synApps: quadEM

Module Owner: Mark Rivers: University of Chicago

This page is the home of quadEM.

quadEM supports the Quad Electrometer built by Steve Ross from the APS. This device consists of a 4-channel digital electrometer unit and 2 VME boards. It is typically used for photodiode-based x-ray beam position monitors, although it can be used for any low-current measurement that requires high speed digital input. The device provides 2 readings per diode at up to 813 Hz.

The quadEM software includes an asyn driver that provides support for the following:

• Analog input records using the standard asyn device support. This provides digitally averaged readings of the current, sum, difference and position at speeds up to 10 Hz with standard EPICS scan times.
• mca record. This provide a time-history (like a digital scope) of the current, sum, difference and position at speeds up to 813 Hz. The time per point can be greater, in which case it does averaging.
• epid (fast feedback). This provides fast feedback via an asyn D/A converter (e.g. dac128V) at speeds up to 813Hz. If it is run slower it does signal averaging.

Please email any comments and bug reports to Mark Rivers who is responsible for coordinating development and releases.

Where to find it

You can download the software from the links in the table below:

Required Modules

The quadEM support typically uses the synApps modules mca (for digital scope mode), std (for the EPID fast feedback support), and ipUnidig for interrupt support .  But the quadEM module does not actually depend on these other modules to be built.

Installation and Building

After obtaining a copy of the distribution, it must be installed and built for use at your site. These steps only need to be performed once for the site (unless versions of the module running under different releases of EPICS and/or the other required modules are needed).

1. Create an installation directory for the module, usually this will end with
   
   .../support/
   
2. Place the distribution file in this directory. Then issue the commands (Unix style)

   gunzip quadEMRX-Y.tar.gz
   
   tar xvf quadEMRX-Y.tar
   

   where X-Y is the release.
3. This creates a <top> application.
   

   .../support/quadEMRX-Y
   

4. Edit the config[ure]/RELEASE file and set the paths to your installation of EPICS base and to your versions of other required modules.
5. Run gnumake in the top level directory and check for any compilation errors.
6. Please email Mark Rivers so that a record can be kept of which sites are using this software.

In Use

This software was originally developed by Mark Rivers.

• ANL/APS : In use at CARS and IMCA. To be used soon at XOR and a number of other beamlines.