TDK 750W, 1500W technical manual Communication Interface Protocol

7.5.2Multi power supply connection to RS232 or RS485 bus

Up to 31 units can be connected (daisy chained) to the RS232 or RS485 bus. The first unit connects to the controller via RS232 or RS485 and the other units are connected via the RS485 bus.

1.First unit connection: Refer to Section 7.5.1 for connecting the first unit to the controller.

2.Other units connection: The other units on the bus are connected via their RS485 interface. Refer to Figure 7-5 for typical connection.

-Set rear panel setup switch SW1-6 to its UP position.

-Using the Linking cable supplied with each unit (refer to Fig. 7-6), connect each unit OUT

connector to the next unit IN connector.

RS232/RS485 RS485 RS485 RS485

IN	OUT	IN	OUT	IN	OUT	IN	OUT
POWER SUPPLY		POWER SUPPLY		POWER SUPPLY		POWER SUPPLY
	#1		#2		#3		#31

Fig7-5: Multiple power supply RS232/485 connection

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L=0.5m typ.

	PIN NO.	NAME	PIN NO.	NAME
	HOUSING	SHIELD	HOUSING	SHIELD
1		SG	1	SG
6		TXD -	6	RXD -
3		TXD +	3	RXD +
	5	RXD -	5	TXD -
	4	RXD +	4	TXD +

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1

Fig.7-6: Serial link cable with RJ-45 shielded connectors (P/N: GEN/RJ-45)

7.6 COMMUNICATION INTERFACE PROTOCOL

NOTE

The address (ADR n) command must return an “OK” response before any other commands are accepted.

7.6.1 Data format

Serial data format is 8 bit, one start bit and one stop bit. No parity bit.

7.6.2Addressing

The Address is sent separately from the command. It is recommended to add 100msec delay be- tween query or sent command to next unit addressing. Refer to Section 7.8.3 for details.

7.6.3End of Message

The end of message is the Carriage Return character (ASCII 13). The power supply ignores the Line Feed (ASCII 10) character.

7.6.4Command Repeat

The backslash character “\” will cause the last command to be repeated.

7.6.5Checksum

The user may add a checksum (optional) to the end of the command. The checksum is “$” followed by two hex characters. If a command or a query has a checksum, the response will also have one. There is no CR between the command string and the “$” sign.

Example: STT?3A STAT?$7B

7.6.6Acknowledge

The power supply acknowledges received commands by returning an “OK” message. If an error is detected the power supply will return an error message. The rules of checksum also apply to the ac- knowledge.

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