RS232 with a DMM (EXTECH MM570)


Thread Starter

Scott K.

I have to write an application in VB that communicates with an EXTECH MM570 DMM. I have never used the serial port with VB. They sent the protocol, but I'm not sure how to use it. This is what they told me "After sending out seven commands 10h, 02h, 00h, 00h, 00h, 10h, & 03h to meter, meter will send out 22 bytes data as shown in file." They also sent this: Program initiated procedures for COM port
1. Initiate COM port
2. Wait for 100ms
3. Set RTS=1
4. Wait for 100ms
3. Set RTS=0
4. Wait for 100ms
5. Set RTS=1
I have tried various methods using the MSComm control with no luck in receiving any data back from the meter. Has anyone ever done anything with this meter or something similar. I would greatly appreciate any help.
Scott K.

Cury Wuollet

Sounds like you need low level control of the handshake lines. Wiggling RTS probably enables the port and starts the recieve routine. I'm not sure you have this degree of control fron VB but, then I don't do Microsoft.

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