Legacy products are typically PLCs that have been superseded by upgraded versions, along with related accessory products. For most customers, the upgrades are backwards compatible with programs written for the legacy versions. In some instances however, a customer may be using certain features in an legacy PLC that requires some modification in the PLC program when the new model is adopted instead.

As far as possible, Triangle Research Int'l tries to maintain a certain inventory of legacy products for emergency replacement purposes only. While Triangle Research Int'l cannot gurantee ongoing stock availability of legacy products, we can give assurance that we will always provide ongoing technical consultancy and repair support for all products that we manufacture.