This product provides 20 channels of voltage and thermocouple measurement. It is fitted with specialised non-disconnectable screw terminal thermocouple connectors with integral cold junction compensation which will allow an accuracy of 0.6'C to be achieved on the higher output 

The Alpha 931 module provides 10 isolated digital status inputs which can also be counted, and 10 relay outputs. Each output is isolated and can be used to directly drive switch-gear and other medium AC or DC loads

The Alpha 911 provides 20 channels of voltage and current measurement. Internal current shunts can be connected across the inputs for measuring 4-20mA current loops. The number of channels committed to current measurement using these internal shunts is normally determined when the module is built and shipped. Without current shunts enabled , this module provides voltage measurement at lower cost than the 910 with the convenience of disconnectable screw terminals. External current shunts can be used but accuracy is dependent on integrity of connection and shunt used.

The Alpha 933 module is designed to accurately record digital input changes as they are detected. The module provides 18 fully isolated inputs for timing measurement. The intended application is for monitoring the sequence of events such as trips and control reaction in industrial plant so that alarm or normal operating sequences can be studied. The main function of the 933 is to record changes of inputs against a real time reference. These events are buffered and available to be read into the host computer without risk of missing subsequent events in the process. Each 933 has an independent buffer which can be interrogated as required. The resolution of event recording is 1 mS and synchronisation can be maintained between all 933 recorders