No.GCSC3E2  2008. 05 To prevent the accidents by mishandling of this controller, please arrange to give this manual into the hands of the operator who actually uses our products. Warning Turn the power supplied to the instrument OFF before wiring or checking. If working or touching the terminal on the power ON status, there is a possibility of Electric Shock which can cause severe injury or death.
1. System configuration
1.2 When executing setting value digital transmission by option C5. Maximum 31 units of GCS-300 [Fig. 1.2-1] The main setting value of PC-900 [option code: SVTC] can be transmitted in digital to the GCS-300 [option code: C5]. • Fit the transfer rate of PC-900 and GCS-300 when transmitting the main setting value in digital, and designate Lock 3 in Setting value lock designation of the GCS-300. • Maximum 31 units of GCS-300 are connectable to one PC-900. ● Notices when using the setting value digital transmission [Option code: SVTC] • Memory life of the GCS-300 is approximately 1 000 00 (one million) times in writing. Therefore when frequently writing the command, designate Lock 3 in Setting value lock of the GCS-300, since it has no relation to memory life. If the Lock 3 is not designated, it writes the memory every time the setting command is sent, and the memory life becomes shorter. • Fit the transfer rate of GCS-300 and PC-900. • It is not necessary to set instrument number to the GCS-300.
2. Connection
RS-485 [option code: C5] ● When the converter is IF-100-C5, and between the converter and host computer is connected by RS-232C. Connection: RS-232C ↓── RS-485 (Data transfer rate: 1200, 2400, 4800 or 9600bps) When communicating by the transfer rate 19200bps, use IF-300-C5 instead of IF-100-C5 for the converter. ● In case the converter is IF-100-C5, and between the converter and host computer is connected by RS-422A. Connection: RS-422A ★─➤ RS-485 (Data transfer rate: 1200, 2400, 4800 or 9600bps) ●  Setting value digital transmission (Option code: SVTC) When the option C5 (RS-485) is applied, connect the wire between the PC-900 and the GCS-300 as shown below. ● As for the shielding wire • Connect the shielding wire only one side to FG or ground (GND) terminal so as not to flow the current into the shielding wire. If both sides of the wire are connected to the FG or ground terminal, the circuit is made between the wire and ground, and the noise may easily occur by the current. • The FG or ground terminal must be grounded. ● As for the terminator (Terminal resistor) • The more the communication line becomes long, the less the communication performs because the transfer waveform becomes wrong owing to the echo. To prevent this, connect the terminator. • The place to connect should be the physical terminal of the communication cable. ● Communication converter of [IF-100-C5] or [IF-300-C5] is provided on separate sale. 3.As for the instrument setting • When communicating by connecting plural GCS-300s in serial communication [option C5], the instrument number should be set individually. • Select the data transfer rate for the GCS-300 to fit the host computer. • Refer to the instruction manual of GCS-300 for the instrument number setting and data transfer rate selection.
4. Communication procedure
RS-485 [Option code: C5] Communications between a host computer and the GCS-300 are started by sending the command from the host computer, and terminated by receiving the response from the GCS-300. Host computer
GCS-300

• Response with data When the host computer sends the reading command, GCS-300 returns the corresponding setting value or current status as the response. If the host computer sends the setting command, GCS-300 returns acknowledgement (ACK) as the response after the processing is terminated. Negative Acknowledgement When the host computer sends the command not existent or the value beyond setting range, GCS-300 returns negative acknowledgement (NAK) for the response. No response GCS-300 will not respond when framing error or checksum error has been detected while the command is being received. No response ↑…………… ● Communication timing of RS-485 [Option code: C5] • As to the GCS-300 side When the GCS-300 starts transmission to RS-485 communication line, the GCS-300 is arranged so as to provide 1 character transmission period or more of idle status (mark status) to make the synchronous sure on the receiving side. The GCS-300 is arranged so as to cut the transmitter off from the communication line within the period of 1 character transmission after sending the response. Make the program so that the host computer can provide 1 character transmission period or more of idle status (mark status) before sending the command to make the synchronous sure on the receiving side when the host computer starts the transmission to RS-485 communication line. Make the program so that the host computer can cut the transmitter off from the communication line within the period of 1 character transmission after sending the command in preparation for reception of the response from the GCS-300. To avoid the collision of transmission between the host computer and the GCS-300, send the next command after checking that the host computer surely received the response. In case the host computer communicates with the GCS-300 through the line converter (IF-100-C5, IF-300-C5, sold separately), it is not required to manage the transmission timing described above because the converter takes the timing interpreting the protocol automatically. 5.1 Command configuration All commands are composed of ASCII codes. The data (setting value) are converted to Hexadecimal number and  ASCII codes are used for the command. Negative number is represented by 2's complement.
(2) Response to the command • Response with data (Response to the reading command)
Data item   : It represents the data sort for the command. It is made up by 4 digits of hexadecimal number. (Refer to the command table.) The same code as the received command is used for the response.
The contents of the data differ by the reading command. It is made up by 4 digits of hexadecimal number. (Refer to the command table.) : 2-character of data to detect a communication error. : ETX (03H, fixed), End of text. Control code to represent the ending of the response. ●
[Fig. 5.1-3]
: ACK(06H fixed), [Acknowledgement] Control code to represent the beginning of the response. : It represents the instrument number 0 to 95 (20H to 7FH). The same code as the received command is used for the response. : 2-character of data to detect a communication error. : ETX (03H, fixed), End of text. Control code to represent the ending of the response.
[Fig. 5.1-4]
Checksum is used to detect a receiving error of the command or data. Make the program for the host computer side as well to calculate the checksum of the response data from the GCS-300 to check the communication error. ASCII code (hexadecimal) corresponding to the character from the address (instrument number) to the character front of the checksum is converted to binary notation, and the total value is made. The lower 2-digit of the total value are converted to 2’s complements and further to hexadecimal, that is, ASCII code. This is the checksum. Refer to the following example procedure. ● Checksum calculation example is shown as follows. Main setting value: 600℃ (Fixed value control) [Hexadecimal] [Binary notation]
[Code to be transmitted]
Though lock mode is designated by Setting value lock, the setting by setting command is effective. • Even if the option is not applied, it is possible to set by setting command, however, the setting is ineffective. • The life of memory is approximately 1 000 000 (one million) in number of times of writing. If the number of times exceeds the limit, it cannot memorize the data. • When connecting plural GCS-300s, the same instrument numbers should not be applied to the plural GCS-300s. • When sending the command by Global address [95 (7FH)], the same command is sent to all GCS-300s connected. However, the response is not returned. • The instrument number and data transfer rate of GCS-300 cannot be set by communication. Set them by front key operations of the GCS-300. . • The settable range is the same as key operation. Refer to the Command table for the communication command. • All commands are composed of ASCII codes. • The data (setting value) is converted to hexadecimal number, and ASCII code is used. Negative number is represented by 2's complement. · When the data (setting value) has a decimal point, make the value 10 times as much value as the setting. • • All commands are composed of ASCII codes. • The data (setting value) is converted to hexadecimal number, and ASCII code is used. Negative number is represented by 2's complement. • When the setting value has a decimal point, it returns the value by making 10 times as much value as the setting. • Table below describes data item, data and command type. When the setting value for the data has a decimal point, make the value 10 times as much value as the setting and convert to hexadecimal.
● Data items below (00A0H to 00A3H) are to know the specification of the instrument Communication system: Half-duplex Data transfer rate  : 9600bps (2400, 4800, 9600, 19200bps) Selectable by key operation. Synchronous system  : Start-stop Code form Data format         : Start bit  1 Data bit 7 Even parity Parity Stop bit 1 Start bit Data bit
When troubled, make sure the following items after checking the power supply of the host computer and the GCS-300. ● Phenomenon: If it is unable to communicate.
● Phenomenon: Though it is able to communicate, 'NAK' is responded.
If happened unclear phenomenon other than above mentioned, make inquiries about the matters at our agency or the shop where you purchased. Reg. Office : 2-5-1, Senbahigashi, Minoo, Osaka, Japan : http://www.shinko-technos.co.jp URL Tel : 81-72-727-6100 : overseas@shinko-technos.co.jp E-mail Fax: 81-72-727-7006