GP485A TDK Corporation, GP485A Datasheet - Page 18

• Manufacturer Part Number: GP485A
• Description: GPIB CONTROLLER
• Manufacturer: TDK Corporation
• Series: ZUPr

Specifications of GP485A

• Accessory Type: Controller
• For Use With/related Products: ZUP Series
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: Q4846340

4.8.2 Address of the serial port
4.8.3 Addressing the GP485 and serial device as listeners
4.8.4 Addressing the GP485 and serial device as talkers
The address of the serial port is the GP485 address plus 1, with the secondary addressing disabled.
However, if primary address of 30 with the configuration switch is selected, the serial port is at 0. The
primary address is set with the DIP switch on the top panel, refer to Par. 4.2.3.
When the GP485 receives it’s own listen address, it examines the data received over the GPIB, treats it
as a programming message, and takes action based on that data. When the GP485 receives the serial
device listen address, it forwards the data over the GPIB to the serial port without examining or
modifying the data. For example: to send a command from user’s computer over the GPIB to the power
supply. Before sending the command to the serial port, the GP485 must be configured to the suitable
serial port parameters.
Follow these steps to send a command from a computer to a Zup power supply
connected to the serial port :
1. Address the GP485 to listen by sending it’s listen address.
2. Send the programming message “sps 9600 n 8 1 “ to the GP485. The GP485 interprets this
3. Address the serial port to listen by sending the serial device listen address to the GP485.
4. Send the command over the GPIB. The GP485 sends the command to the power supply without
The LISTEN LED on the GP485 is lit when either the GP485 or the serial device is addressed to listen.
When the GP485 receives it’s own talk address, it sends out status information. When the GP485
receives the serial device talk address, it sends data out to the GPIB that it has received from the serial
device. For example: User requests power supply to return status information.
Follow the following steps to retrieve the data:
1. Address the serial power supply to talk by sending the serial device talk address to the GP485. If the
2. Perform a GPIB read of 100 bytes. The GP485 retrieves 100 bytes from it’s serial port receive buffer
3. Find out if the serial power supply has sent more bytes to the GP485 by asking the GP485 to send
The status information returned contains the number of bytes remaining in the serial port receive buffer.
This information helps the user to decide how much data to continue to collect from the serial device.
The TALK LED on the GP485 is lit when either the GP485 or the serial power supply is addressed to
talk.
GP485 receives the serial device talk address, but has no data in it’s serial port receive buffer to send
programming message and acts upon it without sending any data on to the serial device.
examining it for meaning.
it waits for data from the serial power supply to fill the request.
and sends them to the user.
status information.
a. Send the GP485 it’s listen address.
b. Send the programming message
c. Send the GP485 it’s talk address.
d. Perform a GPIB read of 20 bytes. The GP485 sends it’s status information, terminated by the GPIB
END message. If the GP485 receives it’s talk address but has nothing to send, it responds to GPIB
reads with a carriage return and a linefeed, accompanied by END.
st
at n to the GP485.