eyboard and lcd as well as a panel mount printer to provide the operator with additional facilities such as controlling power sockets (timed), monitoring the operators measuring transducers or monitoring operator experiments.
Operators presence sensors can increase airflows and an access key system can prohibit the use of the fc by others.
A sash height sensor can be helpful to monitor and control energy savings. The CMR speech annunciator can warn the operators of danger through preprogrammed voice recordings.

Room pressure control
The room pressure controller has a built-in room pressure transducer which is tubed to air probe plates in the ceiling and referenced to a neutral datum ie plant room. The set point is normally set at -5 Pa. As the sashes are being opened the room becomes more negative and the RP-controller either drives the fan inverter or supply damper to keep -5 Pa steady. The response time is milliseconds and hence excellent control is maintained.
When all sashes are closed a room exhaust damper ie air valve is controlled to keep the room at -5 Pa and to provide heating and cooling for the laboratory. The RP-controller acts as host computer and any FC-controller can be accessed via the keyboard to interrogate a fume cupboard ie sash position, resetting the setpoint of face velocities ie 0ú50 to 0ú95 m/s, muting alarms, etc. The host can also calculate air volumes and schedule the supply proportionally.

Plenum extract pressure control
The plenum pressure controller has a built-in pressure sensor for plenum or duct pressure measurement. In addition, a stack velocity sensor is provided and is connected to the CMR veloprobes fitted in the stacks. Normally a number of fume cupboards are ducted to a roof plenum. The PP-controller is tubed to bulkheads on the plenum and the plenum pressure is controlled to  -165 Pa typically. In order to control the -165 Pa, a fresh air bypass damper is modulated. The stack velocity is normally kept constant by means of inverter control set to a manual speed. The PP-controller monitors the stack velocity and alarms in case of failure. As sashes are being opened and closed, the fresh air bypass dampers moves to fine tolerances to keep -165 Pa steady.
The PP-controller is connected to the communication bus and can be interrogated from any host. The CMR DM5 damper motor response in milliseconds is ideal for accurate plenum control.

PC communication
Any pc can be connected directly to any CMR MPC103 microprocessor controller on the network, the information can be distributed via the server to any point on the user's network.

Room pressure and plenum safety
The CMR PS-pressure switches safeguard the building and are normally set to 6100 Pa for room pressure. In case of excess pressure the switches are hardwired to fans and damper control to provide safe emergency shut-down. The switches can be tailor-made for the client's applications. No building structure damage.