Edwards STP-iXA4507 Series User Manual

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STP-iXA4507 series Turbomolecular Pump

MT-91E-001-0

Page 78

SERIAL COMMUNICATION PROTOCOL

PAG

5.3.12 Application note

Noise generated by many factors such as the type or length of cable, communication speed, and

different communication devices may cause communication failure with a serial port. It is very difficult

to prevent a communication failure completely. The followings are the methods to create tool

applications with redundancy to noise.

• Be sure to communicate according to the protocol. If it communicates by different procedures

described by this manual, communication failure might cause.

Figure 40 shows the block diagram of the valid communication process from sending a command

to receiving answer data.

Moreover, examples of the communication procedures are shown in Figure 44, Figure 45, and

Figure 46.

SIM

ACK

Reply (A)

Answer

Reply (A)

Command

Send (A)

ACK

Send (A)

Command

Send (B)

ACK

Reply (B)

Answer

Reply (B)

ACK

Send (B)

Figure 40 - Block diagram of communication process example

• A SIM will reply "ACK" or "NAK" within approximately 2 seconds after receiving a command.

If there is no reply, the SIM may not have received the command. In this case, resend the

command from an equipment application before regarding it as a communication failure. If the

problem cannot solve after resending it several times, make a process of communication failure

on the equipment application.

• Monitor the character "Etx" in the process of finishing receiving data.

The receiving process is completed by receiving the "LRC" (checksum) data after getting "Etx".

This process can reduce the task of modifying an equipment application if receiving commands

with different answer data sizes according to the pump mode.

However, when judging the completion of the answer receiving process by the number of

received characters, check that "Etx" has been received, and the LRC checksum is correct.

• After sending the command, release the elapsed time process due to communication timeout

when receiving answer data. When receiving many answer data, the answer receiving process of

an equipment application may regard time out, and all data may not be able to obtain.

Questions and Answers:

W
wpayneAug 8, 2025
What to do if the 'STATUS' LED flashes red on my Edwards STP-iXA4507 Water Pump?
- S
  sarahlangAug 8, 2025
  If the 'STATUS' LED flashes red, you should first follow the recommended actions given in Table 37 to address the probable cause of the abnormality. Next, perform the RESET operation to change the 'STATUS' LED to flash green. Finally, perform the START operation to check if the Edwards Water Pump operates correctly.
J
jamessusanAug 22, 2025
What to do if 'STATUS' LED doesn't turn green after RESET on Edwards Water Pump?
- C
  Christopher BuckleyAug 22, 2025
  If the 'STATUS' LED does not change to a green flash even after performing a RESET, confirm that the Edwards Water Pump has stopped. Turn OFF the primary power (switch 'OFF'), and then turn it back ON (switch 'ON').