Enhancements over medm:
- medm_cdev uses cdev instead of channel access as network communication layer. By doing so, it enables medm_cdev to display and monitor data not only from channel access servers but also from other network servers that have cdev interface.
- medm_cdev used a free Motif 2d plotting widget in place of XRT commercial widget. Currently one can compile and run on most Unix platforms with Motif.
- A bug which is related to the limit on the open file descriptors has been fixed.
- medm_cdev supports more flexible data monitoring/controlling scheme. In the existing medm, one can only specify channel name to monitor. Now in addition to the above, one can specify "device verb attribute" to a display. For example: "cdev_ai0 get VAL" or "cdev_ai0 monitorOn VAL".
How to install:
medm_cdev can be installed in two ways.
- You can unpack medm_cdev entirely in the epics distribution under $EPICS/extensions/src. The take a look at a medm_cdev/medm/Makefile.Unix and make sure all flags are correct. Then typing gmake will do it. The medm_cdev will be installed in $EPICS/extesions/$(ARCH)/bin.
- You can unpack medm_cdev anywhere. In the top directory there
is a _makef which is a Makefile for people without the whole EPICS
distribution. Take look at a _makef and choose a correct operating
system, and type make -f _makef. The medm_cdev will be installed
in the same directory. The _makef is a quick hack for now.
Note: You may have to get EPICS license to run medm_cdev.
- Currently medm_cdev has been compiled and tested on hpux09, hpux10, solaris-2.x and Linux-2.0.x
How to use medm_cdev:
Complete documentation on medm can be found at APS
The medm_cdev works with existing adl files created by existing medm. In addition, the medm_cdev also allows one to use "device verb attribute" to specify how to display an attribute.
Requirements for cdev services:
- In order to use medm_cdev with a cdev service, the service has to support message "get attribute" at least.
- If one wants to use medm_cdev to monitor a set of strings as choices,
the service has to return a cdevData with "displayHigh", "displayLow",
and "value" tags in it. For Example:
char** selections; int numselections = 10; cdevData result; result.insert ("value", selections); result.insert ("displayHigh", numselections - 1); result.insert ("displayLow", 0);If returned dada has no "displayHigh" and "displayLow", the medm_cdev will not display 'selections' properly.