MDIF Epics Module
-----------------

An Asyn and Stream Device based driver for the Multi-Detector Interface used at
some instrument within SINQ.

## How to Use

Unless a custom database is needed, a device can be configure simply by setting
the required environment variables when calling the MDIF start script.

Required Variables

| Environment Variable | Purpose                                 |
|----------------------|-----------------------------------------|
| INSTR                | Prefix of all device specific PVs       |
| NAME                 | First field in all PVs after Prefix     |
| MDIF\_IP             | Network IP of device                    |
| MDIF\_PORT           | Network Port of device                  |

All PVs take the form

```
$(INSTR)$(NAME):*
```

Available device startup scripts

* scripts/mdif.cmd

For example

```
epicsEnvSet("INSTR", "SQ:INSTRUMENT:") # can also be set in runScript call

runScript "$(mdif_DIR)mdif.cmd" "NAME=MDIF, MDIF_IP=focus-ts, MDIF_PORT=3016"
```

## PVs of Interest

| PV                           | Description                                      |
|------------------------------|--------------------------------------------------|
| \$(INSTR)\$(NAME):MsgTxt     | Contains unexpected response to executed command |
| \$(INSTR)\$(NAME):DELAY      | Used to write a new delay value to the MDIF      |
| \$(INSTR)\$(NAME):DELAY\_RBV | Read back the delay value configured in the MDIF |

## Simulation

Simulation of the Hardware can be toggled on as follows:

```
epicsEnvSet("SET_SIM_MODE","") # run MDIF simulation instead of connecting to actual system
runScript "$(mdif_DIR)mdif.cmd" "NAME=MDIF, MDIF_IP=localhost, MDIF_PORT=3016"
```

In such a case, the provided `MDIF_IP` is ignored, and a python program
simulating the hardware is started in the background, listening at the
specified `MDIF_PORT`.

See [sim/mdif\_sim.py](sim/mdif_sim.py).