・・15

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1. Foreword
This document describes the specifications and handling of the RS-485 communications
function installed as a standard feature in EX-250S.
The wiring, installation and operating procedures, other than communications, are
presented in a separate instruction manual. Prior to use, please read it also.
2. Switching to “control by digital communications”
(Mass flow controller only)
EX-250S has been set to “control by analog input” in the factory.
When you require “control by digital communications”, first change the flow rate
setting method to “digital (0)” in accordance with the procedure described below. To
return to “control by analog input”, change it to “analog (1)” again.
※Reference 5. Command Details 21) WFSM: Setting of the flow rate setting method
When the valve open/close input (analog signal) is “CLOSE” (fully close) or “OPEN”
(fully open), the equipment follows it regardless of the setting of the flow rate setting
method. Only when “CONTROL”, the action is switched over according to the
setting of the flow rate setting method as shown on the next page, but a difference
in action due to a difference in setting is limited to this part and others remain the
same. The flow rate control range is 2% to 100% of the full scale. The setting less
than 2% is “CLOSE”.

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Valve open/close input (analog signal)
Fully close ( -15V ) Control ( OPEN ) Fully open ( +15V )
The valve status (digital)
Fully close (2)
Fully close
Controlled by
flow rate setting
voltage/current inputs
(analog signals)
Fully open
Control (1)Fully open (0)
Flow rate setting method “Analog (1)”
Valve open/close input (analog signal)
Fully close ( -15V ) Control ( OPEN ) Fully open ( +15V )
The valve status (digital)
Fully close (2)
Fully close
Fully close
Fully open
Control (1)
Controlled by
the set flow rate
[significand]
(digital setting)
Fully open (0)
Fully open
Flow rate setting method “Digital (0)”

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3. Basic Specifications
Synchronization Start-stop
Transmission speed 38400 bps
Start bit 1 bit
Data length 8 bits
Stop bit 1 bit
Parity None
Transmission system 3-wire half-duplex
Insulation Communication – control circuit: Uninsulated
Communication – power supply: Uninsulated
Communication ID setting By use of rotary switch SW2 on top of equipment
Using the switch SW2 on the top of the equipment, set a communication ID (1 – 9) for each
piece of the equipment. When setting an ID, ensure that IDs do not overlap among the
equipment and are unique ones.
With the user system such as a PC and PLC as the master and this equipment as the slave,
sending a command message from the master begins communications and returning a
response message from the slave ends communications. Since the master and each slave
share the message send/receive path, follow this procedure to ensure that messages do not
collide.

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4. Message Structure
・Command message
The command message from the communication controller to the equipment
should be structured as shown in the following example:
STX Communication ID Command Data Check sum ETX
@ 0 0 1 W V S S 1 5 5 CR
40H 30H 30H 31H 57H 56H 53H 53H 31H 35H 35H 0DH
STX
This equipment recognizes “STX” as the head of the message unconditionally.
“@(40H)” Fixed length 1 byte
Communication ID Specify a communication ID of the equipment to which data is sent.
“001” – “099” Fixed length 3 bytes
Command Specify a character string to indicate a command type. Fixed length
4 bytes. For details, see the next section.
Data Variable length according to command types. There are commands
without data. For details, see the next section.
Check sum Added every 1 byte from STX to data and each digit of calculation
result lower 2 digits (hexadecimal) converted to ASCHII code. Fixed
length 2 bytes. ※See below.
ETX Indicates the end of the message. “CR (0DH)” Fixed length 1 byte
※An example of check sum calculation
As an example, the above command message is as follows:
40H + 30H + 30H + 31H + 57H + 56H + 53H + 53H + 31H = 255H
(STX) (Communication ID) (Command) (Data)(Check sum)

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・Response message
When the communication ID that has been set to the equipment matches the
communication ID specified by the command message, the equipment returns a
response message as shown in the following example.
STX Communication ID Command Exit code Data Check sum ETX
% 0 0 1 R V S S O K 1 C F CR
25H 30H 30H 31H 52H 56H 53H 53H 4FH 4BH 31H 43H 46H 0DH
STX “％(25H)” Fixed length 1 byte
Communication ID Communication ID of source equipment. Fixed length 3 bytes
Command A character string to indicate a command type contained in the
command message. For details, see the next section. Fixed length
4 bytes.
Exit code A character string to indicate a result of the command message.
“OK” or “NG” Fixed length 2 bytes
Data Variable length according to command types and exit code. There
are commands without data (0 byte). For details, see the next
section.
Check sum Added every 1 byte from STX to data and each digit of calculation
result lower 2 digits (hexadecimal) converted to ASCHII code. Fixed
length 2 bytes.
ETX Indicates the end of the message. “CR (0DH)” Fixed length 1 byte
※The check sum is calculated by the same method as the command message.

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5. Details of Commands
The commands that can be executed for the equipment will be described below.
Please note that KOFLOC will bear no responsibility for motions resulting from the
use of commands other than those specified here.
1) RCFS：Acquisition of the full scale flow rate [significand]
The full scale flow rate [significand] is acquired.
This is used to calculate the full scale flow rate currently set to the equipment
together with the flow rate decimal point position [number of decimal places] and
flow rate unit.
Data Command: None
Response: Decimal 4 digits (fixed length 4 bytes)
Range: 0001 －9999
2) RDPP：Acquisition of the flow rate decimal point position [number of
decimal places]
The flow rate decimal point position [number of decimal places] is acquired.
This is used to calculate various flow rates together with the flow rate unit.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：None, 1：1 digit, 2：2 digits, 3：3 digits
3) RFRU：Acquisition of the flow rate unit
The flow rate unit is acquired.
This is used to calculate various flow rates together with the flow rate decimal
point position [number of decimal places].
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：cc , 1：L

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4) RFRC：Acquisition of the flow rate reference temperature condition
The flow rate reference temperature condition is acquired.
Data Command: None
Response: Decimal 2 digits (fixed length 2 bytes)
00：0℃, 20：20℃, 25：25℃
5) WFRC：Setting of the flow rate reference temperature condition
Set the flow rate reference temperature condition.
Data Command: Decimal 2 digits (fixed length 2 bytes)
00：0℃, 20：20℃, 25：25℃
Response: None
6) RCFR：Acquisition of the instantaneous flow rate [significand]
The instantaneous flow rate [significand] is acquired.
This is used to calculate the instantaneous flow rate together with the flow rate
decimal point position [number of decimal places] and flow rate unit.
Data Command: None
Response: Sign (‘+’ / ‘-’) Decimal 4 digits (fixed length 5 bytes)
Range: -9999 －+9999
7) RPGT：Acquisition of the calibration gas type
The calibration gas type used for equipment calibration is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
1：N
2
(Nitrogen)
2：AIR (Air)
3：H
2
(Hydrogen)
4：He (Helium)
5：Ar (Argon)
6：O
2
(Oxygen)
7：CO
2
(Carbon dioxide)
0：Other than above

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8) RCGT：Acquisition of the gas type
The present gas type that has been set is acquired.
Selected by the switch SW1 on the top of the equipment.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
1：N
2
(Nitrogen)
2：AIR (Air)
3：H
2
(Hydrogen)
4：He (Helium)
5：Ar (Argon)
6：O
2
(Oxygen)
7：CO
2
(Carbon dioxide)
8：Other gas specified when an order is placed
9：User custom CF mode
0：Other than above
9) RCFM：Acquisition of the CF value in the user custom CF mode
The CF value in the user custom CF mode is acquired.
This is expressed always based on N2 (nitrogen) (1000) regardless of
calibration gas types.
Data Command: None
Response: Decimal 4 digits (fixed length 4 bytes)
Range: 0200 －1500
10) WCFM：Setting of the CF value in the user custom CF mode
Set the CF value in the user custom CF mode. Set this always based on N
2
(nitrogen) (1000) regardless of the calibration gas types.
Data Command: Decimal 4 digits (fixed length 4 bytes)
Range: 0200 －1500
Response: None

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11) RLFD：Acquisition of the display cut setting (0 shown if within ±1%F.S.)
The display cut setting (0 shown if within ±1%F.S.) is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Disable (No display cut)
1：Enabled (Forced indication of “0”)
12) WLFD：Setting of the display cut setting (0 shown if within ±1%F.S.)
Set the display cut setting (0 shown if within ±1%F.S.)
Data Command: Decimal 1 digit (fixed length 1 byte)
0：Disable (No display cut)
1：Enabled (Forced indication of “0”)
Response: None
13) RALM：Acquisition of the alarm occurrence status
The alarm occurrence status is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：No alarm
1：Alarm present (Sensor error)
2：Alarm present (Valve overheat)
3：Alarm present (Sensor faulty and valve overheated)
14) ZERO：Execution of sensor zero adjustment
Sensor zero adjustment is executed.
Ensure that no gas is flowing before starting adjustment.
Data Command: None
Response: None

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The following are commands used by the mass flow controller only.
15) RCVS：Acquisition of the valve status
The present valve status is acquired regardless of analog input or digital setting.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Fully open, 1：Control, 2：Fully close
16) RCVO：Acquisition of the valve opening
The present valve opening is acquired.
Data Command: None
Response: Decimal 4 digits (fixed length 4 bytes)
Range: 0000 －1000 (in units of 0.1%)
17) RSFR：Acquisition of the set flow rate [significand]
The set flow rate [significand] is acquired.
This is used to calculate the set flow rate together with the flow rate decimal
point position [number of decimal places] and flow rate unit.
The currently set flow rate is acquired regardless of the setting of the flow rate
setting method.
Data Command: Decimal 4 digits (fixed length 4 bytes)
Range: 0000 －9999
Response: None
18) RRDP：Acquisition of the motion differential pressure
The motion differential pressure is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Standard differential pressure, 1：Low differential pressure

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19) WRDP：Setting of the motion differential pressure
Set the motion differential pressure.
Data Command: Decimal 1 digit (fixed length 1 byte)
0：Standard differential pressure, 1：Low differential pressure
Response: None
20) RFSM：Acquisition of the flow rate setting method
The flow rate setting method is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Digital, 1：Analog
21) WFSM：Setting of the flow rate setting method
Set the flow rate setting method.
Data Command: Decimal 1 digit (fixed length 1 byte)
0：Digital, 1：Analog
Response: None
22) RVSS：Acquisition of the valve status (digital)
The valve status (digital) is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Fully open, 1：Control, 2：Fully close
23) WVSS：Setting of the valve status (digital)
Set the valve status (digital).
Data Command: Decimal 1 digit (fixed length 1 byte)
0：Fully open, 1：Control, 2：Fully close
Response: None

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24) RSFD：Acquisition of the set flow rate [significand] (digital)
The set flow rate [significand] (digital) that has been set is acquired.
This is used to calculate the set flow rate (digital) together with the flow rate
decimal point position [number of decimal places] and flow rate unit.
Data Command: None
Response: Decimal 4 digits (fixed length 4 bytes)
Range: 0000 －9999
25) WSFD：Setting of the set flow rate [significand] (digital)
Set the set flow rate [significand] (digital).
Set the set flow rate (digital) together with the flow rate decimal point position
[number of decimal places] and flow rate unit.
Data Command: Decimal 4 digits (fixed length 4 bytes)
Range: 0000 － full scale flow rate [significand]
However, setting less than 2% of the full scale flow rate
[significand] is treated as fully closed.
Response: None
26) RALA：Acquisition of the response to alarm occurrence
The response to alarm occurrence is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Valve control continued,
1：Valve forced to fully closed
2：Valve forced to fully opened
27) WALA：Setting of the response to alarm occurrence
Set the response to alarm occurrence.
Data Command: Decimal 1 digit (fixed length 1 byte)
0：Valve control continued
1：Valve forced to fully closed
2：Valve forced to fully opened
Response: None

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28) RAZS：Acquisition of the sensor auto zero
The sensor auto zero is acquired.
Data Command: None
Response: Decimal 1 digit (fixed length 1 byte)
0：Disabled
1：Enabled
29) WAZS：Setting of the senor auto zero
Set the sensor auto zero.
Data Command: Decimal 1 digit (fixed length 1 byte)
0：Disabled
1：Enabled
Response: None

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6. Flow Rate Expression
The maximum full scale flow rate, full scale flow rate, instantaneous flow rate, set
flow rate (digital) and set flow rate are expressed by a combination of the significand
and flow rate decimal point position [number of decimal places] and flow rate unit.
Note that flow rate decimal point position [number of decimal places] and flow rate
unit are used commonly for each flow rate and cannot be changed.
Examples are presented below:
Full scale flow rate [significand] 3000
Flow rate decimal point position [ number of decimal places] 1：1 digit
Flow rate unit 0：cc
Full scale flow rate 300. 0 (cc)
Instantaneous flow rate [significand] 1234
Flow rate decimal point position [ number of decimal places] 2：2 digits
Flow rate unit 0：cc
Instantaneous flow rate 12. 34 (cc)
Set flow rate [significand] (digital) 0500
Flow rate decimal point position [ number of decimal places] 3：3 digits
Flow rate unit 1：L
Set flow rate (digital) 0. 500 (L)
Set flow rate [significand] 2500
Flow rate decimal point position [ number of decimal places] 1：1 digit
Flow rate unit 0：cc
Set flow rate 250. 0 (cc)

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