Experimental Physics and
Industrial Control System

"Walters, M \(Malcolm\)" <[email protected]> · Fri, 16 Dec 2005 08:35:09 -0000

At Diamond we have also successfully communicated with this device over
RS232 using the same settings as Lewis. The unit number is set by 4 dip
switches inside the box. Be careful opening the box since the "power on"
led has quite a short cable.

As suggested by Lewis, I would start by checking you are sending data to
the correct pin. The cable must be a null-modem type with the crossover
between pins 2 and 3 rather than a straight through cable.

One thing we found very useful for solving problems was a serial
analyser. The one we use is from
http://www.new-forest-electronics.co.uk/index.htm although many others
exist. This can check exactly what you are sending and what replies are
sent back.

Note that if you have flow control turned off there is no need to
connect pins 4,6 and 8 on the ioc. These are just there to short the
terminal ready signal (DTR - Pin 4) back into data set ready (DSR - Pin
6) and clear to send (CTS - Pin 8).

Malcolm

-- 
Malcolm Walters
01235 778557
Diamond Light Source Ltd. 
Rutherford Appleton Laboratory,
Chilton, Didcot, Oxfordshire OX11 0QX
[email protected]

-----Original Message-----
From: J. Lewis Muir [mailto:[email protected]] 
Sent: 15 December 2005 16:01
To: [email protected]
Subject: Re: Oxford Danfysik-YMCS0012

On Thu, Dec 15, 2005 at 09:08:19AM -0600, Chithra Karunakaran wrote:
> Hi:
>  
> Has anyone worked with Oxford Danfysik Beam Position monitoring system
> (4 channel IC plus Electronics Unit, YMCS0012).  The device does not 
> respond to any of the commands send through the serial port.
>  
> Thanks,
> Chithra.

Hi. I have.

I am able to communicate with it with the following RS-232 settings:

Baud rate: 19200
Data format: 8 bits
Stop bits: 1
Parity: none
Flow control: none 

Also, if you have only one device (i.e. you are not chaining the
devices), your RS-232 cable must be wired correctly. The wiring should
be as follows:

VME  <->  QBPM
---       ----
2         3
3         2
5         5
4-6-8

On the end that connects to the VME IOC, pins 4, 6, and 8 should be tied
together.

If you have more than one device, the wiring needs to be different (see
section 6.6 on page 13 of the manual).

A command you can send is ":READ1:CURRALL?" terminated with "\n" (ASCII
10 / linefeed) to read all four current channels at once. Replace the 1
after "READ" with the unit address assigned to your device. Or if you
don't know it, try 0-15 if 1 doesn't work.

Hope this helps.

-lewis

--
J. Lewis Muir
Software Engineer
CARS/IMCA-CAT

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System