Rane NM 84, Operator'S Manual

Page: 14 / 19

Manual-14
NM 84 ActiveX Example
The short version of the FrontPage 2000 procedure used to
setup a web page with ActiveX controls for a Rane NM 84
device’s parameters goes as follows:
Insert a Rane NM 84 ActiveX control in a new web page.
(This software/control ships with the unit or can be found on
our website. Running this NM 84 setup procedure registers
the Rane NM 84 ActiveX control with the computer used to
create the web page. Otherwise, no special icon or folder is
created after running the setup, so save time by not looking
for the NM 84 software/control other than from within
FrontPage’s ActiveX list.) Set the inserted NM 84 control’s
Properties for your application. Generally, from FrontPage’s
ActiveX Control Properties window, this involves providing a
unique Name in the Object Tag tab for the control. Then, link
this control to the specific NM 84 device by entering the NM
84 device’s IP address in the NM 84 SNMP Control Setting
tab. The NM 84 control also must be assigned an update rate
which is found on the NM 84 SNMP Control Setting tab. A
good default value might be “5” which provide an update
every half second. Don’t get overzealous with this update rate
since it’s a function of many things and can negatively effect
the speed at which controls and parameter changes take effect.
Next, insert an ActiveX slider, button or what have you
from the vast list of available ActiveX controls. If you can’t
find a control that suits your fancy, further ActiveX controls
can be found on the Internet as shareware, bought from
ActiveX providers often in packages or created from scratch
for complete customization. Adjust the size, orientation and
placement of the control for optimum ergonomics being sure
to consider the user, the application and the requirement for
further controls on this same page. Keeping the number of
total controls on any one page low is very wise. See why in
the September, 2000 AES preprint by Rane’s Stephen
Macatee and Devin Cook titled Controlling Audio Systems
With ActiveX Controls Over CobraNet And Other Ethernet-
Based Networks.
In the ActiveX Control Properties window for the slider
(or button ), uniquely Name the control in the Object Tag
tab. Then in the Parameters tab, set the control’s maximum
and minimum value to match the NM 84 device’s parameter
that you’ll link to this slider. Sometimes you’ll find that you’ll
need to adjust these maximum and minimum values here (or
in the Script language discussed next) to properly display or
be compatible with the parameter being adjusted. For ex-
ample, the “Mic_Trim” ActiveX control has a minimum value
of “0” and a maximum of “36,” but the actual displayed range
of the Trim control is -20 to +16 dB in 1 dB steps. Thus, there
are “36,” 1 dB steps. Also, often the control link may be
backwards such that the maximum value may correspond to
the “lowest” slider position. Fix this when updating the
control by subtracting the control’s maximum setting from the
desired setting within FrontPage’s VBScript language.
To link the slider to the desired NM 84 internal device
parameter, use Microsoft’s VB Script language by associating
the slider’s Name with the specific NM 84 Control Name.
You’ll find the list of valid NM 84 ActiveX Control Names at
the end of this Manual.
To track slider or system changes and update either the
web page, the NM 84 device, or both, we’ll need to use
Microsoft’s Visual Basic Script language. This is where the
programming comes in. Yes, it does say programming.
Remember when you could do your job without the need to
program anything except the time on your wind up watch?
Some programming tasks here are things like initializing the
controls with valid information usually by reading the NM 84
device’s current settings, then updating the on-screen controls
so they match the device. You also need the Script software to
scan for any changes and make updates accordingly. It is also
wise to be sure that any requested changes to parameter values
are within the proper numerical range, thus avoiding strange
and unpredictable behavior. This is usually called “bounds
checking” by programmers. Since these web page and
network technologies allow multiple control locations, be sure
your code handles this. For example, NM 84 device param-
eters can be changed from the NM 84’s front panel, from the
web page itself, from another copy of the same web page
being run elsewhere on the network, or changes can also be
made from contact closure memories. Take this into account
when writing the “update settings” code by scanning indepen-
dently for changes to the device’s settings and changes to the
web page controls. Then update things so the device settings
and the web page controls always match. The Rane has
example code with comments.